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1 15 unneback 
//--------------------------------------------------------------------------
2 
// This is the property of PERFTRENDS TECHNOLOGIES PRIVATE LIMITED and
3 
// possession or use of file has to be with the written LICENCE AGGREMENT
4 
// from PERFTRENDS TECHNOLOGIES PRIVATE LIMITED.
5 
//
6 
//--------------------------------------------------------------------------
7 
//
8 
// Project : ATMEL Data Flash Device
9 
//--------------------------------------------------------------------------
10 
// File         : $RCSfile: AT26DFxxx.v,v $
11 
// Path         : $Source: /home/cvs/atmel_flash_dev/design_26x/AT26DFxxx.v,v $
12 
// Author       : $ Devi Vasumathy N $
13 
// Created on   : $ 13-03-07 $
14 
// Revision     : $Revision: 1.8 $
15 
// Last modified by : $Author: devivasumathy $
16 
// Last modified on : $Date: 2007/05/10 05:15:51 $
17 
//--------------------------------------------------------------------------
18 
// Module               : AT26DFxxx.v
19 
// Description          : BFM for devices AT25DF041A, AT26DF081A,
20 
//                        AT26DF161A, AT26DF321
21 
//
22 
//--------------------------------------------------------------------------
23 
//
24 
// Design hierarchy : _top.v/top_1.v/top_2.v/...
25 
// Instantiated Modules : top_1.v, top_2.v
26 
//--------------------------------------------------------------------------
27 
// Revision history :
28 
// $Log: AT26DFxxx.v,v $
29 
// Revision 1.8  2007/05/10 05:15:51  devivasumathy
30 
// Card Memory preload
31 
//
32 
// Revision 1.7  2007/04/27 09:09:40  devivasumathy
33 
// *** empty log message ***
34 
//
35 
// Revision 1.6  2007/04/17 10:50:59  devivasumathy
36 
// Timing verified
37 
//
38 
// Revision 1.5  2007/04/16 06:24:44  devivasumathy
39 
// *** empty log message ***
40 
//
41 
// Revision 1.4  2007/04/10 09:37:36  devivasumathy
42 
// *** empty log message ***
43 
//
44 
// Revision 1.3  2007/04/09 12:06:09  devivasumathy
45 
// *** empty log message ***
46 
//
47 
// Revision 1.2  2007/04/05 14:45:12  devivasumathy
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// *** empty log message ***
49 
//
50 
// Revision 1.1  2007/04/05 11:32:18  devivasumathy
51 
// AT26DFx data flash model
52 
//
53 
//--------------------------------------------------------------------------
54 
 
55 
`timescale 1ns/10ps      //ME added
56 
 
57 
`define def_321 1        //ME added
58 
 
59 
 
60 
module AT26DFxxx (
61 
                CSB,
62 
                SCK,
63 
                SI,
64 
                WPB,
65 
`ifdef def_321
66 
`else
67 
                HOLDB,
68 
`endif
69 
                SO);
70 
 
71 
// ******************************************************************** //
72 
//                      Port Declaration:
73 
// ******************************************************************** //
74 
 
75 
input   CSB;            // Chip Select!
76 
input   SCK;            // Serial Clock
77 
input   SI;             // Serial Input
78 
input   WPB;            // Write Protect!
79 
`ifdef def_321
80 
`else
81 
input   HOLDB;          // Hold!
82 
`endif
83 
output  SO;             // Serial Output
84 
 
85 
`ifdef def_321
86 
        wire  HOLDB;
87 
`endif
88 
 
89 
parameter DEVICE = "AT25DF041A";        // Device selected
90 
parameter PRELOAD = 1;                  // preload memory with content in MEMORY_FILE
91 22 julius 
parameter MEMORY_FILE = "flash.in";     // Memory pre-load
92 15 unneback 
 
93 
// ********************************************************************* //
94 
//Timing Parameters :
95 
// ******************************************************************** //
96 
 
97 
// Fixed parameters
98 
parameter fRDLF   = 33;         // SCK Frequency for read Array (Low freq - 03h opcode)
99 
//representation in ns
100 
parameter tDIS    = 6;          // Output Disable time
101 
parameter tV      = 6;          // Output Valid time
102 
parameter tOH     = 0 ;          // Output Hold time
103 
 
104 
parameter tHLQZ   = 6 ;         // HOLD! Low to Output High-z
105 
parameter tHHQX   = 6 ;         // HOLD! High to Output Low-z
106 
 
107 
parameter tSECP   = 20;         // Sector Protect Time
108 
parameter tSECUP  = 20;         // Sector Unprotect Time
109 
 
110 
parameter tEDPD   = 3000;       // Chip Select high to Deep Power-down (3 us)
111 
parameter tRDPD   = 3000;       // Chip Select high to Stand-by Mode
112 
parameter tWRSR   = 200;        // Write Status Register Time
113 
parameter tPP     = 5000000;    // Page Program Time
114 
parameter tBLKE4  = 200000000;  // Block Erase Time 4-kB
115 
parameter tBLKE32 = 600000000;  // Block Erase Time 32-kB
116 
parameter tCHPEn  = 1000000000; // local chip erase time
117 
 
118 
// variable parameters
119 
// ******************************************************************** //
120 
//parameter tBP     = 7000;             // Byte Program Time
121 
//parameter tBLKE64 = 950000000;        // Block Erase Time 64-kB
122 
//parameter tCHPE   = 3000000000;       // Chip Erase Time // this is actual;
123 
                                        // due to simulation warning splitted into 2 parameters as tCHPE = tmult * tCHPEn
124 
//parameter tmult   = 3;                // Multiplication factor for chip erase timing
125 
 
126 
parameter tBP =         (DEVICE == "AT25DF041A") ? 7000 :
127 
                        (DEVICE == "AT26DF081A") ? 7000 :
128 
                        (DEVICE == "AT26DF161A") ? 7000 :
129 
                        (DEVICE == "AT26DF321")  ? 6000 : 7000;
130 
 
131 
parameter tBLKE64 =     (DEVICE == "AT25DF041A") ? 950000000 :
132 
                        (DEVICE == "AT26DF081A") ? 950000000 :
133 
                        (DEVICE == "AT26DF161A") ? 950000000 :
134 
                        (DEVICE == "AT26DF321")  ? 1000000000 :950000000 ;
135 
 
136 
parameter tmult =       (DEVICE == "AT25DF041A") ? 3 :
137 
                        (DEVICE == "AT26DF081A") ? 6 :
138 
                        (DEVICE == "AT26DF161A") ? 12 :
139 
                        (DEVICE == "AT26DF321")  ? 36 : 3;
140 
 
141 
//parameter fSCK    = 70;       // Serial clock (SCK) Frequency in MHz
142 
//parameter tSCKH   = 6.4;      // SCK High time
143 
//parameter tSCKL   = 6.4;      // SCK Low time
144 
 
145 
parameter fSCK =        (DEVICE == "AT25DF041A") ? 70 :
146 
                        (DEVICE == "AT26DF081A") ? 70 :
147 
                        (DEVICE == "AT26DF161A") ? 70 :
148 
                        (DEVICE == "AT26DF321")  ? 66 : 70;
149 
 
150 
parameter tSCKH =       (DEVICE == "AT25DF041A") ? 6.4 :
151 
                        (DEVICE == "AT26DF081A") ? 6.4 :
152 
                        (DEVICE == "AT26DF161A") ? 6.4 :
153 
                        (DEVICE == "AT26DF321")  ? 6.8 : 6.4;
154 
 
155 
parameter tSCKL =       (DEVICE == "AT25DF041A") ? 6.4 :
156 
                        (DEVICE == "AT26DF081A") ? 6.4 :
157 
                        (DEVICE == "AT26DF161A") ? 6.4 :
158 
                        (DEVICE == "AT26DF321")  ? 6.8 : 6.4;
159 
// ******************************************************************** //
160 
 
161 
// ********************** Manufacturer ID ********************** //
162 
parameter [31:0] MAN_ID = (DEVICE == "AT25DF041A") ? 32'h1F_04_00_00 :
163 
                        (DEVICE == "AT26DF081A") ? 32'h1F_45_01_00 :
164 
                        (DEVICE == "AT26DF161A") ? 32'h1F_46_01_00 :
165 
                        (DEVICE == "AT26DF321")  ? 32'h1F_47_00_00 : 32'h1F_04_00_00;
166 
 
167 
// ********* Memory And Access Related Declarations ***************** //
168 
 
169 
parameter BLOCK64 =     (DEVICE == "AT25DF041A") ? 8  : // no of 64kB blocks
170 
                        (DEVICE == "AT26DF081A") ? 16 :
171 
                        (DEVICE == "AT26DF161A") ? 32 :
172 
                        (DEVICE == "AT26DF321")  ? 64 : 8 ;
173 
 
174 
parameter SECTOR =      (DEVICE == "AT25DF041A") ? 11 : // no of sectors
175 
                        (DEVICE == "AT26DF081A") ? 19 :
176 
                        (DEVICE == "AT26DF161A") ? 32 :
177 
                        (DEVICE == "AT26DF321")  ? 64 : 11 ;
178 
 
179 
// total memory size = no. of blocks * 64 k bits (i.e each block contains 64 KB)
180 
parameter MEMSIZE = BLOCK64 * 64 * 1024; // total memory size
181 
 
182 
reg [7:0] memory [MEMSIZE-1:0]; // memory of selected device
183 
reg [7:0] status_reg;            // Status register
184 
reg [63:0] sector_reg;           // Sector protection reg
185 
reg [7:0] int_buffer [255:0];     // internal buffer to store data in page programming mode
186 
// ****************** ***************** ***************** //
187 
 
188 
 
189 
// ********* Registers to track the current operation of the device ******** //
190 
reg deep_power_down;            // Device in Deep Power Down Mode
191 
reg status_read;                // Status register is being read
192 
reg erasing_block4;             // 4kB block erase
193 
reg erasing_block32;            // 32kB block erase
194 
reg erasing_block64;            // 64kB block erase
195 
reg erasing_chip;               // chip erase
196 
reg rd_dummy;                   // low/high freq read array
197 
reg byte_prog;                  // Byte/page programming
198 
reg seq_byte_prog;              // sequential byte programming
199 
reg seq_byte_start;             // sequential byte programming start intimation
200 
 
201 
 
202 
// ********* Events to trigger some task based on opcode *********** //
203 
event  EDPD;            // Deep Power-down (enable)
204 
event  RDPD;            // Resume from Deep Power-down
205 
event  RA;              // Read Array
206 
//event  RAL;           // Read Array (Low frequency)
207 
event  BE4;             // Block Erase 4KB
208 
event  BE32;            // Block Erase 32KB
209 
event  BE64;            // Block Erase 64KB
210 
event  CE;              // Chip Erase
211 
event  BP;              // byte /page program
212 
//event  SBPE;          // Sequential Byte Program Mode Erase
213 
event  SBP;             // Sequential Byte Program
214 
event  WE;              // Write Enable
215 
event  WD;              // Write Disable
216 
event  PS;              // Protect Sector
217 
event  UPS;             // Un-Protect Sector
218 
event  RSPR;            // Read Sector Protection Register
219 
event  RSR;             // Read Status Register
220 
event  WSR;             // Write Status Register
221 
event  MIR;             // Manufacturer ID Read
222 
 
223 
 
224 
/******** Other variables/registers ******************/
225 
reg [23:0] temp_addr;            // to store mem address temporarily
226 
reg [23:0] current_address;      // to store mem address
227 
reg [7:0] temp_data;             // temp read data from memory
228 
reg [7:0] data_in;               // data in for byte programming
229 
reg [7:0] read_data;             // register in which opcode/data is read-in
230 
reg [7:0] read_dummy;            // register in which dont care data is stored
231 
reg [3:0] stat_reg_temp; // WSR temp value for global protec/unprotect
232 
reg [7:0] pp_address;            // specifies the page address for BP/PP
233 
reg SO_reg;                     // Signal out reg
234 
reg SO_on;                      // Signal out enable signal
235 
reg SPRL;                       // Sector Protection Register Locked
236 
reg SPM;                        // Sequential Program Mode Status
237 
reg EPE;                        // Erase/Program Error
238 
reg WPP;                        // Write Protection Pin Status
239 
reg [1:0] SWP;                   // Software Protection Status
240 
reg WEL;                        // Write Enable Latch Status
241 
reg RDYnBSY;                    // Ready/Busy Status
242 
reg lock;                       // to lock SPRL bit of status reg
243 
reg unlock;                     // to unlock SPRL bit of status reg
244 
reg global_protect;             // global protection
245 
reg global_unprotect;           // global unprotect
246 
reg protect;                    // to protect Sector reg bits
247 
reg unprotect;                  // to unprotect Sector reg bits
248 
reg protected;                  // check protection status of sector reg
249 
reg SPRL_val;                   // WSR temp value for SPRL
250 
integer i,j,k,l;                // integers for accessing memory
251 
integer pp;                     // specifies no of bytes need to write in memory
252 
integer pp_j;                   // holds no of bytes received for page program
253 
integer pp_i;                   // holds no of bits received for each byte in page program
254 
integer dummy;                  // counter for receiving 8 dummy bit from SO
255 
integer delay;                  // waits for Chip Erase to complete
256 
 
257 
real tperiod;                   // time period - on period
258 
real tperiod1;                  // time period - off period
259 
reg freq_error;                 // frequency limit exceeds indication
260 
 
