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[/] [System09/] [trunk/] [rtl/] [System09_BurchED_B3/] [System09_BurchED_B3.vhd] - Blame information for rev 114

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1 107 davidgb
--=============================================================================--
2
--                                                                             --
3
--  System09 - Synthesizable System On a Chip - VHDL FPGA core top level file. --
4
--                                                                             --
5
--=============================================================================--
6
--
7
-- File name      : System09_BurchED_B3.vhd
8
--
9
-- Purpose        : This is the top level file for a 6809 instruction compatible system on a chip 
10
--                  It has been designed for the BurchED B3 Spartan2+ FPGA board
11
--                  using the Xilinx XC2S200 Spartan 2 FPGA and Xilinx ISE 7.1 software.
12
--                  It has been implemented with the BurchED B3 FPGA board, 
13
--                  modified B3-SRAM module and B3-FPGA-CPU-IO module. 
14
--                  It also supports an IDE CF card interface using a CF to IDE interface adapter.
15
--                  It uses a monochrome version of the VDU due to limitted Block RAM of XC2S200
16
--
17
-- Dependencies   : ieee.Std_Logic_1164
18
--                  ieee.std_logic_unsigned
19
--                  ieee.std_logic_arith
20
--                  ieee.numeric_std
21
--
22
-- Uses           : 
23
--                  clk_div        (..\Spartan2\clk_div.vhd)       System Clock Divider
24
--                  cpu09          (..\VHDL\cpu09.vhd)             CPU core
25
--                  B3_SRAM        (..\VHDL\B3_SRAM.vhd)           BurchED B3 SRAM module interface
26
--                  acia6850       (..\VHDL\acia6850.vhd)          RS232 Serial Interface
27
--                  ACIA_Clock     (..\VHDL\ACIA_Clock.vhd)        ACIA Baud Rate Clock Divider
28
--                  keyboard       (..\VHDL\keyboard.vhd)          PS/2 Keyboard register interface
29
--                  ps2_keyboard   (..\VHDL\ps2_keyboard.vhd)      PS/2 Keyboard interface logic
30
--                  keymap_rom     (..\Spartan2\keymap_rom_b4.vhd) PS/2 Keyboard key code look up table
31
--                  vdu8_mono      (..\VHDL\vdu8_mono.vhd)         80 x 25 Monochrome Visual Display Unit.
32
--                  char_rom       (..\Spartan2\char_rom2k_b4.vhd) Character Generator ROM
33
--                  ram_2k         (..\Spartan2\ram2k_b4.vhd)      Text buffer RAM
34
--                  timer          (..\VHDL\timer.vhd)             Timer module
35
--                  trap           (..\VHDL\trap.vhd)              Bus Trap interrupt
36
--                  spp            (..\VHDL\spp.vhd)               Simple Parallel Port
37
--                  peripheral_bus (..\VHDL\peripheral_bus.vhd)    16 bit IDE Peripheral Bus interface
38
--                  sys09bug_F800  (..\Spartan2\sys09b3s_b4.vhd)   Sysbug09 Monitor ROM
39
--                  dat_ram        (..\VHDL\datram.vhd)            Dynamic Address Translation (DAT)
40
-- 
41
-- Author         : John E. Kent      
42
--                  dilbert57@opencores.org
43
--
44
-- Memory Map     :
45
--
46
-- $0000 - $DFFF System RAM (256K Mapped via DAT)
47
-- $E000 - ACIA (SWTPc)
48
-- $E010 - Reserved for SWTPc FD-01 FD1771 FDC
49
-- $E020 - Keyboard
50
-- $E030 - VDU
51
-- $E040 - Reserved for SWTPc MP-T (was Compact Flash)
52
-- $E050 - Timer
53
-- $E060 - Bus Trap (Hardware Breakpoint Interrupt Logic)
54
-- $E070 - Reserved for Trace Buffer
55
-- $E080 - Reserved for SWTPc MP-ID 6821 PIA (?)
56
-- $E090 - Reserved for SWTPc MP-ID 6840 PTM (?)
57
-- $E0A0 - SPP Printer Port
58
-- $E0B0 - Reserved
59
-- $E0C0 - Reserved
60
-- $E100 - $E13F IDE / Compact Flash Card
61
-- $E140 - $E17F Reserved for Ethernet MAC (XESS)
62
-- $E180 - $E1BF Reserved for Expansion Slot 0 (XESS)
63
-- $E1C0 - $E1FF Reserved for Expansion Slot 1 (XESS)
64
-- $E200 - $EFFF Dual Port RAM interface
65
-- $F000 - $F7FF Reserved SWTPc DMAF-2
66
-- $F800 - $FFFF Sys09bug ROM (Read only)
67
-- $FFF0 - $FFFF DAT - Dynamic Address Translation (Write Only)
68
--
69
--
70
--  Copyright (C) 2003 - 2010 John Kent
71
--
72
--  This program is free software: you can redistribute it and/or modify
73
--  it under the terms of the GNU General Public License as published by
74
--  the Free Software Foundation, either version 3 of the License, or
75
--  (at your option) any later version.
76
--
77
--  This program is distributed in the hope that it will be useful,
78
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
79
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
80
--  GNU General Public License for more details.
81
--
82
--  You should have received a copy of the GNU General Public License
83
--  along with this program.  If not, see <http://www.gnu.org/licenses/>.
84
--
85
--===========================================================================--
86
--
87
--                         Revision History:
88
--
89
--===========================================================================--
90
-- Version 0.1 - 20 March 2003
91
-- Version 0.2 - 30 March 2003
92
-- Version 0.3 - 29 April 2003
93
-- Version 0.4 - 29 June 2003
94
--
95
-- Version 0.5 - 19 July 2003
96
-- prints out "Hello World"
97
--
98
-- Version 0.6 - 5 September 2003
99
-- Runs SBUG
100
--
101
-- Version 1.0- 6 Sep 2003 - John Kent
102
-- Inverted SysClk
103
-- Initial release to Open Cores
104
--
105
-- Version 1.1 - 17 Jan 2004 - John Kent
106
-- Updated miniUart.
107
--
108
-- Version 1.2 - 25 Jan 2004 - John Kent
109
-- removed signals "test_alu" and "test_cc" 
110
-- Trap hardware re-instated.
111
--
112
-- Version 1.3 - 11 Feb 2004 - John Kent
113
-- Designed forked off to produce System09_VDU
114
-- Added VDU component
115
--      VDU runs at 25MHz and divides the clock by 2 for the CPU
116
-- UART Runs at 57.6 Kbps
117
--
118
-- Version 1.4 - 21 Nov 2004 - John Kent
119
-- Changes to make compatible with Spartan3 starter kit version
120
-- Designed to run with a 50MHz clock input.
121
-- the VDU divides 50 MHz to generate a 
122
-- 25 MHz VDU Pixel Clock and a 12.5 MHz CPU clock
123
-- Changed Monitor ROM signals to make it look like
124
-- a standard 2K memory block
125
-- Re-assigned I/O port assignments so it is possible to run KBUG9
126
--
127
-- Version 1.5 - 3rd February 2007 - John Kent
128
-- Changed VDU8 to use external clock divider
129
-- renamed miniUART to ACIA_6850
130
-- Memory decoding of ROM & IO now uses DAT
131
--
132
-- Version 1.6 - 7th Februaury 2007 - John Kent
133
-- Made ACIA Clock generator an external component
134
-- Added Generics to VDU and Keyboard
135
-- Changed decoding
136
--
137
-- Version 1.7 - 20th May 2007 - John Kent
138
-- Added 4 wait states to CF access
139
-- Removed DAT memory map control of ROM & IO
140
-- to allow for full use of RAM as a RAM disk.
141
-- Mapped in all 16 bits of the CF data bus.
142
--
143
-- Version 1.8 - 1st July 2007 - John Kent
144
-- Copied B5-X300 top level to B3 version.
145
--
146
-- Version 2.0 - 6th September 2008 - John Kent
147
-- added IDE interface for a CF card.
148
-- Used separate Clock DLL for generating clocks
149
--
150
-- Version 2.1 - 23rd Februaury 2008 - John Kent
151
-- Renamed Monitor ROM
152
--
153
-- Version 2.2 - 28th August 2010 - John Kent
154
-- Renamed ACIA_6850 to acia6850
155
-- Updated CPU & VDU component signal names & generics
156
-- Made peripheral bus interface a separate component
157
-- Made BED_SRAM a separate component
158
-- Made the LED flasher a separate component
159
-- Updated Header
160
--
161
--===========================================================================
162
--
163
library ieee;
164
   use ieee.std_logic_1164.all;
165
   use IEEE.STD_LOGIC_ARITH.ALL;
166
   use IEEE.STD_LOGIC_UNSIGNED.ALL;
167
   use ieee.numeric_std.all;
168
library unisim;
169
   use unisim.vcomponents.all;
170
 
