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[/] [i2cslave/] [trunk/] [model/] [i2c_master_top.v] - Blame information for rev 5

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/////////////////////////////////////////////////////////////////////
////                                                             ////
////  WISHBONE revB.2 compliant I2C Master controller Top-level  ////
////                                                             ////
////                                                             ////
////  Author: Richard Herveille                                  ////
////          richard@asics.ws                                   ////
////          www.asics.ws                                       ////
////                                                             ////
////  Downloaded from: http://www.opencores.org/projects/i2c/    ////
////                                                             ////
/////////////////////////////////////////////////////////////////////
////                                                             ////
//// Copyright (C) 2001 Richard Herveille                        ////
////                    richard@asics.ws                         ////
////                                                             ////
//// This source file may be used and distributed without        ////
//// restriction provided that this copyright statement is not   ////
//// removed from the file and that any derivative work contains ////
//// the original copyright notice and the associated disclaimer.////
////                                                             ////
////     THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY     ////
//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED   ////
//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS   ////
//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR      ////
//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,         ////
//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    ////
//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE   ////
//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR        ////
//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF  ////
//// LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT  ////
//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT  ////
//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE         ////
//// POSSIBILITY OF SUCH DAMAGE.                                 ////
////                                                             ////
/////////////////////////////////////////////////////////////////////
 
//  CVS Log
//
//  $Id: i2c_master_top.v,v 1.1 2008-11-08 13:15:10 sfielding Exp $
//
//  $Date: 2008-11-08 13:15:10 $
//  $Revision: 1.1 $
//  $Author: sfielding $
//  $Locker:  $
//  $State: Exp $
//
// Change History:
//               $Log: not supported by cvs2svn $
//               Revision 1.11  2005/02/27 09:26:24  rherveille
//               Fixed register overwrite issue.
//               Removed full_case pragma, replaced it by a default statement.
//
//               Revision 1.10  2003/09/01 10:34:38  rherveille
//               Fix a blocking vs. non-blocking error in the wb_dat output mux.
//
//               Revision 1.9  2003/01/09 16:44:45  rherveille
//               Fixed a bug in the Command Register declaration.
//
//               Revision 1.8  2002/12/26 16:05:12  rherveille
//               Small code simplifications
//
//               Revision 1.7  2002/12/26 15:02:32  rherveille
//               Core is now a Multimaster I2C controller
//
//               Revision 1.6  2002/11/30 22:24:40  rherveille
//               Cleaned up code
//
//               Revision 1.5  2001/11/10 10:52:55  rherveille
//               Changed PRER reset value from 0x0000 to 0xffff, conform specs.
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
 
`include "i2c_master_defines.v"
 
module i2c_master_top(
        wb_clk_i, wb_rst_i, arst_i, wb_adr_i, wb_dat_i, wb_dat_o,
        wb_we_i, wb_stb_i, wb_cyc_i, wb_ack_o, wb_inta_o,
        scl_pad_i, scl_pad_o, scl_padoen_o, sda_pad_i, sda_pad_o, sda_padoen_o );
 
        // parameters
        parameter ARST_LVL = 1'b0; // asynchronous reset level
 
        //
        // inputs & outputs
        //
 
        // wishbone signals
        input        wb_clk_i;     // master clock input
        input        wb_rst_i;     // synchronous active high reset
        input        arst_i;       // asynchronous reset
        input  [2:0] wb_adr_i;     // lower address bits
        input  [7:0] wb_dat_i;     // databus input
        output [7:0] wb_dat_o;     // databus output
        input        wb_we_i;      // write enable input
        input        wb_stb_i;     // stobe/core select signal
        input        wb_cyc_i;     // valid bus cycle input
        output       wb_ack_o;     // bus cycle acknowledge output
        output       wb_inta_o;    // interrupt request signal output
 
        reg [7:0] wb_dat_o;
        reg wb_ack_o;
        reg wb_inta_o;
 
        // I2C signals
        // i2c clock line
        input  scl_pad_i;       // SCL-line input
        output scl_pad_o;       // SCL-line output (always 1'b0)
        output scl_padoen_o;    // SCL-line output enable (active low)
 
        // i2c data line
        input  sda_pad_i;       // SDA-line input
        output sda_pad_o;       // SDA-line output (always 1'b0)
        output sda_padoen_o;    // SDA-line output enable (active low)
 
 
        //
        // variable declarations
        //
 
        // registers
        reg  [15:0] prer; // clock prescale register
        reg  [ 7:0] ctr;  // control register
        reg  [ 7:0] txr;  // transmit register
        wire [ 7:0] rxr;  // receive register
        reg  [ 7:0] cr;   // command register
        wire [ 7:0] sr;   // status register
 