261 
 
262 
// ****************** Initial Block **************** //
263 
`ifdef def_321
264 
        assign HOLDB = 1'b1;
265 
`endif
266 
 
267 
initial
268 
begin
269 
 
270 
// Memory Initialization
271 
//To pre-load Memory (in Hex format), use parameter MEMORY_FILE = <filename>,
272 
//where <filename> is the name of the pre-load file.
273 
//If PRELOAD = 0, the Memory is initialized to Erased state (all data = FF).
274 
//If PRELOAD = 1, the Memory is initialized to PreLoad state (data in pre-load file).
275 
 
276 
        for(i=0; i<BLOCK64; i=i+1)                       // Block64K access
277 
        begin
278 
            for(j=0; j<2; j=j+1)                 // Block32K access
279 
            begin
280 
                for(k=0; k<8; k=k+1)                     // Block4K access
281 
                begin
282 
                    for(l=0; l < 12'hfff; l=l+1)
283 
                    begin
284 
                        memory[l] = 8'b11111111;
285 
                    end
286 
                end
287 
            end
288 
        end
289 
 
290 
// Memory Initialization for preloading condition
291 
if(PRELOAD==1)
292 
begin
293 
        $readmemh (MEMORY_FILE, memory);
294 
end
295 
 
296 
 
297 
// Status register initialization
298 
SPRL = 1'b0;
299 
SPM = 1'b0;
300 
EPE = 1'b0;
301 
WPP = 1'b0;
302 
SWP = 2'b11;
303 
WEL = 1'b0;
304 
RDYnBSY = 1'b0; // device is ready
305 
status_reg[7]   = SPRL;
306 
status_reg[6]   = SPM;
307 
status_reg[5]   = EPE; // reserved
308 
status_reg[4]   = WPP;
309 
status_reg[3:2] = SWP;
310 
status_reg[1]   = WEL;
311 
status_reg[0]    = RDYnBSY;
312 
//status_reg = {1'b1,1'b0,1'b0,1'b0,2'b11,2'b0};
313 
 
314 
sector_reg = 64'hFFFFFFFFFFFFFFFF;
315 
 
316 
// Stand-by mode initialization
317 
current_address  = 24'b0;
318 
data_in          = 8'b0;
319 
stat_reg_temp    = 4'b0;
320 
deep_power_down  = 1'b0;
321 
status_read      = 1'b0;
322 
rd_dummy         = 1'b0;
323 
seq_byte_start   = 1'b0;
324 
SO_on            = 1'b0;
325 
global_protect   = 1'b0;
326 
global_unprotect = 1'b0;
327 
SPRL_val         = 1'b0;
328 
lock             = 1'b0;
329 
unlock           = 1'b0;
330 
dummy            = 0;
331 
 
332 
deep_power_down = 1'b0;
333 
status_read     = 1'b0;
334 
erasing_block4  = 1'b0;
335 
erasing_block32 = 1'b0;
336 
erasing_block64 = 1'b0;
337 
erasing_chip    = 1'b0;
338 
rd_dummy        = 1'b0;
339 
byte_prog       = 1'b0;
340 
seq_byte_prog   = 1'b0;
341 
seq_byte_start  = 1'b0;
342 
 
343 
end // end of initial
344 
 
345 
// ********************** Drive SO ********************* //
346 
bufif1 (SO, SO_reg, SO_on); //SO will be driven only if SO_on is High
347 
 
348 
// global protection and unprotection on sectors
349 
always@(global_protect or global_unprotect)
350 
begin
351 
        if(global_protect==1'b1)
352 
                sector_reg = 64'hFFFFFFFFFFFFFFFF;
353 
        else if(global_unprotect==1'b1)
354 
                sector_reg[SECTOR-1:0] = 'b0;
355 
end
356 
 
357 
// ********************* Status register ********************* //
358 
always @(WPB or lock or unlock) //SPRL bit locking & Unlocking
359 
begin
360 
        if(WPB==1'b1 && SPRL==1'b0 && lock==1'b1)
361 
                SPRL = 1'b1;
362 
        else if(WPB==1'b1 && SPRL==1'b1 && unlock==1'b1)
363 
                SPRL = 1'b0; // S/W Locked
364 
        else if(WPB==1'b0 && SPRL==1'b0 && lock==1'b1)
365 
                SPRL = 1'b1;
366 
        else if(WPB==1'b0 && SPRL==1'b1 && unlock==1'b1)
367 
                SPRL = 1'b1; // H/W Locked
368 
end
369 
 
370 
always @(WPB)                   // Write Protect (WP!) Pin Status
371 
begin
372 
        WPP = WPB;
373 
end
374 
 
375 
always @(sector_reg)            // Software Protection Status
376 
begin
377 
        if(sector_reg[SECTOR-1:0]=='d0)
378 
                SWP = 2'b00;
379 
        else if((|sector_reg==1'b1) && (&sector_reg==1'b0))
380 
                SWP = 2'b01;
381 
        else if(&sector_reg==1'b1)
382 
                SWP = 2'b11;
383 
end
384 
 
385 
always @(SPRL or SPM or EPE or WPP or SWP or WEL or RDYnBSY)
386 
begin
387 
        status_reg = {SPRL,SPM,EPE,WPP,SWP,WEL,RDYnBSY};
388 
end
389 
 
390 
// ******* to receive opcode and to switch to respective blocks ******* //
391 
always @(negedge CSB)  // the device will now become active
392 
begin : get_opcode_
393 
 
394 
        //@(negedge SCK);
395 
        get_opcode;  // get opcode here
396 
 
397 
        if (deep_power_down == 1'b1) // Can be only after background has been enabled
398 
                case (read_data)
399 
                        8'hAB:  // Resume from Deep Power-down
400 
                        begin
401 
                                $display("Opcode(%h) for Resume from Deep Power-down received",read_data);
402 
                                -> RDPD;
403 
                        end
404 
                        default :
405 
                        begin
406 
                                $display ("Opcode %h is not allowed: device in Deep Power-down", read_data);
407 
                                disable get_opcode_;
408 
                        end
409 
                endcase
410 
        else
411 
        begin
412 
                case (read_data)        // based on opcode, trigger an action
413 
                8'h0B : // Read Array
414 
                        begin
415 
                                $display("Opcode(%h) for Read Array received",read_data);
416 
                                rd_dummy = 1'b1;
417 
                                -> RA;
418 
                        end
419 
                8'h03 : // Read Array (low freq)
420 
                        begin
421 
                                $display("Opcode(%h) for Read Array (Low Freq) received",read_data);
422 
                                rd_dummy = 1'b0;
423 
                                -> RA;
424 
                        end
425 
                8'h20 : // Block erase 4 KB
426 
                        begin
427 
                                $display("Opcode(%h) for 4 KB Block erase received",read_data);
428 
                                -> BE4;
429 
                        end
430 
                8'h52 : // Block erase 32 KB
431 
                        begin
432 
                                $display("Opcode(%h) for 32 KB Block erase received",read_data);
433 
                                -> BE32;
434 
                        end
435 
                8'hD8 : // Block erase 64 KB
436 
                        begin
437 
                                $display("Opcode(%h) for 64 KB Block erase received",read_data);
438 
                                -> BE64;
439 
                        end
440 
                8'h60 : // Chip erase
441 
                        begin
442 
                                $display("Opcode(%h) for Chip erase received",read_data);
443 
                                -> CE;
444 
                        end
445 
                8'hC7 : // Chip erase
446 
                        begin
447 
                                $display("Opcode(%h) for Chip erase received",read_data);
448 
                                -> CE;
449 
                        end
450 
                8'h02 : // Byte Program
451 
                        begin
452 
                                $display("Opcode(%h) Byte Program received",read_data);
453 
                                -> BP;
454 
                        end
455 
                8'hAD : // Sequential Byte Program Mode Erase
456 
                        begin
457 
                                if(DEVICE=="AT25DF041A" || DEVICE=="AT26DF081A" || DEVICE=="AT26DF161A")
458 
                                begin
459 
                                        $display("Opcode(%h) Sequential Byte Program received",read_data);
460 
                                        -> SBP;
461 
                                end
462 
                                else if(DEVICE=="AT26DF321")
463 
                                        $display("Sequential Byte Program is not supported for device %s",DEVICE);
464 
                        end
465 
                8'hAF : // Sequential Byte Program Mode
466 
                        begin
467 
                                if(DEVICE=="AT25DF041A" || DEVICE=="AT26DF081A" || DEVICE=="AT26DF161A")
468 
                                begin
469 
                                        $display("Opcode(%h) Sequential Byte Program received",read_data);
470 
                                        -> SBP;
471 
                                end
472 
                                else if(DEVICE=="AT26DF321")
473 
                                        $display("Sequential Byte Program is not supported for device %s",DEVICE);
474 
                        end
475 
                8'h06 : // Write Enable
476 
                        begin
477 
                                $display("Opcode(%h) for Write Enable received",read_data);
478 
                                -> WE;
479 
                        end
480 
                8'h04 : // Write Disable
481 
                        begin
482 
                                $display("Opcode(%h) for Write Disable received",read_data);
483 
                                -> WD;
484 
                        end
485 
                8'h36 : // Protect Sector
486 
                        begin
487 
                                $display("Opcode(%h) for Protect Sector received",read_data);
488 
                                -> PS;
489 
                        end
490 
                8'h39 : // Unprotect Sector
491 
                        begin
492 
                                $display("Opcode(%h) for Unprotect Sector received",read_data);
493 
                                -> UPS;
494 
                        end
495 
                8'h3C : // Read Sector Protection Register
496 
                        begin
497 
                                $display("Opcode(%h) for Read Sector Protection Register received",read_data);
498 
                                -> RSPR;
499 
                        end
500 
                8'h05 : // Read Status Register
501 
                        begin
502 
                                $display("Opcode(%h) for Status Register Read received",read_data);
503 
                                -> RSR;
504 
                        end
505 
                8'h01 : // Write Status Register
506 
                        begin
507 
                                $display("Opcode(%h) for Write Status Register received",read_data);
508 
                                -> WSR;
509 
                        end
510 
                8'h9F : // Read Manufacturer and Device ID
511 
                        begin
512 
                                $display("Opcode(%h) for Read Manufacturer and Device ID received",read_data);
513 
                                -> MIR;
514 
                        end
515 
                8'hB9 : // Deep Power-down
516 
                        begin
517 
                                $display("Opcode(%h) for Deep Power-down received",read_data);
518 
                                -> EDPD;
519 
                        end
520 
                default :
521 
                begin
522 
                        $display ("Unrecognized opcode %h", read_data);
523 
                        disable get_opcode_;
524 
                end
525 
                endcase
526 
        end
527 
end
528 
 
529 
// *********************** TASKS / FUNCTIONS ************************** //
530 
 
531 
// get_opcode is a task to get 8 bits of opcode.
532 
// It obtains 8 bits of data obtained on SI
533 
task get_opcode;
534 
 
535 
integer i;
536 
begin
537 
        for (i=8; i>0; i = i-1)
538 
        begin
539 
                @(posedge SCK);
540 
                read_data[i-1] = SI;
541 
                if(HOLDB==1'b0)
542 
                        wait (HOLDB);
543 
        end
544 
        i=7;
545 
end
546 
endtask
547 
 
548 
// get_data is a task to get 8 bits of data. This data could be an address,
549 
// data or anything. It just obtains 8 bits of data obtained on SI
550 
task get_data;
551 
 
552 
integer i;
553 
begin
554 
        for (i=7; i>=0; i = i-1)
555 
        begin
556 
                @(posedge SCK);
557 
                read_data[i] = SI;
558 
                if(HOLDB==1'b0)
559 
                        wait (HOLDB);
560 
        end
561 
        i=7;
562 
end
563 
endtask
564 
 
565 
// task read_out_array is to read from main Memory
566 
task read_out_array ;
567 
input [23:0] read_addr;
568 
integer i;
569 
 
570 
begin
571 
        temp_data = memory [read_addr];
572 
        i = 7;
573 
        while (CSB == 1'b0) // continue transmitting, while, CSB is Low
574 
        begin
575 
                @(negedge SCK);
576 
                SO_reg = 1'bx;
577 
                if(HOLDB==1'b0)
578 
                begin
579 
                        #tHLQZ SO_on = 1'b0;
580 
                        wait (HOLDB);
581 
                        #tHHQX;
582 
                end
583 
                #tV SO_reg = temp_data[i];
584 
                SO_on = 1'b1;
585 
                if (i == 0)
586 
                begin
587 22 julius 
                        //$display ("Data: %h read from memory location %h",temp_data,read_addr);
588 15 unneback 
                        read_addr = read_addr + 1; // next byte
589 
                        i = 7;
590 
                        if (read_addr >= (MEMSIZE-1))
591 
                                read_addr = 0; // Note that rollover occurs at end of memory,
592 
                        temp_data = memory [read_addr];
593 
                end
594 
                else
595 
                        i = i - 1; // next bit
596 
        end // reading over, because CSB has gone high
597 
end
598 
endtask
599 
 
600 
// Sector protection
601 
task protect_sector;
602 
input [23:0] protect_address;
603 
 