171
entity System09 is
172
  port(
173
    clk_in      : in  Std_Logic;  -- System Clock input
174
    rst_n       : in  Std_logic;  -- Master Reset input (active low)
175
    LED         : out Std_logic;  -- Diagnostic LED Flasher
176
 
177
    -- B3-SRAM Memory Interface signals
178
 
179
    ram_csn     : out Std_Logic;
180
    ram_wrln    : out Std_Logic;
181
    ram_wrun    : out Std_Logic;
182
    ram_addr    : out Std_Logic_Vector(16 downto 0);
183
    ram_data    : inout Std_Logic_Vector(15 downto 0);
184
 
185
    -- End of B3-SRAM Memory Interface signals
186
 
187
    -- B3-FPGA-CPU-IO Module signals
188
 
189
    -- Asychronous Communications Interface Adapater signals (RS232 Serial Port) ($E00X)
190
    acia_rxd    : in  Std_Logic;
191
    acia_txd    : out Std_Logic;
192
    acia_rts_n  : out Std_Logic;
193
    acia_cts_n  : in  Std_Logic;
194
 
195
    -- PS/2 Keyboard Interface ($E02X)
196
    kb_clock    : inout Std_logic;
197
    kb_data     : inout Std_Logic;
198
 
199
        -- PS/2 Mouse interface
200
--       mouse_clock : in  Std_Logic;
201
--       mouse_data  : in  Std_Logic;
202
 
203
    -- Visual Display Unit output signals ($E03X)
204
    vga_vsync   : out Std_Logic;
205
    vga_hsync   : out Std_Logic;
206
    vga_blue    : out std_logic_vector(1 downto 0);
207
    vga_green   : out std_logic_vector(1 downto 0);
208
    vga_red     : out std_logic_vector(1 downto 0);
209
 
210
    -- Buzzer
211
--         buzzer      : out std_logic;
212
 
213
    -- End of B3-FPGA-CPU-IO Module signals
214
 
215
    -- Parallel Printer Port    ($E0AX)
216
    pp_data      : out std_logic_vector(7 downto 0);
217
    pp_stat      : in  std_logic_vector(7 downto 3);
218
    pp_ctrl      : out std_logic_vector(3 downto 0);
219
 
220
    -- Peripheral Bus ($E100 - $E1FF) 
221
    pb_iord_n    : out std_logic;
222
    pb_iowr_n    : out std_logic;
223
    pb_addr      : out std_logic_vector(2 downto 0);
224
    pb_data      : inout std_logic_vector(15 downto 0);
225
 
226
    -- IDE Compact Flash ($E100 - $E13F)
227
    ide_rst_n    : out std_logic; -- ide pin 1
228
    ide_cs0_n    : out std_logic; -- ide pin 37
229
    ide_cs1_n    : out std_logic; -- ide pin 38
230
    ide_dmarq    : in  std_logic; -- ide pin 21
231
    ide_dmack_n  : out std_logic; -- ide pin 29
232
    ide_iordy    : in  std_logic; -- ide pin 27
233
    ide_con_csel : out std_logic; -- ide pin 28
234
    ide_intrq    : in  std_logic; -- ide pin 31
235
    ide_iocs16_n : in  std_logic; -- ide pin 32
236
    ide_pdiag_n  : in  std_logic; -- ide pin 34
237
    ide_dasp_n   : out std_logic; -- ide pin 39
238
 
239
    -- Dual port RAM interface bus
240
    bus_clk      : in  std_logic;
241
    bus_cs_n     : in  std_logic;
242
    bus_rw       : in  std_logic;
243
    bus_addr     : in  std_logic_vector(12 downto 0);
244
    bus_data_in  : in  std_logic_vector(7 downto 0);
245
    bus_data_out : out std_logic_vector(7 downto 0)
246
 );
247
end System09;
248
 
249
-------------------------------------------------------------------------------
250
-- Architecture for System09
251
-------------------------------------------------------------------------------
252
architecture rtl of System09 is
253
  -----------------------------------------------------------------------------
254
  -- constants
255
  -----------------------------------------------------------------------------
256
  constant SYS_CLK_FREQ  : integer := 50000000;  -- FPGA System Clock
257
  constant VGA_CLK_FREQ  : integer := 25000000;  -- VGA Pixel Clock
258
  constant CPU_CLK_FREQ  : integer := 12500000;  -- CPU Clock
259
  constant BAUD_RATE     : integer := 57600;      -- Baud Rate
260
  constant ACIA_CLK_FREQ : integer := BAUD_RATE * 16;
261
 
262
  -----------------------------------------------------------------------------
263
  -- Signals
264
  -----------------------------------------------------------------------------
265
 