        // done signal: command completed, clear command register
        wire done;
 
        // core enable signal
        wire core_en;
        wire ien;
 
        // status register signals
        wire irxack;
        reg  rxack;       // received aknowledge from slave
        reg  tip;         // transfer in progress
        reg  irq_flag;    // interrupt pending flag
        wire i2c_busy;    // bus busy (start signal detected)
        wire i2c_al;      // i2c bus arbitration lost
        reg  al;          // status register arbitration lost bit
 
        //
        // module body
        //
 
        // generate internal reset
        wire rst_i = arst_i ^ ARST_LVL;
 
        // generate wishbone signals
        wire wb_wacc = wb_cyc_i & wb_stb_i & wb_we_i;
 
        // generate acknowledge output signal
        always @(posedge wb_clk_i)
          wb_ack_o <= #1 wb_cyc_i & wb_stb_i & ~wb_ack_o; // because timing is always honored
 
        // assign DAT_O
        always @(posedge wb_clk_i)
        begin
          case (wb_adr_i) // synopsis parallel_case
            3'b000: wb_dat_o <= #1 prer[ 7:0];
            3'b001: wb_dat_o <= #1 prer[15:8];
            3'b010: wb_dat_o <= #1 ctr;
            3'b011: wb_dat_o <= #1 rxr; // write is transmit register (txr)
            3'b100: wb_dat_o <= #1 sr;  // write is command register (cr)
            3'b101: wb_dat_o <= #1 txr;
            3'b110: wb_dat_o <= #1 cr;
            3'b111: wb_dat_o <= #1 0;   // reserved
          endcase
        end
 
        // generate registers
        always @(posedge wb_clk_i or negedge rst_i)
          if (!rst_i)
            begin
                prer <= #1 16'hffff;
                ctr  <= #1  8'h0;
                txr  <= #1  8'h0;
            end
          else if (wb_rst_i)
            begin
                prer <= #1 16'hffff;
                ctr  <= #1  8'h0;
                txr  <= #1  8'h0;
            end
          else
            if (wb_wacc)
              case (wb_adr_i) // synopsis parallel_case
                 3'b000 : prer [ 7:0] <= #1 wb_dat_i;
                 3'b001 : prer [15:8] <= #1 wb_dat_i;
                 3'b010 : ctr         <= #1 wb_dat_i;
                 3'b011 : txr         <= #1 wb_dat_i;
                 default: ;
              endcase
 
        // generate command register (special case)
        always @(posedge wb_clk_i or negedge rst_i)
          if (~rst_i)
            cr <= #1 8'h0;
          else if (wb_rst_i)
            cr <= #1 8'h0;
          else if (wb_wacc)
            begin
                if (core_en & (wb_adr_i == 3'b100) )
                  cr <= #1 wb_dat_i;
            end
          else
            begin
                if (done | i2c_al)
                  cr[7:4] <= #1 4'h0;           // clear command bits when done
                                                // or when aribitration lost
                cr[2:1] <= #1 2'b0;             // reserved bits
                cr[0]   <= #1 2'b0;             // clear IRQ_ACK bit
            end
 
 
        // decode command register
        wire sta  = cr[7];
        wire sto  = cr[6];
        wire rd   = cr[5];
        wire wr   = cr[4];
        wire ack  = cr[3];
        wire iack = cr[0];
 
        // decode control register
        assign core_en = ctr[7];
        assign ien = ctr[6];
 
        // hookup byte controller block
        i2c_master_byte_ctrl byte_controller (
                .clk      ( wb_clk_i     ),
                .rst      ( wb_rst_i     ),
                .nReset   ( rst_i        ),
                .ena      ( core_en      ),
                .clk_cnt  ( prer         ),
                .start    ( sta          ),
                .stop     ( sto          ),
                .read     ( rd           ),
                .write    ( wr           ),
                .ack_in   ( ack          ),
                .din      ( txr          ),
                .cmd_ack  ( done         ),
                .ack_out  ( irxack       ),
                .dout     ( rxr          ),
                .i2c_busy ( i2c_busy     ),
                .i2c_al   ( i2c_al       ),
                .scl_i    ( scl_pad_i    ),
                .scl_o    ( scl_pad_o    ),
                .scl_oen  ( scl_padoen_o ),
                .sda_i    ( sda_pad_i    ),
                .sda_o    ( sda_pad_o    ),
                .sda_oen  ( sda_padoen_o )
        );
 