604 
begin
605 
        $display("Entered Protect Sector task");
606 
 
607 
    if (DEVICE == "AT26DF321" && protect==1'b1)
608 
    begin
609 
        if(protect_address[23:16]==8'b00111111)
610 
                sector_reg[63] = 1'b1;
611 
        else if(protect_address[23:16]==8'b00111110)
612 
                sector_reg[62] = 1'b1;
613 
        else if(protect_address[23:16]==8'b00111101)
614 
                sector_reg[61] = 1'b1;
615 
        else if(protect_address[23:16]==8'b00111100)
616 
                sector_reg[60] = 1'b1;
617 
        else if(protect_address[23:16]==8'b00111011)
618 
                sector_reg[59] = 1'b1;
619 
        else if(protect_address[23:16]==8'b00111010)
620 
                sector_reg[58] = 1'b1;
621 
        else if(protect_address[23:16]==8'b00111001)
622 
                sector_reg[57] = 1'b1;
623 
        else if(protect_address[23:16]==8'b00111000)
624 
                sector_reg[56] = 1'b1;
625 
        else if(protect_address[23:16]==8'b00110111)
626 
                sector_reg[55] = 1'b1;
627 
        else if(protect_address[23:16]==8'b00110110)
628 
                sector_reg[54] = 1'b1;
629 
        else if(protect_address[23:16]==8'b00110101)
630 
                sector_reg[53] = 1'b1;
631 
        else if(protect_address[23:16]==8'b00110100)
632 
                sector_reg[52] = 1'b1;
633 
        else if(protect_address[23:16]==8'b00110011)
634 
                sector_reg[51] = 1'b1;
635 
        else if(protect_address[23:16]==8'b00110010)
636 
                sector_reg[50] = 1'b1;
637 
        else if(protect_address[23:16]==8'b00110001)
638 
                sector_reg[49] = 1'b1;
639 
        else if(protect_address[23:16]==8'b00110000)
640 
                sector_reg[48] = 1'b1;
641 
        else if(protect_address[23:16]==8'b00101111)
642 
                sector_reg[47] = 1'b1;
643 
        else if(protect_address[23:16]==8'b00101110)
644 
                sector_reg[46] = 1'b1;
645 
        else if(protect_address[23:16]==8'b00101101)
646 
                sector_reg[45] = 1'b1;
647 
        else if(protect_address[23:16]==8'b00101100)
648 
                sector_reg[44] = 1'b1;
649 
        else if(protect_address[23:16]==8'b00101011)
650 
                sector_reg[43] = 1'b1;
651 
        else if(protect_address[23:16]==8'b00101010)
652 
                sector_reg[42] = 1'b1;
653 
        else if(protect_address[23:16]==8'b00101001)
654 
                sector_reg[41] = 1'b1;
655 
        else if(protect_address[23:16]==8'b00101000)
656 
                sector_reg[40] = 1'b1;
657 
        else if(protect_address[23:16]==8'b00100111)
658 
                sector_reg[39] = 1'b1;
659 
        else if(protect_address[23:16]==8'b00100110)
660 
                sector_reg[38] = 1'b1;
661 
        else if(protect_address[23:16]==8'b00100101)
662 
                sector_reg[37] = 1'b1;
663 
        else if(protect_address[23:16]==8'b00100100)
664 
                sector_reg[36] = 1'b1;
665 
        else if(protect_address[23:16]==8'b00100011)
666 
                sector_reg[35] = 1'b1;
667 
        else if(protect_address[23:16]==8'b00100010)
668 
                sector_reg[34] = 1'b1;
669 
        else if(protect_address[23:16]==8'b00100001)
670 
                sector_reg[33] = 1'b1;
671 
        else if(protect_address[23:16]==8'b00100000)
672 
                sector_reg[32] = 1'b1;
673 
    end
674 
    if ((DEVICE == "AT26DF161A" || DEVICE == "AT26DF321") && protect==1'b1)
675 
    begin
676 
        if(protect_address[23:16]==8'b00011111)
677 
                sector_reg[31] = 1'b1;
678 
        else if(protect_address[23:16]==8'b00011110)
679 
                sector_reg[30] = 1'b1;
680 
        else if(protect_address[23:16]==8'b00011101)
681 
                sector_reg[29] = 1'b1;
682 
        else if(protect_address[23:16]==8'b00011100)
683 
                sector_reg[28] = 1'b1;
684 
        else if(protect_address[23:16]==8'b00011011)
685 
                sector_reg[27] = 1'b1;
686 
        else if(protect_address[23:16]==8'b00011010)
687 
                sector_reg[26] = 1'b1;
688 
        else if(protect_address[23:16]==8'b00011001)
689 
                sector_reg[25] = 1'b1;
690 
        else if(protect_address[23:16]==8'b00011000)
691 
                sector_reg[24] = 1'b1;
692 
        else if(protect_address[23:16]==8'b00010111)
693 
                sector_reg[23] = 1'b1;
694 
        else if(protect_address[23:16]==8'b00010110)
695 
                sector_reg[22] = 1'b1;
696 
        else if(protect_address[23:16]==8'b00010101)
697 
                sector_reg[21] = 1'b1;
698 
        else if(protect_address[23:16]==8'b00010100)
699 
                sector_reg[20] = 1'b1;
700 
        else if(protect_address[23:16]==8'b00010011)
701 
                sector_reg[19] = 1'b1;
702 
        else if(protect_address[23:16]==8'b00010010)
703 
                sector_reg[18] = 1'b1;
704 
        else if(protect_address[23:16]==8'b00010001)
705 
                sector_reg[17] = 1'b1;
706 
        else if(protect_address[23:16]==8'b00010000)
707 
                sector_reg[16] = 1'b1;
708 
    end
709 
 
710 
    if (DEVICE == "AT26DF081A" && protect==1'b1) // un-uniform sectors of AT26DF081A
711 
    begin
712 
        if(protect_address[23:14]==10'b00001111_00)
713 
                sector_reg[15] = 1'b1;
714 
        else if(protect_address[23:13]==11'b00001111_010)
715 
                sector_reg[16] = 1'b1;
716 
        else if(protect_address[23:13]==11'b00001111_011)
717 
                sector_reg[17] = 1'b1;
718 
        else if(protect_address[23:17]==9'b00001111_1)
719 
                sector_reg[18] = 1'b1;
720 
    end
721 
    else if ((DEVICE == "AT26DF161A" || DEVICE == "AT26DF321") && protect==1'b1)
722 
    begin
723 
        if(protect_address[23:16]==8'b00001111)
724 
                sector_reg[15] = 1'b1;
725 
    end
726 
 
727 
    if ((DEVICE == "AT26DF081A" || DEVICE == "AT26DF161A" || DEVICE == "AT26DF321") && protect==1'b1)
728 
    begin
729 
//      if(protect_address[23:16]==8'b00001111)
730 
//              sector_reg[15] = 1'b1;
731 
        if(protect_address[23:16]==8'b00001110)
732 
                sector_reg[14] = 1'b1;
733 
        else if(protect_address[23:16]==8'b00001101)
734 
                sector_reg[13] = 1'b1;
735 
        else if(protect_address[23:16]==8'b00001100)
736 
                sector_reg[12] = 1'b1;
737 
        else if(protect_address[23:16]==8'b00001011)
738 
                sector_reg[11] = 1'b1;
739 
        else if(protect_address[23:16]==8'b00001010)
740 
                sector_reg[10] = 1'b1;
741 
        else if(protect_address[23:16]==8'b00001001)
742 
                sector_reg[9] = 1'b1;
743 
        else if(protect_address[23:16]==8'b00001000)
744 
                sector_reg[8] = 1'b1;
745 
    end
746 
 
747 
    if (DEVICE == "AT25DF041A" && protect==1'b1) // un-uniform sectors of AT25DF041A
748 
    begin
749 
        if(protect_address[23:15]==9'b00000111_0)
750 
                sector_reg[7] = 1'b1;
751 
        else if(protect_address[23:13]==11'b00000111_100)
752 
                sector_reg[8] = 1'b1;
753 
        else if(protect_address[23:13]==11'b00000111_101)
754 
                sector_reg[9] = 1'b1;
755 
        else if(protect_address[23:14]==10'b00000111_11)
756 
                sector_reg[10] = 1'b1;
757 
    end
758 
    else if ((DEVICE == "AT26DF081A" || DEVICE == "AT26DF161A" || DEVICE == "AT26DF321") && protect==1'b1)
759 
        if(protect_address[23:16]==8'b00000111)
760 
                sector_reg[7] = 1'b1;
761 
 
762 
    if ((DEVICE == "AT25DF041A" || DEVICE == "AT26DF081A"
763 
        || DEVICE == "AT26DF161A" || DEVICE == "AT26DF321") && protect==1'b1)
764 
    begin
765 
//      if(protect_address[23:16]==8'b00000111)
766 
//              sector_reg[7] = 1'b1;
767 
        if(protect_address[23:16]==8'b00000110)
768 
                sector_reg[6] = 1'b1;
769 
        else if(protect_address[23:16]==8'b00000101)
770 
                sector_reg[5] = 1'b1;
771 
        else if(protect_address[23:16]==8'b00000100)
772 
                sector_reg[4] = 1'b1;
773 
        else if(protect_address[23:16]==8'b00000011)
774 
                sector_reg[3] = 1'b1;
775 
        else if(protect_address[23:16]==8'b00000010)
776 
                sector_reg[2] = 1'b1;
777 
        else if(protect_address[23:16]==8'b00000001)
778 
                sector_reg[1] = 1'b1;
779 
        else if(protect_address[23:16]==8'b00000000)
780 
                sector_reg[0] = 1'b1;
781 
    end
782 
end
783 
endtask
784 
 