266
  -- System Clock
267
  signal sys_clk       : std_logic;
268
 
269
  -- CPU Interface signals
270
  signal cpu_rst       : Std_Logic;
271
  signal cpu_clk       : Std_Logic;
272
  signal cpu_rw        : std_logic;
273
  signal cpu_vma       : std_logic;
274
  signal cpu_halt      : std_logic;
275
  signal cpu_hold      : std_logic;
276
  signal cpu_firq      : std_logic;
277
  signal cpu_irq       : std_logic;
278
  signal cpu_nmi       : std_logic;
279
  signal cpu_addr      : std_logic_vector(15 downto 0);
280
  signal cpu_data_in   : std_logic_vector(7 downto 0);
281
  signal cpu_data_out  : std_logic_vector(7 downto 0);
282
 
283
  -- B3 Static RAM            ($0000 - $DFFF)
284
  signal ram_cs        : std_logic; -- memory chip select
285
  signal ram_data_out  : std_logic_vector(7 downto 0);
286
 
287
  -- ACIA Console serial port ($E000 - $E00F)
288
  signal acia_data_out : Std_Logic_Vector(7 downto 0);
289
  signal acia_cs       : Std_Logic;
290
  signal acia_irq      : Std_Logic;
291
  signal acia_clk      : Std_Logic;
292
 
293
  -- PS/2 Keyboard interface  ($E02X)
294
  signal kbd_data_out  : std_logic_vector(7 downto 0);
295
  signal kbd_cs        : std_logic;
296
  signal kbd_irq       : std_logic;
297
 
298
  -- Visual Display Unit      ($E03X)
299
  signal vga_clk       : std_logic;
300
  signal vdu_cs        : std_logic;
301
  signal vdu_data_out  : std_logic_vector(7 downto 0);
302
  signal vga_red_o     : std_logic;
303
  signal vga_green_o   : std_logic;
304
  signal vga_blue_o    : std_logic;
305
 
306
  -- Timer                    ($E05X)
307
  signal timer_data_out : std_logic_vector(7 downto 0);
308
  signal timer_cs      : std_logic;
309
  signal timer_irq     : std_logic;
310
 
311
  -- Bus trap                 ($E06X)
312
  signal trap_cs       : std_logic;
313
  signal trap_data_out : std_logic_vector(7 downto 0);
314
  signal trap_irq      : std_logic;
315
 
316
  -- Trace                    ($E07X)
317
--  signal trace_cs       : std_logic;
318
--  signal trace_data_out : std_logic_vector(7 downto 0);
319
--  signal trace_irq      : std_logic;
320
 
321
  -- Simple Parallel I/O port ($E0AX)
322
  signal spp_data_out  : std_logic_vector(7 downto 0);
323
  signal spp_cs        : std_logic;
324
 
325
  -- Peripheral Bus           ($E1XX)
326
  signal pb_cs         : std_logic;
327
  signal pb_data_out   : std_logic_vector(7 downto 0);
328
  signal pb_hold       : std_logic;
329
 
330
  -- Peripheral Bus Chip Selects ($E1XX)
331
  signal ide_cs        : std_logic;      -- IDE CF interface   ($E100 - $E13F)
332
  signal ether_cs      : std_logic;  -- Ethernet interface ($E140 - $E17F)      
333
  signal slot1_cs      : std_logic;      -- Expansion slot1    ($E180 - $E1BF)
334
  signal slot2_cs      : std_logic;      -- Expansion slot 2   ($E1C0 - $E1FF)
335
 
336
  -- Dual Port RAM for Bus Interfacing  ($E200 - $E7FF)
337
  signal dpr_data_out  : std_logic_vector(7 downto 0);
338
  signal dpr_cs        : std_logic;
339
  signal dpr_wr        : std_logic;
340
 
341
  -- External Bus Interface
342
  signal bus_iclk     : std_logic;
343
  signal bus_gclk     : std_logic;
344
  signal bus_cs       : std_logic;
345
  signal bus_wr       : std_logic;
346
 
347
  -- Monitor ROM ($F800 - $FFFF)
348
  signal rom_data_out  : Std_Logic_Vector(7 downto 0);
349
  signal rom_cs        : std_logic;
350
 
351
  -- Dynamic Address Translation        ($FFF0 - $FFFF)
352
  signal dat_cs       : std_logic;
353
  signal dat_addr     : std_logic_vector(7 downto 0);
354
 
355
-----------------------------------------------------------------
356
--
357
--                     Clock generator
358
--
359
-----------------------------------------------------------------
360
 
361
component clock_div
362
  port(
363
    clk_in      : in  std_Logic;  -- System Clock input
364
         sys_clk     : out std_logic;  -- System Clock Out    (1/1)
365
         vga_clk     : out std_logic;  -- VGA Pixel Clock Out (1/2)
366
    cpu_clk     : out std_logic   -- CPU Clock Out       (1/4)
367
  );
368
end component;
369
 
370
-----------------------------------------------------------------
371
--
372
--                      LED Flasher
373
--
374
-----------------------------------------------------------------
375 19 dilbert57
 
376 107 davidgb
component flasher
377 19 dilbert57
  port (
378 107 davidgb
    clk      : in  std_logic;           -- Clock input
379
    rst      : in  std_logic;           -- Reset input (active high)
380
    LED      : out Std_Logic            -- LED output        
381 19 dilbert57
  );
382 107 davidgb
end component;
383
 
384
 
385
-----------------------------------------------------------------
386
--
387
--                  6809 Compatible CPU core
388
--
389
-----------------------------------------------------------------
390
 
391
component cpu09
392
  port (
393
    clk       : in  std_logic;
394
    rst       : in  std_logic;
395
    rw        : out std_logic;
396
    vma       : out std_logic;
397
    addr      : out std_logic_vector(15 downto 0);
398
    data_in   : in  std_logic_vector(7 downto 0);
399
    data_out  : out std_logic_vector(7 downto 0);
400
    halt      : in  std_logic;
401
    hold      : in  std_logic;
402
    irq       : in  std_logic;
403
    nmi       : in  std_logic;
404
    firq      : in  std_logic
405
  );
406
end component;
407 19 dilbert57
 
408 107 davidgb
-----------------------------------------------------------------
409
--
410
-- Dynamic Address Translation Registers ($FFF0 - $FFFF)
411
--
412
-----------------------------------------------------------------
413
component dat_ram
414
  port (
415
    clk      : in  std_logic;
416
    rst      : in  std_logic;
417
    cs       : in  std_logic;
418
    rw       : in  std_logic;
419
    addr_lo  : in  std_logic_vector(3 downto 0);
420
    addr_hi  : in  std_logic_vector(3 downto 0);
421
    data_in  : in  std_logic_vector(7 downto 0);
422
    data_out : out std_logic_vector(7 downto 0)
423
  );
424
end component;
425
 