        // status register block + interrupt request signal
        always @(posedge wb_clk_i or negedge rst_i)
          if (!rst_i)
            begin
                al       <= #1 1'b0;
                rxack    <= #1 1'b0;
                tip      <= #1 1'b0;
                irq_flag <= #1 1'b0;
            end
          else if (wb_rst_i)
            begin
                al       <= #1 1'b0;
                rxack    <= #1 1'b0;
                tip      <= #1 1'b0;
                irq_flag <= #1 1'b0;
            end
          else
            begin
                al       <= #1 i2c_al | (al & ~sta);
                rxack    <= #1 irxack;
                tip      <= #1 (rd | wr);
                irq_flag <= #1 (done | i2c_al | irq_flag) & ~iack; // interrupt request flag is always generated
            end
 
        // generate interrupt request signals
        always @(posedge wb_clk_i or negedge rst_i)
          if (!rst_i)
            wb_inta_o <= #1 1'b0;
          else if (wb_rst_i)
            wb_inta_o <= #1 1'b0;
          else
            wb_inta_o <= #1 irq_flag && ien; // interrupt signal is only generated when IEN (interrupt enable bit is set)
 
        // assign status register bits
        assign sr[7]   = rxack;
        assign sr[6]   = i2c_busy;
        assign sr[5]   = al;
        assign sr[4:2] = 3'h0; // reserved
        assign sr[1]   = tip;
        assign sr[0]   = irq_flag;
 
endmodule

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[/] [i2cslave/] [trunk/] [model/] [i2c_master_top.v] - Blame information for rev 5