785 
// Sector Unprotection
786 
task unprotect_sector;
787 
input [23:0] unprotect_address;
788 
begin
789 
    if ((DEVICE == "AT25DF041A") && unprotect==1'b1) // sectors of AT25DF041A
790 
    begin
791 
        $display("Entered Unprotect sector for Device: AT25DF041A");
792 
        if(unprotect_address[23:14]==10'b00000111_11)
793 
                sector_reg[10] = 1'b0;
794 
        else if(unprotect_address[23:13]==11'b00000111_101)
795 
                sector_reg[9] = 1'b0;
796 
        else if(unprotect_address[23:13]==11'b00000111_100)
797 
                sector_reg[8] = 1'b0;
798 
        else if(unprotect_address[23:15]==9'b00000111_0)
799 
                sector_reg[7] = 1'b0;
800 
        else if(unprotect_address[23:16]==8'b00000110)
801 
                sector_reg[6] = 1'b0;
802 
        else if(unprotect_address[23:16]==8'b00000101)
803 
                sector_reg[5] = 1'b0;
804 
        else if(unprotect_address[23:16]==8'b00000100)
805 
                sector_reg[4] = 1'b0;
806 
        else if(unprotect_address[23:16]==8'b00000011)
807 
                sector_reg[3] = 1'b0;
808 
        else if(unprotect_address[23:16]==8'b00000010)
809 
                sector_reg[2] = 1'b0;
810 
        else if(unprotect_address[23:16]==8'b00000001)
811 
                sector_reg[1] = 1'b0;
812 
        else if(unprotect_address[23:16]==8'b00000000)
813 
                sector_reg[0] = 1'b0;
814 
    end
815 
    else if (DEVICE == "AT26DF081A" && unprotect==1'b1) // sectors of AT26DF081A
816 
    begin
817 
        $display("Entered Unprotect sector for Device: AT26DF081A");
818 
        if(unprotect_address[23:17]==9'b00001111_1)
819 
                sector_reg[18] = 1'b0;
820 
        else if(unprotect_address[23:13]==11'b00001111_011)
821 
                sector_reg[17] = 1'b0;
822 
        else if(unprotect_address[23:13]==11'b00001111_010)
823 
                sector_reg[16] = 1'b0;
824 
        else if(unprotect_address[23:14]==10'b00001111_00)
825 
                sector_reg[15] = 1'b0;
826 
        else if(unprotect_address[23:16]==8'b00001110)
827 
                sector_reg[14] = 1'b0;
828 
        else if(unprotect_address[23:16]==8'b00001101)
829 
                sector_reg[13] = 1'b0;
830 
        else if(unprotect_address[23:16]==8'b00001100)
831 
                sector_reg[12] = 1'b0;
832 
        else if(unprotect_address[23:16]==8'b00001011)
833 
                sector_reg[11] = 1'b0;
834 
        else if(unprotect_address[23:16]==8'b00001010)
835 
                sector_reg[10] = 1'b0;
836 
        else if(unprotect_address[23:16]==8'b00001001)
837 
                sector_reg[9] = 1'b0;
838 
        else if(unprotect_address[23:16]==8'b00001000)
839 
                sector_reg[8] = 1'b0;
840 
        else if(unprotect_address[23:16]==8'b00000111)
841 
                sector_reg[7] = 1'b0;
842 
        else if(unprotect_address[23:16]==8'b00000110)
843 
                sector_reg[6] = 1'b0;
844 
        else if(unprotect_address[23:16]==8'b00000101)
845 
                sector_reg[5] = 1'b0;
846 
        else if(unprotect_address[23:16]==8'b00000100)
847 
                sector_reg[4] = 1'b0;
848 
        else if(unprotect_address[23:16]==8'b00000011)
849 
                sector_reg[3] = 1'b0;
850 
        else if(unprotect_address[23:16]==8'b00000010)
851 
                sector_reg[2] = 1'b0;
852 
        else if(unprotect_address[23:16]==8'b00000001)
853 
                sector_reg[1] = 1'b0;
854 
        else if(unprotect_address[23:16]==8'b00000000)
855 
                sector_reg[0] = 1'b0;
856 
    end
857 
    else if ((DEVICE == "AT26DF161A") && unprotect==1'b1) // sectors of AT26DF161A
858 
    begin
859 
        $display("Entered Unprotect sector for Device: AT26DF161A");
860 
        if(unprotect_address[23:16]==8'b00011111)
861 
                sector_reg[31] = 1'b0;
862 
        else if(unprotect_address[23:16]==8'b00011110)
863 
                sector_reg[30] = 1'b0;
864 
        else if(unprotect_address[23:16]==8'b00011101)
865 
                sector_reg[29] = 1'b0;
866 
        else if(unprotect_address[23:16]==8'b00011100)
867 
                sector_reg[28] = 1'b0;
868 
        else if(unprotect_address[23:16]==8'b00011011)
869 
                sector_reg[27] = 1'b0;
870 
        else if(unprotect_address[23:16]==8'b00011010)
871 
                sector_reg[26] = 1'b0;
872 
        else if(unprotect_address[23:16]==8'b00011001)
873 
                sector_reg[25] = 1'b0;
874 
        else if(unprotect_address[23:16]==8'b00011000)
875 
                sector_reg[24] = 1'b0;
876 
        else if(unprotect_address[23:16]==8'b00010111)
877 
                sector_reg[23] = 1'b0;
878 
        else if(unprotect_address[23:16]==8'b00010110)
879 
                sector_reg[22] = 1'b0;
880 
        else if(unprotect_address[23:16]==8'b00010101)
881 
                sector_reg[21] = 1'b0;
882 
        else if(unprotect_address[23:16]==8'b00010100)
883 
                sector_reg[20] = 1'b0;
884 
        else if(unprotect_address[23:16]==8'b00010011)
885 
                sector_reg[19] = 1'b0;
886 
        else if(unprotect_address[23:16]==8'b00010010)
887 
                sector_reg[18] = 1'b0;
888 
        else if(unprotect_address[23:16]==8'b00010001)
889 
                sector_reg[17] = 1'b0;
890 
        else if(unprotect_address[23:16]==8'b00010000)
891 
                sector_reg[16] = 1'b0;
892 
        else if(unprotect_address[23:16]==8'b00001111)
893 
                sector_reg[15] = 1'b0;
894 
        else if(unprotect_address[23:16]==8'b00001110)
895 
                sector_reg[14] = 1'b0;
896 
        else if(unprotect_address[23:16]==8'b00001101)
897 
                sector_reg[13] = 1'b0;
898 
        else if(unprotect_address[23:16]==8'b00001100)
899 
                sector_reg[12] = 1'b0;
900 
        else if(unprotect_address[23:16]==8'b00001011)
901 
                sector_reg[11] = 1'b0;
902 
        else if(unprotect_address[23:16]==8'b00001010)
903 
                sector_reg[10] = 1'b0;
904 
        else if(unprotect_address[23:16]==8'b00001001)
905 
                sector_reg[9] = 1'b0;
906 
        else if(unprotect_address[23:16]==8'b00001000)
907 
                sector_reg[8] = 1'b0;
908 
        else if(unprotect_address[23:16]==8'b00000111)
909 
                sector_reg[7] = 1'b0;
910 
        else if(unprotect_address[23:16]==8'b00000110)
911 
                sector_reg[6] = 1'b0;
912 
        else if(unprotect_address[23:16]==8'b00000101)
913 
                sector_reg[5] = 1'b0;
914 
        else if(unprotect_address[23:16]==8'b00000100)
915 
                sector_reg[4] = 1'b0;
916 
        else if(unprotect_address[23:16]==8'b00000011)
917 
                sector_reg[3] = 1'b0;
918 
        else if(unprotect_address[23:16]==8'b00000010)
919 
                sector_reg[2] = 1'b0;
920 
        else if(unprotect_address[23:16]==8'b00000001)
921 
                sector_reg[1] = 1'b0;
922 
        else if(unprotect_address[23:16]==8'b00000000)
923 
                sector_reg[0] = 1'b0;
924 
    end
925 
    else if (DEVICE == "AT26DF321" && unprotect==1'b1) // sectors of AT26DF321
926 
    begin
927 
        $display("Entered Unprotect sector for Device: AT26DF321");
928 
        if(unprotect_address[23:16]==8'b00111111)
929 
                sector_reg[63] = 1'b0;
930 
        else if(unprotect_address[23:16]==8'b00111110)
931 
                sector_reg[62] = 1'b0;
932 
        else if(unprotect_address[23:16]==8'b00111101)
933 
                sector_reg[61] = 1'b0;
934 
        else if(unprotect_address[23:16]==8'b00111100)
935 
                sector_reg[60] = 1'b0;
936 
        else if(unprotect_address[23:16]==8'b00111011)
937 
                sector_reg[59] = 1'b0;
938 
        else if(unprotect_address[23:16]==8'b00111010)
939 
                sector_reg[58] = 1'b0;
940 
        else if(unprotect_address[23:16]==8'b00111001)
941 
                sector_reg[57] = 1'b0;
942 
        else if(unprotect_address[23:16]==8'b00111000)
943 
                sector_reg[56] = 1'b0;
944 
        else if(unprotect_address[23:16]==8'b00110111)
945 
                sector_reg[55] = 1'b0;
946 
        else if(unprotect_address[23:16]==8'b00110110)
947 
                sector_reg[54] = 1'b0;
948 
        else if(unprotect_address[23:16]==8'b00110101)
949 
                sector_reg[53] = 1'b0;
950 
        else if(unprotect_address[23:16]==8'b00110100)
951 
                sector_reg[52] = 1'b0;
952 
        else if(unprotect_address[23:16]==8'b00110011)
953 
                sector_reg[51] = 1'b0;
954 
        else if(unprotect_address[23:16]==8'b00110010)
955 
                sector_reg[50] = 1'b0;
956 
        else if(unprotect_address[23:16]==8'b00110001)
957 
                sector_reg[49] = 1'b0;
958 
        else if(unprotect_address[23:16]==8'b00110000)
959 
                sector_reg[48] = 1'b0;
960 
        else if(unprotect_address[23:16]==8'b00101111)
961 
                sector_reg[47] = 1'b0;
962 
        else if(unprotect_address[23:16]==8'b00101110)
963 
                sector_reg[46] = 1'b0;
964 
        else if(unprotect_address[23:16]==8'b00101101)
965 
                sector_reg[45] = 1'b0;
966 
        else if(unprotect_address[23:16]==8'b00101100)
967 
                sector_reg[44] = 1'b0;
968 
        else if(unprotect_address[23:16]==8'b00101011)
969 
                sector_reg[43] = 1'b0;
970 
        else if(unprotect_address[23:16]==8'b00101010)
971 
                sector_reg[42] = 1'b0;
972 
        else if(unprotect_address[23:16]==8'b00101001)
973 
                sector_reg[41] = 1'b0;
974 
        else if(unprotect_address[23:16]==8'b00101000)
975 
                sector_reg[40] = 1'b0;
976 
        else if(unprotect_address[23:16]==8'b00100111)
977 
                sector_reg[39] = 1'b0;
978 
        else if(unprotect_address[23:16]==8'b00100110)
979 
                sector_reg[38] = 1'b0;
980 
        else if(unprotect_address[23:16]==8'b00100101)
981 
                sector_reg[37] = 1'b0;
982 
        else if(unprotect_address[23:16]==8'b00100100)
983 
                sector_reg[36] = 1'b0;
984 
        else if(unprotect_address[23:16]==8'b00100011)
985 
                sector_reg[35] = 1'b0;
986 
        else if(unprotect_address[23:16]==8'b00100010)
987 
                sector_reg[34] = 1'b0;
988 
        else if(unprotect_address[23:16]==8'b00100001)
989 
                sector_reg[33] = 1'b0;
990 
        else if(unprotect_address[23:16]==8'b00100000)
991 
                sector_reg[32] = 1'b0;
992 
        else if(unprotect_address[23:16]==8'b00011111)
993 
                sector_reg[31] = 1'b0;
994 
        else if(unprotect_address[23:16]==8'b00011110)
995 
                sector_reg[30] = 1'b0;
996 
        else if(unprotect_address[23:16]==8'b00011101)
997 
                sector_reg[29] = 1'b0;
998 
        else if(unprotect_address[23:16]==8'b00011100)
999 
                sector_reg[28] = 1'b0;
1000 
        else if(unprotect_address[23:16]==8'b00011011)
1001 
                sector_reg[27] = 1'b0;
1002 
        else if(unprotect_address[23:16]==8'b00011010)
1003 
                sector_reg[26] = 1'b0;
1004 
        else if(unprotect_address[23:16]==8'b00011001)
1005 
                sector_reg[25] = 1'b0;
1006 
        else if(unprotect_address[23:16]==8'b00011000)
1007 
                sector_reg[24] = 1'b0;
1008 
        else if(unprotect_address[23:16]==8'b00010111)
1009 
                sector_reg[23] = 1'b0;
1010 
        else if(unprotect_address[23:16]==8'b00010110)
1011 
                sector_reg[22] = 1'b0;
1012 
        else if(unprotect_address[23:16]==8'b00010101)
1013 
                sector_reg[21] = 1'b0;
1014 
        else if(unprotect_address[23:16]==8'b00010100)
1015 
                sector_reg[20] = 1'b0;
1016 
        else if(unprotect_address[23:16]==8'b00010011)
1017 
                sector_reg[19] = 1'b0;
1018 
        else if(unprotect_address[23:16]==8'b00010010)
1019 
                sector_reg[18] = 1'b0;
1020 
        else if(unprotect_address[23:16]==8'b00010001)
1021 
                sector_reg[17] = 1'b0;
1022 
        else if(unprotect_address[23:16]==8'b00010000)
1023 
                sector_reg[16] = 1'b0;
1024 
        else if(unprotect_address[23:16]==8'b00001111)
1025 
                sector_reg[15] = 1'b0;
1026 
        else if(unprotect_address[23:16]==8'b00001110)
1027 
                sector_reg[14] = 1'b0;
1028 
        else if(unprotect_address[23:16]==8'b00001101)
1029 
                sector_reg[13] = 1'b0;
1030 
        else if(unprotect_address[23:16]==8'b00001100)
1031 
                sector_reg[12] = 1'b0;
1032 
        else if(unprotect_address[23:16]==8'b00001011)
1033 
                sector_reg[11] = 1'b0;
1034 
        else if(unprotect_address[23:16]==8'b00001010)
1035 
                sector_reg[10] = 1'b0;
1036 
        else if(unprotect_address[23:16]==8'b00001001)
1037 
                sector_reg[9] = 1'b0;
1038 
        else if(unprotect_address[23:16]==8'b00001000)
1039 
                sector_reg[8] = 1'b0;
1040 
        else if(unprotect_address[23:16]==8'b00000111)
1041 
                sector_reg[7] = 1'b0;
1042 
        else if(unprotect_address[23:16]==8'b00000110)
1043 
                sector_reg[6] = 1'b0;
1044 
        else if(unprotect_address[23:16]==8'b00000101)
1045 
                sector_reg[5] = 1'b0;
1046 
        else if(unprotect_address[23:16]==8'b00000100)
1047 
                sector_reg[4] = 1'b0;
1048 
        else if(unprotect_address[23:16]==8'b00000011)
1049 
                sector_reg[3] = 1'b0;
1050 
        else if(unprotect_address[23:16]==8'b00000010)
1051 
                sector_reg[2] = 1'b0;
1052 
        else if(unprotect_address[23:16]==8'b00000001)
1053 
                sector_reg[1] = 1'b0;
1054 
        else if(unprotect_address[23:16]==8'b00000000)
1055 
                sector_reg[0] = 1'b0;
1056 
    end
1057 
        else
1058 
        $display("Unprotect Sector failed");
1059 
 