426
-------------------------------------------------
427
--
428
-- Sys09Bug Block RAM Monitor ROM ($F800-$FFFF)
429
--
430
-------------------------------------------------
431
component sys09bug_F800
432
  port (
433
     clk      : in  std_logic;
434
     rst      : in  std_logic;
435
     cs       : in  std_logic;
436
     addr     : in  std_logic_vector (10 downto 0);
437
     rw       : in  std_logic;
438
     data_in  : in  std_logic_vector (7 downto 0);
439
     data_out : out std_logic_vector (7 downto 0)
440
  );
441
end component;
442
 
443
-----------------------------------------------------------------
444
--
445
-- 6850 ACIA RS232 Interface  ($E000 - $E00F)
446
--
447
-----------------------------------------------------------------
448
 
449
component acia6850
450
  port (
451
     clk      : in  Std_Logic;  -- System Clock
452
     rst      : in  Std_Logic;  -- Reset input (active high)
453
     cs       : in  Std_Logic;  -- miniUART Chip Select
454
     rw       : in  Std_Logic;  -- Read / Not Write
455
     irq      : out Std_Logic;  -- Interrupt
456
     addr     : in  Std_Logic;  -- Register Select
457
     data_in  : in  Std_Logic_Vector(7 downto 0); -- Data Bus In 
458
     data_out : out Std_Logic_Vector(7 downto 0); -- Data Bus Out
459
     RxC      : in  Std_Logic;  -- Receive Baud Clock
460
     TxC      : in  Std_Logic;  -- Transmit Baud Clock
461
     RxD      : in  Std_Logic;  -- Receive Data
462
     TxD      : out Std_Logic;  -- Transmit Data
463
     DCD_n    : in  Std_Logic;  -- Data Carrier Detect
464
     CTS_n    : in  Std_Logic;  -- Clear To Send
465
     RTS_n    : out Std_Logic );  -- Request To send
466
end component;
467
 
468
-----------------------------------------------------------------
469
--
470
-- ACIA Clock divider
471
--
472
-----------------------------------------------------------------
473
 
474
component ACIA_Clock
475
  generic (
476
     SYS_CLK_FREQ  : integer := SYS_CLK_FREQ;
477
     ACIA_CLK_FREQ : integer := ACIA_CLK_FREQ
478
  );
479
  port (
480
     clk      : in  Std_Logic;  -- System Clock Input
481
     acia_clk : out Std_logic   -- ACIA Clock output
482
  );
483
end component;
484
 
485
----------------------------------------
486
--
487
-- PS/2 Keyboard ($E020 - $E02F)
488
--
489
----------------------------------------
490
 
491
component keyboard
492
  generic(
493
     KBD_CLK_FREQ : integer := CPU_CLK_FREQ
494
  );
495
  port (
496
     clk         : in    std_logic;
497
     rst         : in    std_logic;
498
     cs          : in    std_logic;
499
     rw          : in    std_logic;
500
     addr        : in    std_logic;
501
     data_in     : in    std_logic_vector(7 downto 0);
502
     data_out    : out   std_logic_vector(7 downto 0);
503
     irq         : out   std_logic;
504
     kbd_clk     : inout std_logic;
505
     kbd_data    : inout std_logic
506
  );
507
end component;
508
 
509
----------------------------------------
510
--
511
-- Video Display Unit. ($E030 - $E03F)
512
--
513
----------------------------------------
514
component vdu8_mono
515
  generic(
516
    VGA_CLK_FREQ           : integer := VGA_CLK_FREQ; -- HZ
517
         VGA_HOR_CHARS          : integer := 80; -- CHARACTERS 25.6us
518
         VGA_HOR_CHAR_PIXELS    : integer := 8;  -- PIXELS 0.32us
519
         VGA_HOR_FRONT_PORCH    : integer := 16; -- PIXELS 0.64us
520
         VGA_HOR_SYNC           : integer := 96; -- PIXELS 3.84us
521
         VGA_HOR_BACK_PORCH     : integer := 48; -- PIXELS 1.92us
522
         VGA_VER_CHARS          : integer := 25; -- CHARACTERS 12.8ms
523
         VGA_VER_CHAR_LINES     : integer := 16; -- LINES 0.512ms
524
         VGA_VER_FRONT_PORCH    : integer := 10; -- LINES 0.320ms
525
         VGA_VER_SYNC           : integer := 2;  -- LINES 0.064ms
526
         VGA_VER_BACK_PORCH     : integer := 34  -- LINES 1.088ms
527
  );
528
  port(
529
    -- control register interface
530
    vdu_clk      : in  std_logic;        -- CPU Clock - 12.5MHz
531
    vdu_rst      : in  std_logic;
532
    vdu_cs       : in  std_logic;
533
    vdu_addr     : in  std_logic_vector(2 downto 0);
534
    vdu_rw       : in  std_logic;
535
    vdu_data_in  : in  std_logic_vector(7 downto 0);
536
    vdu_data_out : out std_logic_vector(7 downto 0);
537
 
538
    -- vga port connections
539
    vga_clk      : in  std_logic;       -- VGA Pixel Clock - 25 MHz
540
    vga_red_o    : out std_logic;
541
    vga_green_o  : out std_logic;
542
    vga_blue_o   : out std_logic;
543
    vga_hsync_o  : out std_logic;
544
    vga_vsync_o  : out std_logic
545
  );
546
end component;
547
 
548
----------------------------------------
549
--
550
-- Timer module  ($E050 - $E05F)
551
--
552
----------------------------------------
553
 
554
component timer
555
  port (
556
    clk       : in std_logic;
557
    rst       : in std_logic;
558
    cs        : in std_logic;
559
    addr      : in std_logic;
560
    rw        : in std_logic;
561
    data_in   : in std_logic_vector(7 downto 0);
562
    data_out  : out std_logic_vector(7 downto 0);
563
    irq       : out std_logic
564
  );
565
end component;
566
 
567
------------------------------------------------------------
568
--
569
-- Bus Trap / Hardware Breakpoint ($E060 - $E06F)
570
--
571
------------------------------------------------------------
572
 
573
component trap
574
  port (
575
    clk        : in  std_logic;
576
    rst        : in  std_logic;
577
    cs         : in  std_logic;
578
    rw         : in  std_logic;
579
    vma        : in  std_logic;
580
    addr       : in  std_logic_vector(15 downto 0);
581
    data_in    : in  std_logic_vector(7 downto 0);
582
    data_out   : out std_logic_vector(7 downto 0);
583
    irq        : out std_logic
584
  );
585
end component;
586
 