Line No.	Rev	Author	Line
1	2	sfielding	`/////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// WISHBONE revB.2 compliant I2C Master controller Top-level ////`
4			`//// ////`
5			`//// ////`
6			`//// Author: Richard Herveille ////`
7			`//// richard@asics.ws ////`
8			`//// www.asics.ws ////`
9			`//// ////`
10			`//// Downloaded from: http://www.opencores.org/projects/i2c/ ////`
11			`//// ////`
12			`/////////////////////////////////////////////////////////////////////`
13			`//// ////`
14			`//// Copyright (C) 2001 Richard Herveille ////`
15			`//// richard@asics.ws ////`
16			`//// ////`
17			`//// This source file may be used and distributed without ////`
18			`//// restriction provided that this copyright statement is not ////`
19			`//// removed from the file and that any derivative work contains ////`
20			`//// the original copyright notice and the associated disclaimer.////`
21			`//// ////`
22			//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
23			`//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////`
24			`//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////`
25			`//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////`
26			`//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////`
27			`//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////`
28			`//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////`
29			`//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////`
30			`//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////`
31			`//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////`
32			`//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////`
33			`//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////`
34			`//// POSSIBILITY OF SUCH DAMAGE. ////`
35			`//// ////`
36			`/////////////////////////////////////////////////////////////////////`
37
38			`// CVS Log`
39			`//`
40			`// $Id: i2c_master_top.v,v 1.1 2008-11-08 13:15:10 sfielding Exp $`
41			`//`
42			`// $Date: 2008-11-08 13:15:10 $`
43			`// $Revision: 1.1 $`
44			`// $Author: sfielding $`
45			`// $Locker: $`
46			`// $State: Exp $`
47			`//`
48			`// Change History:`
49			`// $Log: not supported by cvs2svn $`
50			`// Revision 1.11 2005/02/27 09:26:24 rherveille`
51			`// Fixed register overwrite issue.`
52			`// Removed full_case pragma, replaced it by a default statement.`
53			`//`
54			`// Revision 1.10 2003/09/01 10:34:38 rherveille`
55			`// Fix a blocking vs. non-blocking error in the wb_dat output mux.`
56			`//`
57			`// Revision 1.9 2003/01/09 16:44:45 rherveille`
58			`// Fixed a bug in the Command Register declaration.`
59			`//`
60			`// Revision 1.8 2002/12/26 16:05:12 rherveille`
61			`// Small code simplifications`
62			`//`
63			`// Revision 1.7 2002/12/26 15:02:32 rherveille`
64			`// Core is now a Multimaster I2C controller`
65			`//`
66			`// Revision 1.6 2002/11/30 22:24:40 rherveille`
67			`// Cleaned up code`
68			`//`
69			`// Revision 1.5 2001/11/10 10:52:55 rherveille`
70			`// Changed PRER reset value from 0x0000 to 0xffff, conform specs.`
71			`//`
72
73			`// synopsys translate_off`
74			`include "timescale.v"
75			`// synopsys translate_on`
76
77			`include "i2c_master_defines.v"
78
79			`module i2c_master_top(`
80			`wb_clk_i, wb_rst_i, arst_i, wb_adr_i, wb_dat_i, wb_dat_o,`
81			`wb_we_i, wb_stb_i, wb_cyc_i, wb_ack_o, wb_inta_o,`
82			`scl_pad_i, scl_pad_o, scl_padoen_o, sda_pad_i, sda_pad_o, sda_padoen_o );`
83
84			`// parameters`
85			`parameter ARST_LVL = 1'b0; // asynchronous reset level`
86
87			`//`
88			`// inputs & outputs`
89			`//`
90
91			`// wishbone signals`
92			`input wb_clk_i; // master clock input`
93			`input wb_rst_i; // synchronous active high reset`
94			`input arst_i; // asynchronous reset`
95			`input [2:0] wb_adr_i; // lower address bits`
96			`input [7:0] wb_dat_i; // databus input`
97			`output [7:0] wb_dat_o; // databus output`
98			`input wb_we_i; // write enable input`
99			`input wb_stb_i; // stobe/core select signal`
100			`input wb_cyc_i; // valid bus cycle input`
101			`output wb_ack_o; // bus cycle acknowledge output`
102			`output wb_inta_o; // interrupt request signal output`
103
104			`reg [7:0] wb_dat_o;`
105			`reg wb_ack_o;`
106			`reg wb_inta_o;`
107
108			`// I2C signals`
109			`// i2c clock line`
110			`input scl_pad_i; // SCL-line input`
111			`output scl_pad_o; // SCL-line output (always 1'b0)`
112			`output scl_padoen_o; // SCL-line output enable (active low)`
113
114			`// i2c data line`
115			`input sda_pad_i; // SDA-line input`
116			`output sda_pad_o; // SDA-line output (always 1'b0)`
117			`output sda_padoen_o; // SDA-line output enable (active low)`
118
119
120			`//`
121			`// variable declarations`
122			`//`
123
124			`// registers`
125			`reg [15:0] prer; // clock prescale register`
126			`reg [ 7:0] ctr; // control register`
127			`reg [ 7:0] txr; // transmit register`
128			`wire [ 7:0] rxr; // receive register`
129			`reg [ 7:0] cr; // command register`