1060 
end
1061 
endtask
1062 
 
1063 
// Check Sector Protection
1064 
task check_protection;
1065 
input [23:0] check_address;
1066 
begin
1067 
    if (DEVICE == "AT26DF321")
1068 
    begin
1069 
        if((check_address[23:16]==8'b00111111 && sector_reg[63]==1'b1)
1070 
        || (check_address[23:16]==8'b00111110 && sector_reg[62]==1'b1)
1071 
        || (check_address[23:16]==8'b00111101 && sector_reg[61]==1'b1)
1072 
        || (check_address[23:16]==8'b00111100 && sector_reg[60]==1'b1)
1073 
        || (check_address[23:16]==8'b00111011 && sector_reg[59]==1'b1)
1074 
        || (check_address[23:16]==8'b00111010 && sector_reg[58]==1'b1)
1075 
        || (check_address[23:16]==8'b00111001 && sector_reg[57]==1'b1)
1076 
        || (check_address[23:16]==8'b00111000 && sector_reg[56]==1'b1)
1077 
        || (check_address[23:16]==8'b00110111 && sector_reg[55]==1'b1)
1078 
        || (check_address[23:16]==8'b00110110 && sector_reg[54]==1'b1)
1079 
        || (check_address[23:16]==8'b00110101 && sector_reg[53]==1'b1)
1080 
        || (check_address[23:16]==8'b00110100 && sector_reg[52]==1'b1)
1081 
        || (check_address[23:16]==8'b00110011 && sector_reg[51]==1'b1)
1082 
        || (check_address[23:16]==8'b00110010 && sector_reg[50]==1'b1)
1083 
        || (check_address[23:16]==8'b00110001 && sector_reg[49]==1'b1)
1084 
        || (check_address[23:16]==8'b00110000 && sector_reg[48]==1'b1)
1085 
        || (check_address[23:16]==8'b00101111 && sector_reg[47]==1'b1)
1086 
        || (check_address[23:16]==8'b00101110 && sector_reg[46]==1'b1)
1087 
        || (check_address[23:16]==8'b00101101 && sector_reg[45]==1'b1)
1088 
        || (check_address[23:16]==8'b00101100 && sector_reg[44]==1'b1)
1089 
        || (check_address[23:16]==8'b00101011 && sector_reg[43]==1'b1)
1090 
        || (check_address[23:16]==8'b00101010 && sector_reg[42]==1'b1)
1091 
        || (check_address[23:16]==8'b00101001 && sector_reg[41]==1'b1)
1092 
        || (check_address[23:16]==8'b00101000 && sector_reg[40]==1'b1)
1093 
        || (check_address[23:16]==8'b00100111 && sector_reg[39]==1'b1)
1094 
        || (check_address[23:16]==8'b00100110 && sector_reg[38]==1'b1)
1095 
        || (check_address[23:16]==8'b00100101 && sector_reg[37]==1'b1)
1096 
        || (check_address[23:16]==8'b00100100 && sector_reg[36]==1'b1)
1097 
        || (check_address[23:16]==8'b00100011 && sector_reg[35]==1'b1)
1098 
        || (check_address[23:16]==8'b00100010 && sector_reg[34]==1'b1)
1099 
        || (check_address[23:16]==8'b00100001 && sector_reg[33]==1'b1)
1100 
        || (check_address[23:16]==8'b00100000 && sector_reg[32]==1'b1)
1101 
        || (check_address[23:16]==8'b00011111 && sector_reg[31]==1'b1)
1102 
        || (check_address[23:16]==8'b00011110 && sector_reg[30]==1'b1)
1103 
        || (check_address[23:16]==8'b00011101 && sector_reg[29]==1'b1)
1104 
        || (check_address[23:16]==8'b00011100 && sector_reg[28]==1'b1)
1105 
        || (check_address[23:16]==8'b00011011 && sector_reg[27]==1'b1)
1106 
        || (check_address[23:16]==8'b00011010 && sector_reg[26]==1'b1)
1107 
        || (check_address[23:16]==8'b00011001 && sector_reg[25]==1'b1)
1108 
        || (check_address[23:16]==8'b00011000 && sector_reg[24]==1'b1)
1109 
        || (check_address[23:16]==8'b00010111 && sector_reg[23]==1'b1)
1110 
        || (check_address[23:16]==8'b00010110 && sector_reg[22]==1'b1)
1111 
        || (check_address[23:16]==8'b00010101 && sector_reg[21]==1'b1)
1112 
        || (check_address[23:16]==8'b00010100 && sector_reg[20]==1'b1)
1113 
        || (check_address[23:16]==8'b00010011 && sector_reg[19]==1'b1)
1114 
        || (check_address[23:16]==8'b00010010 && sector_reg[18]==1'b1)
1115 
        || (check_address[23:16]==8'b00010001 && sector_reg[17]==1'b1)
1116 
        || (check_address[23:16]==8'b00010000 && sector_reg[16]==1'b1)
1117 
        || (check_address[23:16]==8'b00001111 && sector_reg[15]==1'b1)
1118 
        || (check_address[23:16]==8'b00001110 && sector_reg[14]==1'b1)
1119 
        || (check_address[23:16]==8'b00001101 && sector_reg[13]==1'b1)
1120 
        || (check_address[23:16]==8'b00001100 && sector_reg[12]==1'b1)
1121 
        || (check_address[23:16]==8'b00001011 && sector_reg[11]==1'b1)
1122 
        || (check_address[23:16]==8'b00001010 && sector_reg[10]==1'b1)
1123 
        || (check_address[23:16]==8'b00001001 && sector_reg[9] ==1'b1)
1124 
        || (check_address[23:16]==8'b00001000 && sector_reg[8] ==1'b1)
1125 
        || (check_address[23:16]==8'b00000111 && sector_reg[7] ==1'b1)
1126 
        || (check_address[23:16]==8'b00000110 && sector_reg[6] ==1'b1)
1127 
        || (check_address[23:16]==8'b00000101 && sector_reg[5] ==1'b1)
1128 
        || (check_address[23:16]==8'b00000100 && sector_reg[4] ==1'b1)
1129 
        || (check_address[23:16]==8'b00000011 && sector_reg[3] ==1'b1)
1130 
        || (check_address[23:16]==8'b00000010 && sector_reg[2] ==1'b1)
1131 
        || (check_address[23:16]==8'b00000001 && sector_reg[1] ==1'b1)
1132 
        || (check_address[23:16]==8'b00000000 && sector_reg[0] ==1'b1))
1133 
                protected = 1'b1;
1134 
        else
1135 
                protected = 1'b0;
1136 
    end
1137 
    else if (DEVICE == "AT26DF161A")
1138 
    begin
1139 
        if((check_address[23:16]==8'b00011111 && sector_reg[31]==1'b1)
1140 
        || (check_address[23:16]==8'b00011110 && sector_reg[30]==1'b1)
1141 
        || (check_address[23:16]==8'b00011101 && sector_reg[29]==1'b1)
1142 
        || (check_address[23:16]==8'b00011100 && sector_reg[28]==1'b1)
1143 
        || (check_address[23:16]==8'b00011011 && sector_reg[27]==1'b1)
1144 
        || (check_address[23:16]==8'b00011010 && sector_reg[26]==1'b1)
1145 
        || (check_address[23:16]==8'b00011001 && sector_reg[25]==1'b1)
1146 
        || (check_address[23:16]==8'b00011000 && sector_reg[24]==1'b1)
1147 
        || (check_address[23:16]==8'b00010111 && sector_reg[23]==1'b1)
1148 
        || (check_address[23:16]==8'b00010110 && sector_reg[22]==1'b1)
1149 
        || (check_address[23:16]==8'b00010101 && sector_reg[21]==1'b1)
1150 
        || (check_address[23:16]==8'b00010100 && sector_reg[20]==1'b1)
1151 
        || (check_address[23:16]==8'b00010011 && sector_reg[19]==1'b1)
1152 
        || (check_address[23:16]==8'b00010010 && sector_reg[18]==1'b1)
1153 
        || (check_address[23:16]==8'b00010001 && sector_reg[17]==1'b1)
1154 
        || (check_address[23:16]==8'b00010000 && sector_reg[16]==1'b1)
1155 
        || (check_address[23:16]==8'b00001111 && sector_reg[15]==1'b1)
1156 
        || (check_address[23:16]==8'b00001110 && sector_reg[14]==1'b1)
1157 
        || (check_address[23:16]==8'b00001101 && sector_reg[13]==1'b1)
1158 
        || (check_address[23:16]==8'b00001100 && sector_reg[12]==1'b1)
1159 
        || (check_address[23:16]==8'b00001011 && sector_reg[11]==1'b1)
1160 
        || (check_address[23:16]==8'b00001010 && sector_reg[10]==1'b1)
1161 
        || (check_address[23:16]==8'b00001001 && sector_reg[9] ==1'b1)
1162 
        || (check_address[23:16]==8'b00001000 && sector_reg[8] ==1'b1)
1163 
        || (check_address[23:16]==8'b00000111 && sector_reg[7] ==1'b1)
1164 
        || (check_address[23:16]==8'b00000110 && sector_reg[6] ==1'b1)
1165 
        || (check_address[23:16]==8'b00000101 && sector_reg[5] ==1'b1)
1166 
        || (check_address[23:16]==8'b00000100 && sector_reg[4] ==1'b1)
1167 
        || (check_address[23:16]==8'b00000011 && sector_reg[3] ==1'b1)
1168 
        || (check_address[23:16]==8'b00000010 && sector_reg[2] ==1'b1)
1169 
        || (check_address[23:16]==8'b00000001 && sector_reg[1] ==1'b1)
1170 
        || (check_address[23:16]==8'b00000000 && sector_reg[0] ==1'b1))
1171 
                protected = 1'b1;
1172 
        else
1173 
                protected = 1'b0;
1174 
    end
1175 
    else if (DEVICE == "AT26DF081A") // un-uniform sectors of AT26DF081A
1176 
    begin
1177 
        if((check_address[23:17]==9'b00001111_1 && sector_reg[18]   ==1'b1)
1178 
        || (check_address[23:13]==11'b00001111_011 && sector_reg[17]==1'b1)
1179 
        || (check_address[23:13]==11'b00001111_010 && sector_reg[16]==1'b1)
1180 
        || (check_address[23:14]==10'b00001111_00 && sector_reg[15] ==1'b1)
1181 
        || (check_address[23:16]==8'b00001110 && sector_reg[14]==1'b1)
1182 
        || (check_address[23:16]==8'b00001101 && sector_reg[13]==1'b1)
1183 
        || (check_address[23:16]==8'b00001100 && sector_reg[12]==1'b1)
1184 
        || (check_address[23:16]==8'b00001011 && sector_reg[11]==1'b1)
1185 
        || (check_address[23:16]==8'b00001010 && sector_reg[10]==1'b1)
1186 
        || (check_address[23:16]==8'b00001001 && sector_reg[9] ==1'b1)
1187 
        || (check_address[23:16]==8'b00001000 && sector_reg[8] ==1'b1)
1188 
        || (check_address[23:16]==8'b00000111 && sector_reg[7] ==1'b1)
1189 
        || (check_address[23:16]==8'b00000110 && sector_reg[6] ==1'b1)
1190 
        || (check_address[23:16]==8'b00000101 && sector_reg[5] ==1'b1)
1191 
        || (check_address[23:16]==8'b00000100 && sector_reg[4] ==1'b1)
1192 
        || (check_address[23:16]==8'b00000011 && sector_reg[3] ==1'b1)
1193 
        || (check_address[23:16]==8'b00000010 && sector_reg[2] ==1'b1)
1194 
        || (check_address[23:16]==8'b00000001 && sector_reg[1] ==1'b1)
1195 
        || (check_address[23:16]==8'b00000000 && sector_reg[0] ==1'b1))
1196 
                protected = 1'b1;
1197 
        else
1198 
                protected = 1'b0;
1199 
    end
1200 
    else if (DEVICE == "AT25DF041A") // un-uniform sectors of AT25DF041A
1201 
    begin
1202 
        if((check_address[23:14]==10'b00000111_11 && sector_reg[10]==1'b1)
1203 
        || (check_address[23:13]==11'b00000111_101 && sector_reg[9]==1'b1)
1204 
        || (check_address[23:13]==11'b00000111_100 && sector_reg[8]==1'b1)
1205 
        || (check_address[23:15]==9'b00000111_0 && sector_reg[7]   ==1'b1)
1206 
        || (check_address[23:16]==8'b00000110 && sector_reg[6]==1'b1)
1207 
        || (check_address[23:16]==8'b00000101 && sector_reg[5]==1'b1)
1208 
        || (check_address[23:16]==8'b00000100 && sector_reg[4]==1'b1)
1209 
        || (check_address[23:16]==8'b00000011 && sector_reg[3]==1'b1)
1210 
        || (check_address[23:16]==8'b00000010 && sector_reg[2]==1'b1)
1211 
        || (check_address[23:16]==8'b00000001 && sector_reg[1]==1'b1)
1212 
        || (check_address[23:16]==8'b00000000 && sector_reg[0]==1'b1))
1213 
                protected = 1'b1;
1214 
        else
1215 
                protected = 1'b0;
1216 
    end
1217 
        else
1218 
        $display("Check Sector Protection failed");
1219 
end
1220 
endtask
1221 
 
1222 
// Sending Sector Protection status
1223 
task send_protection_status;
1224 
integer local_i;
1225 
reg [7:0] send_status;   // status value, 'ff' if protected, '00' if unprotected
1226 
begin
1227 
        if(protected==1'b1)
1228 
                send_status = 8'hff;
1229 
        else
1230 
                send_status = 8'h00;
1231 
        local_i = 7;
1232 
 
1233 
        while (CSB == 1'b0) // continue transmitting, while, CSB is Low
1234 
        begin
1235 
                @(negedge SCK);
1236 
                SO_reg = 1'bx;
1237 
                if(HOLDB==1'b0)
1238 
                begin
1239 
                        #tHLQZ SO_on = 1'b0;
1240 
                        wait (HOLDB);
1241 
                        #tHHQX;
1242 
                end
1243 
                #tV;
1244 
                SO_reg = send_status[local_i];
1245 
                SO_on = 1'b1;
1246 
                if (local_i == 0)
1247 
                        local_i = 7;
1248 
                else
1249 
                        local_i = local_i - 1; // next bit
1250 
        end // sending status over, because CSB has gone high
1251 
end
1252 
endtask
1253 
 
1254 
// receive data for byte/page programming
1255 
task page_program;
1256 
begin
1257 
        pp_j = 0;
1258 
        while(CSB==1'b0)
1259 
        begin
1260 
                for (pp_i=8; pp_i>0; pp_i = pp_i-1)
1261 
                begin
1262 
                        @(posedge SCK);
1263 
                        read_data[pp_i-1] = SI;
1264 
                        if(HOLDB==1'b0)
1265 
                                wait (HOLDB);
1266 
                end
1267 
                int_buffer[pp_j] = read_data;
1268 
                pp_j = pp_j+1;
1269 
        $display("One byte of data: %h received for Page Program",read_data);
1270 
        end
1271 
end
1272 
endtask
1273 
 