587
------------------------------------------------------------
588
--
589
-- Bus Trace logic      ($E070 - $E07F)
590
--
591
------------------------------------------------------------
592
--component trace is
593
--  port (      
594
--    clk           : in  std_logic;
595
--    rst           : in  std_logic;
596
--    rs            : in  std_logic;      -- register select
597
--    bs            : in  std_logic;      -- bank select
598
--    rw            : in  std_logic;
599
--    vma           : in  std_logic;
600
--    addr          : in  std_logic_vector(15 downto 0);
601
--    data_in       : in  std_logic_vector(7 downto 0);
602
--    reg_data_out  : out std_logic_vector(7 downto 0);
603
--    buff_data_out : out std_logic_vector(7 downto 0);
604
--    cpu_data_in   : in  std_logic_vector(7 downto 0);
605
--    irq           : out std_logic
606
--  );
607
--end component;
608
 
609
----------------------------------------
610
--
611
-- Simple Parallel Port ($E0A0 - $E0AF)
612
--
613
----------------------------------------
614
component spp
615
  port (
616
    clk       : in  std_logic;
617
    rst       : in  std_logic;
618
    cs        : in  std_logic;
619
    addr      : in  std_logic_vector(2 downto 0);
620
    rw        : in  std_logic;
621
    data_in   : in  std_logic_vector(7 downto 0);
622
    data_out  : out std_logic_vector(7 downto 0);
623
    irq       : out std_logic;
624
    hold      : out std_logic;
625
    spp_data  : out std_logic_vector(7 downto 0);
626
    spp_stat  : in  std_logic_vector(7 downto 3);
627
    spp_ctrl  : out std_logic_vector(3 downto 0)
628
   );
629
end component;
630
 
631
------------------------------------------------------------
632
--
633
-- Peripheral Bus interface (IDE CF) ($E100 - $E1FF)
634
--
635
------------------------------------------------------------
636 19 dilbert57
 
637 107 davidgb
component peripheral_bus is
638 19 dilbert57
  port (
639 107 davidgb
    --
640
    -- CPU Interface signals
641
    --
642
    clk      : in  std_logic;                     -- System Clock
643
    rst      : in  std_logic;                     -- Reset input (active high)
644
    cs       : in  std_logic;                     -- Peripheral Bus Chip Select
645
    addr     : in  std_logic_vector(7 downto 0);  -- Register Select
646
    rw       : in  std_logic;                     -- Read / Not Write
647
    data_in  : in  std_logic_vector(7 downto 0);  -- Data Bus In 
648
    data_out : out std_logic_vector(7 downto 0);  -- Data Bus Out
649
    hold     : out std_logic;                     -- Hold bus cycle output
650
    --
651
    -- Peripheral Bus Interface Signals
652
    -- IO + ($00 - $FF) 
653
    -- (for compatibility with XSA-3S1000 / XST 3.0)
654
    --
655
    pb_rd_n  : out   std_logic; -- ide pin 25
656
    pb_wr_n  : out   std_logic; -- ide pin 23
657
    pb_addr  : out   std_logic_vector( 4 downto 0);
658
    pb_data  : inout std_logic_vector(15 downto 0);
659
 
660
    -- Peripheral chip selects on Peripheral Bus 
661
    ide_cs   : out  std_logic;  -- IDE / CF interface ($00 - $3F)
662
    eth_cs   : out  std_logic;  -- Ethernet interface ($40 - $7F)
663
    sl1_cs   : out  std_logic;  -- Expansion slot 1   ($80 - $BF)
664
    sl2_cs   : out  std_logic   -- Expansion slot 2   ($C0 - $FF)
665
    );
666
end component;
667
 
668
------------------------------------------------------------
669
--
670
-- External Bus interface Dual port RAM ($E200 - $EFFF)
671
--
672
------------------------------------------------------------
673
 
674
component RAMB4_S8_S8
675
port (
676
  RSTA:  IN  std_logic;
677
  CLKA:  IN  std_logic;
678
  ENA:   IN  std_logic;
679
  WEA:   IN  std_logic;
680
  ADDRA: IN  std_logic_vector(8 downto 0);
681
  DIA:   IN  std_logic_vector(7 downto 0);
682
  DOA:   OUT std_logic_vector(7 downto 0);
683
  RSTB:  IN  std_logic;
684
  CLKB:  IN  std_logic;
685
  ENB:   IN  std_logic;
686
  WEB:   IN  std_logic;
687
  ADDRB: IN  std_logic_vector(8 downto 0);
688
  DIB:   IN  std_logic_vector(7 downto 0);
689
  DOB:   OUT std_logic_vector(7 downto 0)
690
  );
691
end component;
692
 
693
component IBUF
694
port (
695
  I : IN  std_logic;
696
  O : OUT std_logic
697
  );
698
end component;
699
 
700
component BUFG
701
port (
702
  I : IN  std_logic;
703
  O : OUT std_logic
704
  );
705
end component;
706
 
707
------------------------------------------------------------
708
--
709
--           BED SRAM interface ($0000 - $DFFF)
710
--
711
------------------------------------------------------------
712
component BED_SRAM
713 19 dilbert57
  port (
714 107 davidgb
    --
715
    -- CPU Interface signals
716
    --
717
    clk       : in  std_logic;                     -- System Clock (twice the CPU clock)
718
    rst       : in  std_logic;                     -- Reset input (active high)
719
    cs        : in  std_logic;                     -- RAM Chip Select
720
    addr      : in  std_logic_vector(17 downto 0); -- RAM address bus
721
    rw        : in  std_logic;                     -- Read / Not Write
722
    data_in   : in  std_logic_vector(7 downto 0);  -- Data Bus In 
723
    data_out  : out std_logic_vector(7 downto 0);  -- Data Bus Out
724
    --
725
    -- B3_SRAM Interface Signals
726
    --
727
    ram_csn   : out   Std_Logic;
728
    ram_wrln  : out   Std_Logic;
729
    ram_wrun  : out   Std_Logic;
730
    ram_addr  : out   Std_Logic_Vector(16 downto 0);
731
    ram_data  : inout Std_Logic_Vector(15 downto 0)
732
 
733
    );
734
end component;
735
 
736
begin
737
-----------------------------------------------------------------------------
738
-- Instantiation of internal components
739
-----------------------------------------------------------------------------
740
----------------------------------------
741
--
742
-- Clock generator
743
--
744
----------------------------------------
745
my_clock_div: clock_div port map (
746
    clk_in   => clk_in,   -- Clock input
747
    sys_clk  => sys_clk,  -- System Clock Out    (1/1)
748
    vga_clk  => vga_clk,  -- VGA Pixel Clock Out (1/2)
749
    cpu_clk  => cpu_clk   -- CPU Clock Out       (1/4)
750
  );
751
 
752
-----------------------------------------
753
--
754
-- LED Flasher
755
--
756
-----------------------------------------
757 19 dilbert57
 
758 107 davidgb
my_LED_flasher : flasher port map (
759
    clk      => cpu_clk,
760
    rst      => cpu_rst,
761
    LED      => LED
762 19 dilbert57
  );
763 107 davidgb
 