130			`wire [ 7:0] sr; // status register`
131
132			`// done signal: command completed, clear command register`
133			`wire done;`
134
135			`// core enable signal`
136			`wire core_en;`
137			`wire ien;`
138
139			`// status register signals`
140			`wire irxack;`
141			`reg rxack; // received aknowledge from slave`
142			`reg tip; // transfer in progress`
143			`reg irq_flag; // interrupt pending flag`
144			`wire i2c_busy; // bus busy (start signal detected)`
145			`wire i2c_al; // i2c bus arbitration lost`
146			`reg al; // status register arbitration lost bit`
147
148			`//`
149			`// module body`
150			`//`
151
152			`// generate internal reset`
153			`wire rst_i = arst_i ^ ARST_LVL;`
154
155			`// generate wishbone signals`
156			`wire wb_wacc = wb_cyc_i & wb_stb_i & wb_we_i;`
157
158			`// generate acknowledge output signal`
159			`always @(posedge wb_clk_i)`
160			`wb_ack_o <= #1 wb_cyc_i & wb_stb_i & ~wb_ack_o; // because timing is always honored`
161
162			`// assign DAT_O`
163			`always @(posedge wb_clk_i)`
164			`begin`
165			`case (wb_adr_i) // synopsis parallel_case`
166			`3'b000: wb_dat_o <= #1 prer[ 7:0];`
167			`3'b001: wb_dat_o <= #1 prer[15:8];`
168			`3'b010: wb_dat_o <= #1 ctr;`
169			`3'b011: wb_dat_o <= #1 rxr; // write is transmit register (txr)`
170			`3'b100: wb_dat_o <= #1 sr; // write is command register (cr)`
171			`3'b101: wb_dat_o <= #1 txr;`
172			`3'b110: wb_dat_o <= #1 cr;`
173			`3'b111: wb_dat_o <= #1 0; // reserved`
174			`endcase`
175			`end`
176
177			`// generate registers`
178			`always @(posedge wb_clk_i or negedge rst_i)`
179			`if (!rst_i)`
180			`begin`
181			`prer <= #1 16'hffff;`
182			`ctr <= #1 8'h0;`
183			`txr <= #1 8'h0;`
184			`end`
185			`else if (wb_rst_i)`
186			`begin`
187			`prer <= #1 16'hffff;`
188			`ctr <= #1 8'h0;`
189			`txr <= #1 8'h0;`
190			`end`
191			`else`
192			`if (wb_wacc)`
193			`case (wb_adr_i) // synopsis parallel_case`
194			`3'b000 : prer [ 7:0] <= #1 wb_dat_i;`
195			`3'b001 : prer [15:8] <= #1 wb_dat_i;`
196			`3'b010 : ctr <= #1 wb_dat_i;`
197			`3'b011 : txr <= #1 wb_dat_i;`
198			`default: ;`
199			`endcase`
200
201			`// generate command register (special case)`
202			`always @(posedge wb_clk_i or negedge rst_i)`
203			`if (~rst_i)`
204			`cr <= #1 8'h0;`
205			`else if (wb_rst_i)`
206			`cr <= #1 8'h0;`
207			`else if (wb_wacc)`
208			`begin`
209			`if (core_en & (wb_adr_i == 3'b100) )`
210			`cr <= #1 wb_dat_i;`
211			`end`
212			`else`
213			`begin`
214			`if (done \| i2c_al)`
215			`cr[7:4] <= #1 4'h0; // clear command bits when done`
216			`// or when aribitration lost`
217			`cr[2:1] <= #1 2'b0; // reserved bits`
218			`cr[0] <= #1 2'b0; // clear IRQ_ACK bit`
219			`end`
220
221
222			`// decode command register`
223			`wire sta = cr[7];`
224			`wire sto = cr[6];`
225			`wire rd = cr[5];`
226			`wire wr = cr[4];`
227			`wire ack = cr[3];`
228			`wire iack = cr[0];`
229
230			`// decode control register`
231			`assign core_en = ctr[7];`
232			`assign ien = ctr[6];`
233
234			`// hookup byte controller block`
235			`i2c_master_byte_ctrl byte_controller (`
236			`.clk ( wb_clk_i ),`
237			`.rst ( wb_rst_i ),`
238			`.nReset ( rst_i ),`
239			`.ena ( core_en ),`
240			`.clk_cnt ( prer ),`
241			`.start ( sta ),`
242			`.stop ( sto ),`
243			`.read ( rd ),`
244			`.write ( wr ),`
245			`.ack_in ( ack ),`
246			`.din ( txr ),`
247			`.cmd_ack ( done ),`
248			`.ack_out ( irxack ),`
249			`.dout ( rxr ),`
250			`.i2c_busy ( i2c_busy ),`
251			`.i2c_al ( i2c_al ),`
252			`.scl_i ( scl_pad_i ),`
253			`.scl_o ( scl_pad_o ),`
254			`.scl_oen ( scl_padoen_o ),`
255			`.sda_i ( sda_pad_i ),`
256			`.sda_o ( sda_pad_o ),`
257			`.sda_oen ( sda_padoen_o )`
258			`);`
259
260			`// status register block + interrupt request signal`
261			`always @(posedge wb_clk_i or negedge rst_i)`
262			`if (!rst_i)`
263			`begin`
264			`al <= #1 1'b0;`
265			`rxack <= #1 1'b0;`
266			`tip <= #1 1'b0;`
267			`irq_flag <= #1 1'b0;`
268			`end`
269			`else if (wb_rst_i)`
270			`begin`
271			`al <= #1 1'b0;`
272			`rxack <= #1 1'b0;`
273			`tip <= #1 1'b0;`
274			`irq_flag <= #1 1'b0;`
275			`end`
276			`else`
277			`begin`
278			`al <= #1 i2c_al \| (al & ~sta);`
279			`rxack <= #1 irxack;`
280			`tip <= #1 (rd \| wr);`
281			`irq_flag <= #1 (done \| i2c_al \| irq_flag) & ~iack; // interrupt request flag is always generated`
282			`end`
283
284			`// generate interrupt request signals`
285			`always @(posedge wb_clk_i or negedge rst_i)`
286			`if (!rst_i)`
287			`wb_inta_o <= #1 1'b0;`
288			`else if (wb_rst_i)`
289			`wb_inta_o <= #1 1'b0;`
290			`else`
291			`wb_inta_o <= #1 irq_flag && ien; // interrupt signal is only generated when IEN (interrupt enable bit is set)`
292
293			`// assign status register bits`
294			`assign sr[7] = rxack;`
295			`assign sr[6] = i2c_busy;`
296			`assign sr[5] = al;`
297			`assign sr[4:2] = 3'h0; // reserved`
298			`assign sr[1] = tip;`
299			`assign sr[0] = irq_flag;`
300
301			`endmodule`