1274 
// Byte program for devices. also used for page program
1275 
task byte_program;
1276 
input [23:0] write_address;
1277 
input [7:0] write_data;
1278 
begin
1279 
        memory [write_address] = write_data;
1280 
        $display ("One Byte of data %h written in memory in location %h", write_data, write_address);
1281 
end
1282 
endtask
1283 
 
1284 
// Erase a 4kB block
1285 
task erase_4kb;
1286 
input [23:0] erase_address;
1287 
 
1288 
reg [11:0] erase4_i;
1289 
reg [23:0] block_addr4;
1290 
 
1291 
begin
1292 
        block_addr4 = {erase_address[23:12],12'b0000_0000_0000};
1293 
        $display ("4kB Block with start address %h is going to be erased", block_addr4);
1294 
 
1295 
        for(erase4_i=12'b0; erase4_i < 12'b1111_1111_1111; erase4_i=erase4_i+1)
1296 
        begin
1297 
                memory [block_addr4 + erase4_i] = 8'hff;
1298 
        end
1299 
end
1300 
endtask
1301 
 
1302 
// Erase a 32kB block
1303 
task erase_32kb;
1304 
input [23:0] erase_address;
1305 
 
1306 
reg [14:0] erase32_i;
1307 
reg [23:0] block_addr32;
1308 
 
1309 
begin
1310 
        block_addr32 = {erase_address[23:15],15'b0000_0000_0000_000};
1311 
        $display ("32kB Block with start address %h is going to be erased", block_addr32);
1312 
 
1313 
        for(erase32_i=15'b0; erase32_i < 15'b1111_1111_1111_111; erase32_i=erase32_i+1)
1314 
        begin
1315 
                memory [block_addr32 + erase32_i] = 8'hff;
1316 
        end
1317 
end
1318 
endtask
1319 
 
1320 
// Erase a 64kB block
1321 
task erase_64kb;
1322 
input [23:0] erase_address;
1323 
 
1324 
reg [15:0] erase64_i;
1325 
reg [23:0] block_addr64;
1326 
 
1327 
begin
1328 
        block_addr64 = {erase_address[23:16],16'b0000_0000_0000_0000};
1329 
        $display ("64kB Block with start address %h is going to be erased", block_addr64);
1330 
 
1331 
        for(erase64_i=0; erase64_i < 16'b1111_1111_1111_1111; erase64_i=erase64_i+1)
1332 
        begin
1333 
                memory [block_addr64 + erase64_i] = 8'hff;
1334 
        end
1335 
end
1336 
endtask
1337 
 
1338 
// Chip Erase
1339 
task erase_chip;
1340 
 
1341 
reg [23:0] erase_i;
1342 
 
1343 
begin
1344 
        $display ("Chip Erase is going to be started");
1345 
        for(erase_i=0; erase_i < (MEMSIZE-1); erase_i=erase_i+1)
1346 
        begin
1347 
                memory [erase_i] = 8'hff;
1348 
        end
1349 
end
1350 
endtask
1351 
 
1352 
// ******************* Execution of Opcodes ********************* //
1353 
 
1354 
// ************* Deep Power-down ***************** //
1355 
always @(EDPD)
1356 
begin : EDPD_
1357 
        if (RDYnBSY == 1'b1) // device is already busy
1358 
        begin
1359 
                $display ("Device is busy. Deep Power-down command cannot be issued");
1360 
                disable EDPD_ ;
1361 
        end
1362 
        // if it comes here, means, the above if was false.
1363 
 
1364 22 julius 
   //if (freq_error==1'b1)
1365 
        //$display("WARNING: Frequency should be less than %d Mhz for SPI interface. Deep Power-down is not allowed.",fSCK);
1366 15 unneback 
 
1367 
        @ (posedge CSB);
1368 
        RDYnBSY = 1'b1;
1369 
        #tEDPD deep_power_down = 1'b1;
1370 
        RDYnBSY = 1'b0;
1371 
        $display ("Device %s enters into Deep Power-down mode. Send 'Resume from Deep Power-down' to resume", DEVICE);
1372 
end
1373 
 
1374 
// ************* Resume from Deep Power-down ***************** //
1375 
always @(RDPD)
1376 
begin : RDPD_
1377 
        if (RDYnBSY == 1'b1) // device is already busy
1378 
        begin
1379 
                $display ("Device is busy. Deep Power-down command cannot be issued");
1380 
                disable EDPD_ ;
1381 
        end
1382 
        // if it comes here, means, the above if was false.
1383 
 
1384 22 julius 
   //if (freq_error==1'b1)
1385 
        //$display("WARNING: Frequency should be less than %d Mhz for SPI interface. Resume from Deep Power-down is not allowed.",fSCK);
1386 15 unneback 
 
1387 
        @ (posedge CSB);
1388 
        RDYnBSY = 1'b1;
1389 
        #tRDPD deep_power_down = 1'b0;
1390 
        RDYnBSY = 1'b0;
1391 
        $display ("Device %s Resumes from Deep Power-down mode", DEVICE);
1392 
end
1393 
 
1394 
// ************* Manufacturing ID Read ******************** //
1395 
always @(MIR)
1396 
begin: MIR_
1397 
        if (RDYnBSY == 1'b1) // device is already busy
1398 
        begin
1399 
                $display ("Device is busy. Manufacturing ID Read cannot be issued");
1400 
                disable EDPD_ ;
1401 
        end
1402 
        // if it comes here, means, the above if was false.
1403 
 
1404 22 julius 
   //if (freq_error==1'b1)
1405 
        //$display("WARNING: Frequency should be less than %d Mhz for SPI interface. Manufacturing ID Read is not allowed.",fSCK);
1406 15 unneback 
 
1407 
        j = 32;
1408 
        while (CSB == 1'b0)
1409 
        begin
1410 
                @(negedge SCK);
1411 
                SO_reg = 1'bx;
1412 
                if(HOLDB==1'b0)
1413 
                begin
1414 
                        #tHLQZ SO_on = 1'b0;
1415 
                        wait (HOLDB);
1416 
                        #tHHQX;
1417 
                end
1418 
                #tV;
1419 
                if (j > 0)
1420 
                begin
1421 
                        SO_reg = MAN_ID[j-1];
1422 
                        j = j-1;
1423 
                        SO_on = 1'b1;
1424 
                        if(j == 0)
1425 
                        begin
1426 
                                $display ("Manufacture ID and Device ID of Device %s sent", DEVICE);
1427 
                                j = 32;
1428 
                        end
1429 
                end
1430 
        end // output next bit on next falling edge of SCK
1431 
        $display ("Manufacture ID and Device ID of Device %s sent", DEVICE);
1432 
end
1433 
 
1434 
// ************ Read Status Register ******************** //
1435 
always @(RSR)
1436 
begin: RSR_
1437 22 julius 
   //if (freq_error==1'b1)
1438 
        //$display("WARNING: Frequency should be less than %d Mhz for SPI interface. Status Register Read is not allowed.",fSCK);
1439 15 unneback 
 
1440 
        status_read = 1'b1; // reading status_reg
1441 
        j = 8;
1442 
        while (CSB == 1'b0)
1443 
        begin
1444 
                @(negedge SCK);
1445 
                SO_reg = 1'bx;
1446 
                if(HOLDB==1'b0)
1447 
                begin
1448 
                        #tHLQZ SO_on = 1'b0;
1449 
                        wait (HOLDB);
1450 
                        #tHHQX;
1451 
                end
1452 
                #tV;
1453 
                if (j > 0)
1454 
                begin
1455 
                        SO_on = 1'b1;
1456 
                        SO_reg = status_reg[j-1];
1457 
                        j = j-1;
1458 
                        if (j == 0)
1459 
                        begin
1460 
                                j = 8;
1461 
                                $display ("Status register content of Device %s transmitted", DEVICE);
1462 
                        end
1463 
                end
1464 
        end // output next bit on next falling edge of SCK
1465 
        status_read = 1'b0; // status_reg read is over
1466 
end
1467 
 
1468 
// ************ Write Status Register ******************** //
1469 
always @(WSR)
1470 
begin : WSR_
1471 
        if (RDYnBSY == 1'b1) // device is already busy
1472 
        begin
1473 
                $display ("Device %s is busy. Write Status Register is not allowed", DEVICE);
1474 
                disable WSR_;
1475 
        end
1476 
        // if it comes here, means, the above if was false.
1477 
 
1478 
   if (freq_error==1'b1)
1479 
        $display("WARNING: Frequency should be less than %d Mhz for SPI interface. Write Status Register is not allowed.",fSCK);
1480 
 
1481 
        get_data;
1482 
        SPRL_val = read_data [7];
1483 
        stat_reg_temp = read_data [5:2];
1484 
 
1485 
        @ (posedge CSB);
1486 
        if(WEL==1'b1)
1487 
        begin
1488 
                if(WPB==1'b0 && SPRL==1'b0 && SPRL_val==1'b1)
1489 
                        $display("SPRL Hardware locked");
1490 
                else if(WPB==1'b1 && SPRL==1'b0 && SPRL_val==1'b1)
1491 
                        $display("SPRL Software locked");
1492 
                else if(WPB==1'b0 && SPRL==1'b1 && SPRL_val==1'b1)
1493 
                        $display("SPRL Hardware locked. Lock cannot be done");
1494 
                else if(WPB==1'b1 && SPRL==1'b1 && SPRL_val==1'b1)
1495 
                        $display("SPRL Software locked. Lock cannot be done");
1496 
                else if(WPB==1'b0 && SPRL==1'b1 && SPRL_val==1'b0)
1497 
                        $display("SPRL Hardware locked. Unlock cannot be done");
1498 
                else if(WPB==1'b1 && SPRL==1'b1 && SPRL_val==1'b0)
1499 
                        $display("Sector Protection Register UnLocked");
1500 
                else
1501 
                        $display("SPRL in unlocked state");
1502 
 
1503 
                if(stat_reg_temp==4'b1111 && SPRL==1'b0)
1504 
                        global_protect = 1'b1;
1505 
                else if(stat_reg_temp==4'b0000 && SPRL==1'b0)
1506 
                        global_unprotect = 1'b1;
1507 
                else if(SPRL==1'b1 && (stat_reg_temp==4'b0000 || stat_reg_temp==4'b1111))
1508 
                begin
1509 
                        $display("SPRL locked. Global Protect/Unprotect cannot be done");
1510 
                        global_protect = 1'b0;
1511 
                        global_unprotect = 1'b0;
1512 
                end
1513 
 
1514 
                if(SPRL==1'b0 && global_protect==1'b1)
1515 
                        $display("Global Protection issued for Sector protection register");
1516 
                else if(SPRL==1'b0 && global_unprotect==1'b1)
1517 
                        $display("Global Unprotect issued for Sector protection register");
1518 
                else if(SPRL==1'b1 && (global_protect==1'b1 || global_unprotect==1'b1))
1519 
                        $display("SPRL locked. Global Protect/Unprotect cannot be done");
1520 
 
1521 
                if(SPRL==1'b0 && SPRL_val==1'b1)
1522 
                begin
1523 
                        RDYnBSY = 1'b1;
1524 
                        lock = 1'b1;
1525 
                        #tWRSR;
1526 
                end
1527 
                else if(SPRL==1'b1 && SPRL_val==1'b0)
1528 
                begin
1529 
                        RDYnBSY = 1'b1;
1530 
                        unlock = 1'b1;
1531 
                        #tWRSR;
1532 
                end
1533 
                else if(global_protect==1'b1 || global_unprotect==1'b1)
1534 
                begin
1535 
                        RDYnBSY = 1'b1;
1536 
                        #tWRSR;
1537 
                end
1538 
        end
1539 
        else
1540 
                $display ("WEL bit not set. Write Status Register is not allowed");
1541 
 
1542 
        lock = 1'b0;
1543 
        unlock = 1'b0;
1544 
        RDYnBSY = 1'b0;
1545 
        global_protect = 1'b0;
1546 
        global_unprotect = 1'b0;
1547 
        WEL = 1'b0;
1548 
        $display ("Write Status Register operation completed");
1549 
end
1550 
 
1551 
// ************ Write Enable ******************** //
1552 
always @(WE)
1553 
begin : WE_
1554 
   if (freq_error==1'b1)
1555 
        $display("WARNING: Frequency should be less than %d MHz for SPI interface. Write Enable is not allowed.",fSCK);
1556 
 
1557 
        @ (posedge CSB);
1558 
        WEL = 1'b1;
1559 
        $display ("Write Enable Latch Set");
1560 
end
1561 
 
1562 
// ************ Write Disable ******************** //
1563 
always @(WD)
1564 
begin : WD_
1565 
   if (freq_error==1'b1)
1566 
        $display("WARNING: Frequency should be less than %d MHz for SPI interface. Write Disable is not allowed.",fSCK);
1567 
 
1568 
        @ (posedge CSB);
1569 
        WEL = 1'b0;
1570 
        seq_byte_start = 1'b0;
1571 
        SPM = 1'b0;
1572 
        $display ("Write Enable Latch Reset");
1573 
end
1574 
 
1575 
// ******************** Read Array ********************** //
1576 
always @(RA)
1577 
begin : RA_
1578 
        if (RDYnBSY == 1'b1) // device is already busy
1579 
        begin
1580 
                $display ("Device %s is busy. Read Array is not allowed", DEVICE);
1581 
                disable RA_;
1582 
        end
1583 
        // if it comes here, means, the above if was false.
1584 
 