764
----------------------------------------
765
--
766
-- CPU09 CPU Core
767
--
768
----------------------------------------
769
my_cpu : cpu09  port map (
770
    clk       => cpu_clk,
771
    rst       => cpu_rst,
772
    rw        => cpu_rw,
773
    vma       => cpu_vma,
774
    addr      => cpu_addr(15 downto 0),
775
    data_in   => cpu_data_in,
776
    data_out  => cpu_data_out,
777
    halt      => cpu_halt,
778
    hold      => cpu_hold,
779
    irq       => cpu_irq,
780
    nmi       => cpu_nmi,
781
    firq      => cpu_firq
782
  );
783
 
784
----------------------------------------
785
--
786
-- Dynamic Address Translation ($FFF0-$FFFF)
787
--
788
----------------------------------------
789
my_dat : dat_ram port map (
790
    clk        => cpu_clk,
791
    rst        => cpu_rst,
792
    cs         => dat_cs,
793
    rw         => cpu_rw,
794
    addr_hi    => cpu_addr(15 downto 12),
795
    addr_lo    => cpu_addr(3 downto 0),
796
    data_in    => cpu_data_out,
797
    data_out   => dat_addr(7 downto 0)
798
  );
799
 
800
----------------------------------------
801
--
802
-- SYS09BUG Monitor ROM ($F800-$FFFF)
803
--
804
----------------------------------------
805
my_rom : SYS09BUG_F800 port map (
806
       clk      => cpu_clk,
807
       rst      => cpu_rst,
808
       cs       => rom_cs,
809
       rw       => '1',
810
       addr     => cpu_addr(10 downto 0),
811
       data_in  => cpu_data_out,
812
       data_out => rom_data_out
813
    );
814
 
815
----------------------------------------
816
--
817
-- ACIA RS232 Serial interface ($E000-$E00F)
818
--
819
----------------------------------------
820
my_ACIA  : acia6850 port map (
821
    --
822
    -- CPU Interface
823
    --
824
    clk      => cpu_clk,
825
    rst       => cpu_rst,
826
    cs        => acia_cs,
827
    rw        => cpu_rw,
828
    irq       => acia_irq,
829
    addr      => cpu_addr(0),
830
    data_in   => cpu_data_out,
831
    data_out  => acia_data_out,
832
    --
833
    -- RS232 Interface
834
    --
835
    RxC       => acia_clk,
836
    TxC       => acia_clk,
837
    RxD       => acia_rxd,
838
    TxD       => acia_txd,
839
    DCD_n     => '0',
840
    CTS_n     => acia_cts_n,
841
    RTS_n     => acia_rts_n
842
  );
843
 
844
----------------------------------------
845
--
846
-- ACIA Baud Clock
847
--
848
----------------------------------------
849
my_ACIA_Clock : ACIA_Clock
850
  generic map(
851
    SYS_CLK_FREQ  => SYS_CLK_FREQ,
852
    ACIA_CLK_FREQ => ACIA_CLK_FREQ
853
  )
854
  port map(
855
    clk        => sys_clk,
856
    acia_clk   => acia_clk
857
  );
858
 
859
----------------------------------------
860
--
861
-- PS/2 Keyboard Interface ($E020-$E02F)
862
--
863
----------------------------------------
864
my_keyboard : keyboard
865
  generic map (
866
    KBD_CLK_FREQ => CPU_CLK_FREQ
867
  )
868
  port map(
869
    clk          => cpu_clk,
870
    rst          => cpu_rst,
871
    cs           => kbd_cs,
872
    rw           => cpu_rw,
873
    addr         => cpu_addr(0),
874
    data_in      => cpu_data_out(7 downto 0),
875
    data_out     => kbd_data_out(7 downto 0),
876
    irq          => kbd_irq,
877
    kbd_clk      => kb_clock,
878
    kbd_data     => kb_data
879
  );
880
 
881
------------------------------------------------
882
--
883
-- Video Display Unit instantiation ($E030-$E03F)
884
--
885
-------------------------------------------------
886
my_vdu : vdu8_mono
887
  generic map(
888
    VGA_CLK_FREQ           => VGA_CLK_FREQ, -- 25MHZ
889
    VGA_HOR_CHARS          => 80, -- CHARACTERS 25.6us
890
    VGA_HOR_CHAR_PIXELS    => 8,  -- PIXELS 0.32us
891
    VGA_HOR_FRONT_PORCH    => 16, -- PIXELS 0.64us
892
    VGA_HOR_SYNC           => 96, -- PIXELS 3.84us
893
    VGA_HOR_BACK_PORCH     => 48, -- PIXELS 1.92us
894
    VGA_VER_CHARS          => 25, -- CHARACTERS 12.8ms
895
    VGA_VER_CHAR_LINES     => 16, -- LINES 0.512ms
896
    VGA_VER_FRONT_PORCH    => 10, -- LINES 0.320ms
897
    VGA_VER_SYNC           => 2,  -- LINES 0.064ms
898
    VGA_VER_BACK_PORCH     => 34  -- LINES 1.088ms
899
  )
900
  port map(
901
 
902
    -- CPU Control Registers interface
903
    vdu_clk       => cpu_clk,                                    -- 12.5 MHz System Clock in
904
    vdu_rst       => cpu_rst,
905
    vdu_cs        => vdu_cs,
906
    vdu_rw        => cpu_rw,
907
    vdu_addr      => cpu_addr(2 downto 0),
908
    vdu_data_in   => cpu_data_out,
909
    vdu_data_out  => vdu_data_out,
910
 
911
    -- vga port connections
912
    vga_clk       => vga_clk,                                    -- 25 MHz VDU pixel clock
913
    vga_red_o     => vga_red_o,
914
    vga_green_o   => vga_green_o,
915
    vga_blue_o    => vga_blue_o,
916
    vga_hsync_o   => vga_hsync,
917
    vga_vsync_o   => vga_vsync
918
  );
919
 
920
----------------------------------------
921
--
922
-- Timer Module
923
--
924
----------------------------------------
925
my_timer  : timer port map (
926
    clk       => cpu_clk,
927
    rst       => cpu_rst,
928
    cs        => timer_cs,
929
    rw        => cpu_rw,
930
    addr      => cpu_addr(0),
931
    data_in   => cpu_data_out,
932
    data_out  => timer_data_out,
933
    irq       => timer_irq
934
    );
935
 
936
----------------------------------------
937
--
938
-- Bus Trap Interrupt logic
939
--
940
----------------------------------------
941
my_trap : trap port map (
942
    clk        => cpu_clk,
943
    rst        => cpu_rst,
944
    cs         => trap_cs,
945
    rw         => cpu_rw,
946
    vma        => cpu_vma,
947
    addr       => cpu_addr,
948
    data_in    => cpu_data_out,
949
    data_out   => trap_data_out,
950
    irq        => trap_irq
951
    );
952
 