1585 
   if (freq_error==1'b1)
1586 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Read Array is not allowed",fSCK);
1587 
 
1588 
        get_data;
1589 
        temp_addr [23:16] = read_data [7:0];
1590 
        get_data;
1591 
        temp_addr [15:8] = read_data [7:0];
1592 
        get_data;
1593 
        temp_addr [7:0] = read_data [7:0];
1594 
        current_address = temp_addr;
1595 
 
1596 
        if(rd_dummy==1'b1 && CSB==1'b0) // for SCK freq, receive 8 dummy bits
1597 
        begin
1598 
                for (dummy = 7; dummy >= 0; dummy = dummy - 1) // these are dont-care, so discarded
1599 
                begin
1600 
                        @(posedge SCK);
1601 
                        read_dummy[dummy] = SI;
1602 
                        if(HOLDB==1'b0)
1603 
                                wait (HOLDB);
1604 
                end
1605 
                read_dummy = 8'b0;
1606 
        end
1607 
 
1608 
        read_out_array(current_address); // read continuously from memory untill CSB deasserted
1609 
        current_address = 24'b0;
1610 
end
1611 
 
1612 
// ****************** Protect Sector ****************** //
1613 
always @(PS)
1614 
begin : PS_
1615 
        if (RDYnBSY == 1'b1) // device is already busy
1616 
        begin
1617 
                $display ("Device %s is busy. Protect Sector is not allowed", DEVICE);
1618 
                disable PS_ ;
1619 
        end
1620 
        // if it comes here, means, the above if was false.
1621 
 
1622 
   if (freq_error==1'b1)
1623 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Protect Sector is not allowed",fSCK);
1624 
 
1625 
        get_data;
1626 
        temp_addr [23:16] = read_data [7:0];
1627 
        get_data;
1628 
        temp_addr [15:8] = read_data [7:0];
1629 
        get_data;
1630 
        temp_addr [7:0] = read_data [7:0];
1631 
        current_address = temp_addr;
1632 
 
1633 
        @ (posedge CSB);
1634 
        if(WEL==1'b1 && SPRL==1'b0)
1635 
        begin
1636 
                RDYnBSY = 1'b1;
1637 
                protect = 1'b1;
1638 
                protect_sector(current_address);
1639 
                #tSECP;
1640 
                $display ("Sector for Address %h is Protected", current_address);
1641 
        end
1642 
        else
1643 
                $display ("WEL bit not set or Sector Protection Register Locked. Protect Sector is not allowed");
1644 
        WEL = 1'b0;
1645 
        RDYnBSY = 1'b0;
1646 
        protect = 1'b0;
1647 
        current_address = 24'b0;
1648 
end
1649 
 
1650 
// ****************** Un-Protect Sector ****************** //
1651 
always @(UPS)
1652 
begin : UPS_
1653 
        if (RDYnBSY == 1'b1) // device is already busy
1654 
        begin
1655 
                $display ("Device %s is busy. Un-Protect Sector is not allowed", DEVICE);
1656 
                disable UPS_ ;
1657 
        end
1658 
        // if it comes here, means, the above if was false.
1659 
 
1660 
   if (freq_error==1'b1)
1661 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Un-Protect Sector is not allowed",fSCK);
1662 
 
1663 
        get_data;
1664 
        temp_addr [23:16] = read_data [7:0];
1665 
        get_data;
1666 
        temp_addr [15:8] = read_data [7:0];
1667 
        get_data;
1668 
        temp_addr [7:0] = read_data [7:0];
1669 
        current_address = temp_addr;
1670 
 
1671 
        @ (posedge CSB);
1672 
        if(WEL==1'b1 && SPRL==1'b0)
1673 
        begin
1674 
                RDYnBSY = 1'b1;
1675 
                unprotect = 1'b1;
1676 
                unprotect_sector(current_address);
1677 
                #tSECUP;
1678 
                $display ("Sector for Address %h is UnProtected", current_address);
1679 
        end
1680 
        else
1681 
                $display ("WEL bit not set or Sector Protection Register Locked. Un-Protect Sector is not allowed");
1682 
 
1683 
        unprotect = 1'b0;
1684 
        WEL = 1'b0;
1685 
        RDYnBSY = 1'b0;
1686 
        current_address = 24'b0;
1687 
end
1688 
 
1689 
// ****************** Read Sector Protection Register ****************** //
1690 
always @(RSPR)
1691 
begin : RSPR_
1692 
        if (RDYnBSY == 1'b1) // device is already busy
1693 
        begin
1694 
                $display ("Device %s is busy. Read Sector Protection Register is not allowed", DEVICE);
1695 
                disable RSPR_ ;
1696 
        end
1697 
        // if it comes here, means, the above if was false.
1698 
 
1699 
   if (freq_error==1'b1)
1700 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Read Sector Protection Register is not allowed",fSCK);
1701 
 
1702 
        get_data;
1703 
        temp_addr [23:16] = read_data [7:0];
1704 
        get_data;
1705 
        temp_addr [15:8] = read_data [7:0];
1706 
        get_data;
1707 
        temp_addr [7:0] = read_data [7:0];
1708 
        current_address = temp_addr;
1709 
 
1710 
        check_protection(current_address);
1711 
        if(protected==1'b1)
1712 
                $display ("Sector for Address %h is Protected", current_address);
1713 
        else
1714 
                $display ("Sector for Address %h is UnProtected", current_address);
1715 
 
1716 
        send_protection_status; // sending the Sector Protection Register content in SO
1717 
        current_address = 24'b0;
1718 
        $display ("Read Sector Protection Register completed");
1719 
end
1720 
 
1721 
// ********************* Byte Program ********************* //
1722 
always @(BP)
1723 
begin : BP_
1724 
        if (RDYnBSY == 1'b1) // device is already busy
1725 
        begin
1726 
                $display ("Device %s is busy. Byte Program is not allowed", DEVICE);
1727 
                disable BP_ ;
1728 
        end
1729 
        // if it comes here, means, the above if was false.
1730 
 
1731 
   if (freq_error==1'b1)
1732 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Byte Program is not allowed",fSCK);
1733 
 
1734 
        // to receive 3 bytes of address
1735 
        get_data;
1736 
        temp_addr [23:16] = read_data [7:0];
1737 
        get_data;
1738 
        temp_addr [15:8] = read_data [7:0];
1739 
        get_data;
1740 
        temp_addr [7:0] = read_data [7:0];
1741 
        current_address = temp_addr;
1742 
 
1743 
/*
1744 
        // to receive 1 bytes of data
1745 
        get_data;
1746 
        data_in [7:0] = read_data [7:0];
1747 
*/
1748 
        page_program;   // page program - receives data
1749 
 
1750 
        if(pp_i < 8)    // page program should not proceed if CSB deasserted at intermediate points
1751 
        begin
1752 
                $display ("Chip Select deasserted in non-even point. Byte/Page Program is not allowed");
1753 
                WEL = 1'b0;
1754 
                EPE = 1'b1;
1755 
                disable BP_ ;
1756 
        end
1757 
 
1758 
        if(WEL==1'b0)
1759 
        begin
1760 
                $display ("WEL bit not set. Byte Program is not allowed");
1761 
                disable BP_ ;
1762 
        end
1763 
 
1764 
        check_protection(current_address);
1765 
 
1766 
        if(protected==1'b1)
1767 
        begin
1768 
                $display("Sector for Address %h is Protected. Byte Program cannot be performed", current_address);
1769 
                WEL = 1'b0;
1770 
                disable BP_ ;
1771 
        end
1772 
        else
1773 
        begin
1774 
                $display ("Sector for Address %h is UnProtected, Byte Program can be performed", current_address);
1775 
//              @ (posedge CSB);
1776 
                RDYnBSY = 1'b1;
1777 
                byte_prog = 1'b1;
1778 
                pp_address = current_address[7:0];
1779 
 
1780 
                for(pp = 0; pp < pp_j; pp = pp+1)
1781 
                begin
1782 
                        data_in = int_buffer[pp];
1783 
                        byte_program({current_address[23:8],pp_address}, data_in);
1784 
                        pp_address = pp_address + 1'b1;
1785 
                end
1786 
                $display("Byte write completed");
1787 
 
1788 
                #tPP;
1789 
                pp               = 0;
1790 
                pp_j             = 0;
1791 
                pp_i             = 0;
1792 
                WEL              = 1'b0;
1793 
                RDYnBSY          = 1'b0;
1794 
                byte_prog        = 1'b0;
1795 
                current_address  = 24'b0;
1796 
                pp_address       = 8'b0;
1797 
                data_in          = 8'b0;
1798 
        end
1799 
end
1800 
 
1801 
// ********************* Sequential Byte Program ********************* //
1802 
always @(SBP)
1803 
begin : SBP_
1804 
        if (RDYnBSY == 1'b1) // device is already busy
1805 
        begin
1806 
                $display ("Device %s is busy. Sequential Byte Program is not allowed", DEVICE);
1807 
                disable SBP_ ;
1808 
        end
1809 
        // if it comes here, means, the above if was false.
1810 
 
1811 
   if (freq_error==1'b1)
1812 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Sequential Byte Program is not allowed",fSCK);
1813 
 
1814 
        if(seq_byte_start==1'b0)
1815 
        begin
1816 
        // to receive 3 bytes of address
1817 
                get_data;
1818 
                temp_addr [23:16] = read_data [7:0];
1819 
                get_data;
1820 
                temp_addr [15:8] = read_data [7:0];
1821 
                get_data;
1822 
                temp_addr [7:0] = read_data [7:0];
1823 
                current_address = temp_addr;
1824 
        end
1825 
 
1826 
        SPM = 1'b1;     // Entered Sequential Byte Programing mode
1827 
 
1828 
        if(seq_byte_start==1'b1)        // to increment address when entering sequential mode
1829 
        begin
1830 
                if(current_address < (MEMSIZE-1))
1831 
                        current_address = current_address + 1'b1;
1832 
                else if(current_address == (MEMSIZE-1))
1833 
                begin
1834 
                        $display ("Sequential Byte Program for device: %s reaches end of memory (%h). No Wrapping allowed. Sequential Byte Program is not allowed", DEVICE, MEMSIZE-1);
1835 
                        WEL = 1'b0;
1836 
                        SPM = 1'b0;
1837 
                        seq_byte_start = 1'b0;
1838 
                        disable SBP_ ;
1839 
                end
1840 
        end
1841 
 
1842 
        // to receive 1 bytes of data
1843 
        get_data;
1844 
        data_in [7:0] = read_data [7:0];
1845 
 
1846 
        if(WEL==1'b0)
1847 
        begin
1848 
                $display ("WEL bit not set. Sequential Byte Program is not allowed");
1849 
                seq_byte_start = 1'b0;
1850 
                SPM = 1'b0;
1851 
                disable SBP_ ;
1852 
        end
1853 
 
1854 
        check_protection(current_address);
1855 
 
1856 
        if(protected==1'b1)
1857 
        begin
1858 
                $display("Sector for Address %h is Protected. Sequential Byte Program cannot be performed", current_address);
1859 
                seq_byte_start = 1'b0;
1860 
                WEL = 1'b0;
1861 
                SPM = 1'b0;
1862 
                disable SBP_ ;
1863 
        end
1864 
        else
1865 
        begin
1866 
                $display ("Sector for Address %h is UnProtected, Sequential Byte Program can be performed", current_address);
1867 
                @ (posedge CSB);
1868 
                RDYnBSY = 1'b1;
1869 
                seq_byte_prog = 1'b1;
1870 
 
1871 
                byte_program(current_address, data_in);
1872 
                $display("Sequential Byte write completed");
1873 
 
1874 
                #tBP;
1875 
                RDYnBSY = 1'b0;
1876 
                seq_byte_prog = 1'b0;
1877 
                data_in = 8'b0;
1878 
                seq_byte_start = 1'b1;
1879 
        end
1880 
end
1881 
 
1882 
// ********************* 4kB Block Erase ********************* //
1883 
always @(BE4)
1884 
begin : BE4_
1885 
        if (RDYnBSY == 1'b1) // device is already busy
1886 
        begin
1887 
                $display ("Device %s is busy. 4KB Block Erase is not allowed", DEVICE);
1888 
                disable BE4_ ;
1889 
        end
1890 
        // if it comes here, means, the above if was false.
1891 
 
1892 
   if (freq_error==1'b1)
1893 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. 4KB Block Erase is not allowed",fSCK);
1894 
 
1895 
        get_data;
1896 
        temp_addr [23:16] = read_data [7:0];
1897 
        get_data;
1898 
        temp_addr [15:8] = read_data [7:0];
1899 
        get_data;
1900 
        temp_addr [7:0] = read_data [7:0];
1901 
        current_address = temp_addr;
1902 
 
1903 
        if(WEL==1'b0)
1904 
        begin
1905 
                $display ("WEL bit not set. 4KB Block Erase is not allowed");
1906 
                disable BE4_ ;
1907 
        end
1908 
 
1909 
        check_protection(current_address);
1910 
 
1911 
        if(protected==1'b1)
1912 
        begin
1913 
                $display("Sector for Address %h is Protected. 4KB Block Erase cannot be performed", current_address);
1914 
                WEL = 1'b0;
1915 
                disable BE4_ ;
1916 
        end
1917 
        else
1918 
        begin
1919 
                $display ("Sector for Address %h is UnProtected, 4KB Block Erase can be performed", current_address);
1920 
                @ (posedge CSB);
1921 
                RDYnBSY = 1'b1;
1922 
                erasing_block4 = 1'b1;
1923 
 