953
----------------------------------------
954
--
955
-- Bus Trace logic
956
--
957
----------------------------------------
958
--my_trace : trace port map (   
959
--    clk           => sys_clk,
960
--    rst           => cpu_rst,
961
--    rs            => trace_cs,
962
--    bs            => bank_cs,
963
--    rw            => cpu_rw,
964
--    vma           => cpu_vma,
965
--    addr          => cpu_addr,
966
--    data_in       => cpu_data_out,
967
--    reg_data_out  => trace_data_out,
968
--    buff_data_out => bank_data_out,
969
--    cpu_data_in   => cpu_data_in,
970
--    irq           => trace_irq
971
--    );
972
 
973
----------------------------------------
974
--
975
-- Simple Parallel Port
976
--
977
----------------------------------------
978
my_spp  : spp port map (
979
    clk       => cpu_clk,
980
    rst       => cpu_rst,
981
    cs        => spp_cs,
982
    rw        => cpu_rw,
983
    addr      => cpu_addr(2 downto 0),
984
    data_in   => cpu_data_out,
985
    data_out  => spp_data_out,
986
    spp_data  => pp_data,
987
    spp_stat  => pp_stat,
988
    spp_ctrl  => pp_ctrl,
989
    hold      => open,
990
    irq       => open
991
  );
992 19 dilbert57
 
993 107 davidgb
------------------------------------------------
994
--
995
-- 16 bit Peripheral Bus interface ($E100-$E1FF)
996
--
997
------------------------------------------------
998
my_pb : peripheral_bus port map (
999
    --
1000
    -- CPU Interface signals
1001
    --
1002 19 dilbert57
    clk       => cpu_clk,
1003 107 davidgb
    rst       => cpu_rst,
1004
    cs        => pb_cs,
1005
    addr      => cpu_addr(7 downto 0),
1006
    rw        => cpu_rw,
1007
    data_in   => cpu_data_out,
1008
    data_out  => pb_data_out,
1009
    hold      => pb_hold,
1010
    --
1011
    -- Peripheral Bus Interface Signals
1012
    -- IO + ($00 - $FF) 
1013
    --
1014
    pb_rd_n   => pb_iord_n,
1015
    pb_wr_n   => pb_iowr_n,
1016
    pb_addr(2 downto 0) => pb_addr,
1017
    pb_addr(4 downto 3) => open,
1018
    pb_data   => pb_data,
1019
 
1020
    -- Peripheral chip selects on Peripheral Bus 
1021
    ide_cs    => ide_cs,
1022
    eth_cs    => ether_cs,
1023
    sl1_cs    => slot1_cs,
1024
    sl2_cs    => slot2_cs
1025 19 dilbert57
    );
1026 107 davidgb
 
1027
------------------------------------------------------
1028
--
1029
-- External Bus interface Dual port RAM ($E200 - $EFFF)
1030
--
1031
-------------------------------------------------------
1032
my_dpr : RAMB4_S8_S8 port map (
1033
  RSTA  => cpu_rst,
1034
  CLKA  => cpu_clk,
1035
  ENA   => dpr_cs,
1036
  WEA   => dpr_wr,
1037
  ADDRA => cpu_addr(8 downto 0),
1038
  DIA   => cpu_data_out,
1039
  DOA   => dpr_data_out,
1040
  RSTB  => cpu_rst,
1041
  CLKB  => bus_gclk,
1042
  ENB   => bus_cs,
1043
  WEB   => bus_wr,
1044
  ADDRB => bus_addr(8 downto 0),
1045
  DIB   => bus_data_in,
1046
  DOB   => bus_data_out
1047
  );
1048
 
1049
my_dpr_ibuf : IBUF port map (
1050
  I     => bus_clk,
1051
  O     => bus_iclk
1052
  );
1053
 
1054
my_dpr_bufg : BUFG port map (
1055
  I     => bus_iclk,
1056
  O     => bus_gclk
1057
  );
1058
 
1059
-----------------------------------------------
1060
--
1061
-- BED SRAM interface (256KBytes) ($0000-$DFFF)
1062
--
1063
-----------------------------------------------
1064
my_bed_sram : BED_SRAM port map (
1065
    --
1066
    -- CPU Interface signals
1067
    --
1068
    clk       => vga_clk,                        -- VGA Clock (twice the CPU clock)
1069
    rst       => cpu_rst,                        -- Reset input (active high)
1070
    cs        => ram_cs,                         -- RAM Chip Select
1071
    addr(17 downto 12) => dat_addr( 5 downto 0), -- High RAM address goes to the DAT
1072
    addr(11 downto  0) => cpu_addr(11 downto 0), -- Low RAM address goes to the CPU
1073
    rw        => cpu_rw,                         -- Read / Not Write
1074
    data_in   => cpu_data_out,                   -- Data Bus In 
1075
    data_out  => ram_data_out,                   -- Data Bus Out
1076
    --
1077
    -- B3_SRAM Interface Signals
1078
    --
1079
    ram_csn   => ram_csn,
1080
    ram_wrln  => ram_wrln,
1081
    ram_wrun  => ram_wrun,
1082
    ram_addr  => ram_addr,
1083
    ram_data  => ram_data
1084 19 dilbert57
    );
1085 107 davidgb
 
1086
----------------------------------------------------------------------
1087
--
1088
-- Process to decode memory map
1089
--
1090
----------------------------------------------------------------------
1091
 
1092
my_decoder: process( cpu_addr, cpu_rw, cpu_vma,
1093
                     dat_addr,
1094
                     rom_data_out,
1095
                     acia_data_out,
1096
                     kbd_data_out,
1097
                     vdu_data_out,
1098
                     timer_data_out,
1099
                     trap_data_out,
1100
                     spp_data_out,
1101
                     dpr_data_out,
1102
                     pb_data_out,
1103
                     ram_data_out )
1104
begin
1105
   cpu_data_in <= (others=>'0');
1106
   dat_cs      <= '0';
1107
   rom_cs      <= '0';
1108
   acia_cs     <= '0';
1109
   kbd_cs      <= '0';
1110
   vdu_cs      <= '0';
1111
   timer_cs    <= '0';
1112
   trap_cs     <= '0';
1113
   spp_cs      <= '0';
1114
   dpr_cs      <= '0';
1115
   pb_cs       <= '0';
1116
   ram_cs      <= '0';
1117
 
1118
   if cpu_addr( 15 downto 8 ) = "11111111" then
1119
      --
1120
      -- Dynamic Address Translation $FFF0 - $FFFF
1121
      --
1122
      cpu_data_in <= rom_data_out;
1123
      dat_cs      <= cpu_vma;              -- write DAT
1124
      rom_cs      <= cpu_vma;              -- read  ROM
1125
 
1126
   elsif (dat_addr(3 downto 0) = "1111") and (cpu_addr(11) = '1') then -- $XF800 - $XFFFF
1127
      --
1128
      -- Sys09Bug Monitor ROM $F000 - $FFFF
1129
      --
1130
      cpu_data_in <= rom_data_out;
1131
      rom_cs      <= cpu_vma;
1132
 
1133
   elsif dat_addr(3 downto 0) = "1110" then -- $XE000 - $XEFFF
1134
      --
1135
      -- IO Devices $E000 - $E7FF
1136
      --
1137
      case cpu_addr(11 downto 8) is
1138
 
1139
      --
1140
      -- SWTPC peripherals from $E000 to $E0FF
1141
      --
1142
      when "0000" =>
1143
         case cpu_addr(7 downto 4) is
1144
         --
1145
         -- ACIA RS232 Console Port $E000 - $E00F
1146
         --
1147
         when "0000" => -- $E000
1148
            cpu_data_in <= acia_data_out;
1149
            acia_cs     <= cpu_vma;
1150
 
1151
         --
1152
         -- Reserved
1153
         -- Floppy Disk Controller port $E010 - $E01F
1154
         --
1155
         when "0001" => -- $E010
1156
            null;
1157
 
1158
         --
1159
         -- Keyboard port $E020 - $E02F
1160
         --
1161
         when "0010" => -- $E020
1162
            cpu_data_in <= kbd_data_out;
1163
            kbd_cs <= cpu_vma;
1164
 
1165
         --
1166
         -- VDU port $E030 - $E03F
1167
         --
1168
         when "0011" => -- $E030
1169
            cpu_data_in <= vdu_data_out;
1170
            vdu_cs      <= cpu_vma;
1171
 
1172
         --
1173
         -- Reserved SWTPc MP-T Timer $E040 - $E04F
1174
         --
1175
         when "0100" => -- $E040
1176
            cpu_data_in <= (others=> '0');
1177
 
1178
         --
1179
         -- Timer $E050 - $E05F
1180
         --
1181
         when "0101" => -- $E050
1182
            cpu_data_in <= timer_data_out;
1183
            timer_cs    <= cpu_vma;
1184
 
1185
         --
1186
         -- Bus Trap Logic $E060 - $E06F
1187
         --
1188
         when "0110" => -- $E060
1189
            cpu_data_in <= trap_data_out;
1190
            trap_cs     <= cpu_vma;
1191
 
1192
         --
1193
         -- Bus Trace Logic $E070 - $E07F
1194
         --
1195
--         when "0111" => -- $E070
1196
--            cpu_data_in <= trace_data_out;
1197
--            trace_cs    <= cpu_vma;
1198
 
1199
         --
1200
         -- Reserved SWTPc MP-ID PIA Timer/Printer Port $E080 - $E08F
1201
         --
1202
         when "1000" => -- $E080
1203
            null;
1204
 
1205
         --
1206
         -- Reserved SWTPc MP-ID PTM 6840 Timer Port $E090 - $E09F
1207
         --
1208
 
1209
         --
1210
         -- Simple Parallel Port $E0A0 - $E0AF
1211
         --
1212
         when "1010" => -- $E0A0
1213
            cpu_data_in <= spp_data_out;
1214
            spp_cs      <= cpu_vma;
1215
 
1216
         --
1217
         -- Remaining 5 slots reserved for non SWTPc Peripherals
1218
         --
1219
         when others => -- $E0B0 to $E0FF
1220
            cpu_data_in <= (others=> '0');
1221
 
1222
         end case;
1223
      --
1224
      -- XST-3.0 Peripheral Bus goes here
1225
      -- $E100 to $E1FF
1226
      -- Four devices
1227
      -- IDE, Ethernet, Slot1, Slot2
1228
      --
1229
      when "0001" =>
1230
         cpu_data_in <= pb_data_out;
1231
         pb_cs       <= cpu_vma;
1232
 
1233
      --
1234
      -- $E200 to $EFFF reserved for future use
1235
      --
1236
      when others =>
1237
         cpu_data_in <= dpr_data_out;
1238
         dpr_cs      <= cpu_vma;
1239
 
1240
      end case;
1241
 
1242
   --
1243
   -- Flex RAM $0C000 - $0DFFF
1244
   --
1245
-- elsif dat_addr(7 downto 1) = "0000110" then -- $0C000 - $0DFFF
1246
--    cpu_data_in <= flex_data_out;
1247
--    flex_cs     <= cpu_vma;
1248
 
1249
   --
1250
   -- Everything else is RAM
1251
   --
1252
   else
1253
      cpu_data_in <= ram_data_out;
1254
      ram_cs      <= cpu_vma;
1255
   end if;
1256
 
1257
end process;
1258
 
1259
--
1260
-- IDE drive / CF card signals ($E100 - $E13F)
1261
-- Located on peripheral bus
1262
--
1263
ide_bus: process( cpu_rst, cpu_addr, ide_cs )
1264
begin
1265
  ide_cs0_n    <= not( ide_cs ) or cpu_addr(4);
1266
  ide_cs1_n    <= not( ide_cs and cpu_addr(4));
1267
  ide_dmack_n  <= '1';
1268
  ide_rst_n    <= not cpu_rst;
1269
  ide_con_csel <= '0';
1270
  ide_dasp_n   <= not ide_cs;
1271
 
1272
end process;
1273
 
1274
--
1275
-- Assign CPU interface signals
1276
--
1277
cpu_controls : process( rst_n, pb_hold,
1278
                        acia_irq, kbd_irq, trap_irq, timer_irq )
1279
begin
1280
  cpu_rst  <= not rst_n; -- CPU reset is active high
1281
  cpu_irq  <= acia_irq or kbd_irq;
1282
  cpu_nmi  <= trap_irq;
1283
  cpu_firq <= timer_irq;
1284
  cpu_halt <= '0';
1285
  cpu_hold <= pb_hold;
1286
end process;
1287
 
1288
--
1289
-- Assign DPR bus interface signals
1290
--
1291
my_dpr_bus : process( bus_cs_n, bus_rw, cpu_rw )
1292
begin
1293
  bus_cs <= not bus_cs_n;
1294
  bus_wr <= not bus_rw;
1295
  dpr_wr <= not cpu_rw;
1296
--  trace_data_out <= (others=>'0');
1297
end process;
1298
 
1299
--
1300
-- Assign VDU VGA output signals
1301
-- only 8 colours are handled.
1302
--
1303
my_vga_out: process( vga_red_o, vga_green_o, vga_blue_o )
1304
begin
1305
  vga_red(0)   <= vga_red_o;
1306
  vga_red(1)   <= vga_red_o;
1307
  vga_green(0) <= vga_green_o;
1308
  vga_green(1) <= vga_green_o;
1309
  vga_blue(0)  <= vga_blue_o;
1310
  vga_blue(1)  <= vga_blue_o;
1311
end process;
1312
 
1313
end rtl; --===================== End of architecture =======================--

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