1924 
                erase_4kb(current_address);
1925 
                #tBLKE4;
1926 
 
1927 
                $display ("4kB Block with start address %h erased", {current_address[23:12],12'b0});
1928 
                WEL = 1'b0;
1929 
                RDYnBSY = 1'b0;
1930 
                current_address = 24'b0;
1931 
                erasing_block4 = 1'b0;
1932 
        end
1933 
end
1934 
 
1935 
// ********************* 32kB Block Erase ********************* //
1936 
always @(BE32)
1937 
begin : BE32_
1938 
        if (RDYnBSY == 1'b1) // device is already busy
1939 
        begin
1940 
                $display ("Device %s is busy. 32KB Block Erase is not allowed", DEVICE);
1941 
                disable BE32_ ;
1942 
        end
1943 
        // if it comes here, means, the above if was false.
1944 
 
1945 
   if (freq_error==1'b1)
1946 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. 32KB Block Erase is not allowed",fSCK);
1947 
 
1948 
        get_data;
1949 
        temp_addr [23:16] = read_data [7:0];
1950 
        get_data;
1951 
        temp_addr [15:8] = read_data [7:0];
1952 
        get_data;
1953 
        temp_addr [7:0] = read_data [7:0];
1954 
        current_address = temp_addr;
1955 
 
1956 
        if(WEL==1'b0)
1957 
        begin
1958 
                $display ("WEL bit not set. 32KB Block Erase is not allowed");
1959 
                disable BE32_ ;
1960 
        end
1961 
 
1962 
        if(DEVICE == "AT25DF041A" && current_address[23:15]==9'b0000_0111_1)
1963 
        begin
1964 
                check_protection({current_address[23:16],2'b11,14'b0});
1965 
                if(protected==1'b1)
1966 
                begin
1967 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],2'b11,14'b0});
1968 
                        EPE = 1'b1;
1969 
                        WEL = 1'b0;
1970 
                        disable BE32_ ;
1971 
                end
1972 
                check_protection({current_address[23:16],3'b100,13'b0});
1973 
                if(protected==1'b1)
1974 
                begin
1975 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],3'b100,13'b0});
1976 
                        EPE = 1'b1;
1977 
                        WEL = 1'b0;
1978 
                        disable BE32_ ;
1979 
                end
1980 
                check_protection({current_address[23:16],3'b101,13'b0});
1981 
                if(protected==1'b1)
1982 
                begin
1983 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],3'b101,13'b0});
1984 
                        EPE = 1'b1;
1985 
                        WEL = 1'b0;
1986 
                        disable BE32_ ;
1987 
                end
1988 
        end
1989 
        else if(DEVICE == "AT26DF081A" && current_address[23:15]==9'b0000_1111_0)
1990 
        begin
1991 
                check_protection({current_address[23:16],2'b00,15'b0});
1992 
                if(protected==1'b1)
1993 
                begin
1994 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],2'b00,15'b0});
1995 
                        EPE = 1'b1;
1996 
                        WEL = 1'b0;
1997 
                        disable BE32_ ;
1998 
                end
1999 
                check_protection({current_address[23:16],3'b010,13'b0});
2000 
                if(protected==1'b1)
2001 
                begin
2002 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],3'b010,13'b0});
2003 
                        EPE = 1'b1;
2004 
                        WEL = 1'b0;
2005 
                        disable BE32_ ;
2006 
                end
2007 
                check_protection({current_address[23:16],3'b011,13'b0});
2008 
                if(protected==1'b1)
2009 
                begin
2010 
                        $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", {current_address[23:16],3'b011,13'b0});
2011 
                        EPE = 1'b1;
2012 
                        WEL = 1'b0;
2013 
                        disable BE32_ ;
2014 
                end
2015 
        end
2016 
        else
2017 
                check_protection(current_address);
2018 
 
2019 
        if(protected==1'b1)
2020 
        begin
2021 
                $display("Sector for Address %h is Protected. 32KB Block Erase cannot be performed", current_address);
2022 
                WEL = 1'b0;
2023 
                disable BE32_ ;
2024 
        end
2025 
        else
2026 
        begin
2027 
                $display ("Sector for Address %h is UnProtected, 32KB Block Erase can be performed", current_address);
2028 
                @ (posedge CSB);
2029 
                RDYnBSY = 1'b1;
2030 
                erasing_block32 = 1'b1;
2031 
 
2032 
                erase_32kb(current_address);
2033 
                #tBLKE32;
2034 
 
2035 
                $display ("32KB Block with start address %h erased", {current_address[23:15],15'b0});
2036 
                WEL = 1'b0;
2037 
                RDYnBSY = 1'b0;
2038 
                current_address = 24'b0;
2039 
                erasing_block32 = 1'b0;
2040 
        end
2041 
end
2042 
 
2043 
// ********************* 64kB Block Erase ********************* //
2044 
always @(BE64)
2045 
begin : BE64_
2046 
        if (RDYnBSY == 1'b1) // device is already busy
2047 
        begin
2048 
                $display ("Device %s is busy. 64KB Block Erase is not allowed", DEVICE);
2049 
                disable BE64_ ;
2050 
        end
2051 
        // if it comes here, means, the above if was false.
2052 
 
2053 
   if (freq_error==1'b1)
2054 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. 64KB Block Erase is not allowed",fSCK);
2055 
 
2056 
        get_data;
2057 
        temp_addr [23:16] = read_data [7:0];
2058 
        get_data;
2059 
        temp_addr [15:8] = read_data [7:0];
2060 
        get_data;
2061 
        temp_addr [7:0] = read_data [7:0];
2062 
        current_address = temp_addr;
2063 
 
2064 
        if(WEL==1'b0)
2065 
        begin
2066 
                $display ("WEL bit not set. 64KB Block Erase is not allowed");
2067 
                disable BE64_ ;
2068 
        end
2069 
 
2070 
        if(DEVICE == "AT25DF041A" && current_address[23:16]==8'b0000_0111)
2071 
        begin
2072 
                check_protection({current_address[23:16],1'b0,15'b0});
2073 
                if(protected==1'b1)
2074 
                begin
2075 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],1'b0,15'b0});
2076 
                        EPE = 1'b1;
2077 
                        WEL = 1'b0;
2078 
                        disable BE64_ ;
2079 
                end
2080 
                check_protection({current_address[23:16],2'b11,14'b0});
2081 
                if(protected==1'b1)
2082 
                begin
2083 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],2'b11,14'b0});
2084 
                        EPE = 1'b1;
2085 
                        WEL = 1'b0;
2086 
                        disable BE64_ ;
2087 
                end
2088 
                check_protection({current_address[23:16],3'b100,13'b0});
2089 
                if(protected==1'b1)
2090 
                begin
2091 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],3'b100,13'b0});
2092 
                        EPE = 1'b1;
2093 
                        WEL = 1'b0;
2094 
                        disable BE64_ ;
2095 
                end
2096 
                check_protection({current_address[23:16],3'b101,13'b0});
2097 
                if(protected==1'b1)
2098 
                begin
2099 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],3'b101,13'b0});
2100 
                        EPE = 1'b1;
2101 
                        WEL = 1'b0;
2102 
                        disable BE64_ ;
2103 
                end
2104 
        end
2105 
        else if(DEVICE == "AT26DF081A" && current_address[23:16]==8'b0000_1111)
2106 
        begin
2107 
                check_protection({current_address[23:16],2'b00,15'b0});
2108 
                if(protected==1'b1)
2109 
                begin
2110 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],2'b00,15'b0});
2111 
                        EPE = 1'b1;
2112 
                        WEL = 1'b0;
2113 
                        disable BE64_ ;
2114 
                end
2115 
                check_protection({current_address[23:16],1'b1,14'b0});
2116 
                if(protected==1'b1)
2117 
                begin
2118 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],1'b1,14'b0});
2119 
                        EPE = 1'b1;
2120 
                        WEL = 1'b0;
2121 
                        disable BE64_ ;
2122 
                end
2123 
                check_protection({current_address[23:16],3'b010,13'b0});
2124 
                if(protected==1'b1)
2125 
                begin
2126 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],3'b010,13'b0});
2127 
                        EPE = 1'b1;
2128 
                        WEL = 1'b0;
2129 
                        disable BE64_ ;
2130 
                end
2131 
                check_protection({current_address[23:16],3'b011,13'b0});
2132 
                if(protected==1'b1)
2133 
                begin
2134 
                        $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", {current_address[23:16],3'b011,13'b0});
2135 
                        EPE = 1'b1;
2136 
                        WEL = 1'b0;
2137 
                        disable BE64_ ;
2138 
                end
2139 
        end
2140 
        else
2141 
                check_protection(current_address);
2142 
 
2143 
        if(protected==1'b1)
2144 
        begin
2145 
                $display("Sector for Address %h is Protected. 64KB Block Erase cannot be performed", current_address);
2146 
                WEL = 1'b0;
2147 
                disable BE64_ ;
2148 
        end
2149 
        else
2150 
        begin
2151 
                $display ("Sector for Address %h is UnProtected, 64KB Block Erase can be performed", current_address);
2152 
                @ (posedge CSB);
2153 
                RDYnBSY = 1'b1;
2154 
                erasing_block64 = 1'b1;
2155 
 
2156 
                erase_64kb(current_address);
2157 
                #tBLKE64;
2158 
 
2159 
                $display ("64kB Block with start address %h erased", {current_address[23:16],16'b0});
2160 
                WEL = 1'b0;
2161 
                RDYnBSY = 1'b0;
2162 
                current_address = 24'b0;
2163 
                erasing_block64 = 1'b0;
2164 
        end
2165 
end
2166 
 
2167 
// ********************* Chip Erase ********************* //
2168 
always @(CE)
2169 
begin : CE_
2170 
        if (RDYnBSY == 1'b1) // device is already busy
2171 
        begin
2172 
                $display ("Device %s is busy. Chip Erase is not allowed", DEVICE);
2173 
                disable CE_ ;
2174 
        end
2175 
        // if it comes here, means, the above if was false.
2176 
 
2177 
   if (freq_error==1'b1)
2178 
        $display ("WARNING: Frequency should be less than %d MHz for SPI interface. Chip Erase is not allowed",fSCK);
2179 
 
2180 
        if(WEL==1'b0)
2181 
        begin
2182 
                $display ("WEL bit not set. Chip Erase is not allowed");
2183 
                disable CE_ ;
2184 
        end
2185 
 
2186 
        if(SWP==2'b00)
2187 
        begin
2188 
                $display("All Sectors in the chip are UnProtected. Chip Erase can be performed");
2189 
                @ (posedge CSB);
2190 
                RDYnBSY = 1'b1;
2191 
                erasing_chip = 1'b1;
2192 
 
2193 
                erase_chip;
2194 
                for(delay =0; delay < tmult; delay = delay+1)
2195 
                        #tCHPEn;
2196 
 
2197 
                WEL = 1'b0;
2198 
                RDYnBSY = 1'b0;
2199 
                erasing_chip = 1'b0;
2200 
        end
2201 
        else if(SWP!=2'b00)
2202 
        begin
2203 
                $display("Some or all Sectors in the chip is Protected. Chip Erase cannot be performed");
2204 
                EPE = 1'b1;
2205 
                disable CE_ ;
2206 
        end
2207 
 
2208 
        $display ("Chip Erase Completed");
2209 
end
2210 
 
2211 
// ******** Posedge CSB. Stop all reading, recvng. commands/addresses etc. ********* //
2212 
 
2213 
always @(posedge CSB)
2214 
begin
2215 
        disable RA_;    // Read Array (low freq and normal freq)
2216 
        disable MIR_;   // MIR will stop, if CSB goes high
2217 
        disable RSR_;   // Status reading should stop.
2218 
 
2219 
        disable get_opcode;             // Stop opcode retrieval
2220 
        disable get_data;               // Stop address/data retrieval
2221 
        disable read_out_array;         // send data in SO
2222 
        disable send_protection_status; // Send Protection status
2223 
        disable page_program;
2224 
 
2225 
        temp_data = 8'b0;
2226 
        temp_addr = 24'b0;
2227 
        rd_dummy = 1'b0;
2228 
        status_read = 1'b0;
2229 
        protected = 1'b0;
2230 
        read_data = 8'b0;
2231 
        EPE = 1'b0;
2232 
 
2233 
        #tDIS SO_on = 1'b0;  // SO is now in high-impedance
2234 
        SO_reg = 1'b0;
2235 
end
2236 
 
2237 
// ********************** Frequeny Checking ********************** //
2238 
always @ (negedge SCK)
2239 
begin
2240 
        tperiod <= $time;
2241 
        tperiod1 <= tperiod;
2242 
end
2243 
 
2244 22 julius 
//always @(tperiod or tperiod1)
2245 
always @(negedge SCK)
2246 15 unneback 
begin
2247 
        if ((tperiod - tperiod1) < (tSCKH + tSCKH))
2248 
        begin
2249 22 julius 
                //freq_error = 1'b1;
2250 
                //$display("Frequency exceeds max limit (14285 ms). Time period detected is %t", (tperiod -tperiod1));
2251 15 unneback 
        end
2252 
        else
2253 
                freq_error = 1'b0;
2254 
 
2255 
end // always
2256 
// **************************************************************** //
2257 
 
2258 
endmodule

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