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Define fifos: msg_tx_fifo, msg_rx_fifo
[z180-stamp.git] / avr / z80-if.c
1 /**
2 *
3 * Pin assignments
4 *
5 * | Z180-Sig | AVR-Port | Dir | Special Function |
6 * +------------+---------------+-------+-----------------------+
7 * | A0 | PA 0 | O | |
8 * | A1 | PA 1 | O | |
9 * | A2 | PA 2 | O | |
10 * | A3 | PA 3 | O | |
11 * | A4 | PA 4 | O | |
12 * | A5 | PA 5 | O | |
13 * | A6 | PA 6 | O | |
14 * | A7 | PA 7 | O | |
15 * | A8 | PC 0 | O | |
16 * | A9 | PC 1 | O | |
17 * | A10 | PC 2 | O | |
18 * | A11 | PC 3 | O | |
19 * | A12 | PC 4 | O | |
20 * | A13 | PC 5 | O | |
21 * | A14 | PC 6 | O | |
22 * | A15 | PC 7 | O | |
23 * | A16 | PE 2 | O | |
24 * | A17 | PE 3 | O | |
25 * | A18 | PE 4 | O | |
26 * | D0 | PF 0 | I/O | |
27 * | D1 | PF 1 | I/O | |
28 * | D2 | PF 2 | I/O | |
29 * | D3 | PF 3 | I/O | |
30 * | D4 | PF 4 | I/O | |
31 * | D5 | PF 5 | I/O | |
32 * | D6 | PF 6 | I/O | |
33 * | D7 | PF 7 | I/O | |
34 * | RD | PD 3 | O | |
35 * | WR | PD 2 | O | |
36 * | MREQ | PD 4 | O | |
37 * | RST | PD 5 | O | |
38 * | BUSREQ | PD 7 | O | |
39 * | BUSACK | PD 6 | I | |
40 * | IOCS1 | PE 5 | I | |
41 * |* HALT | P | | |
42 * |* NMI | P | | |
43 * | | P | | |
44 * | | P | | af1 USART1_TX |
45 * | | P | | af1 USART1_RX |
46 * | | P |JTDI | remap SPI1_NSS' |
47 * | | P |JTDO | remap SPI1_SCK' |
48 * | | P |JTRST | remap SPI1_MISO' |
49 * | | P | | remap SPI1_MOSI' |
50 * | | P | | af1 OSC32 |
51 * | | P | | af1 OSC32 |
52
53
54 */
55
56 #include <avr/io.h>
57 #include <util/delay.h>
58 #include <util/atomic.h>
59 #include <stdio.h>
60 #include "debug.h"
61 #include "z80-if.h"
62
63
64 /* Number of array elements */
65 #define NELEMS(x) (sizeof x/sizeof *x)
66
67 struct bits {
68 uint8_t b0:1;
69 uint8_t b1:1;
70 uint8_t b2:1;
71 uint8_t b3:1;
72 uint8_t b4:1;
73 uint8_t b5:1;
74 uint8_t b6:1;
75 uint8_t b7:1;
76 } __attribute__((__packed__));
77
78 typedef struct bits pbit_t;
79
80 #define SBIT(port,pin) ((*(volatile struct bits*)&port).b##pin)
81
82
83 //#define P_ZCLK PORTB
84 //#define ZCLK 5
85 //#define DDR_ZCLK DDRB
86 #define P_MREQ PORTD
87 #define MREQ 4
88 #define DDR_MREQ DDRD
89 #define P_RD PORTD
90 #define RD 3
91 #define P_WR PORTD
92 #define WR 2
93 #define P_BUSREQ PORTD
94 #define BUSREQ 7
95 #define DDR_BUSREQ DDRD
96 #define P_BUSACK PORTD
97 #define PIN_BUSACK PIND
98 #define BUSACK 6
99 #define DDR_BUSACK DDRD
100 //#define P_HALT PORTA
101 //#define HALT 12
102 #define P_IOCS1 PORTE
103 #define IOCS1 5
104 #define DDR_IOCS1 DDRE
105 //#define P_NMI PORTB
106 //#define NMI 7
107 #define P_RST PORTD
108 #define DDR_RST DDRD
109 #define RST 5
110
111
112 #define P_DB PORTF
113 #define PIN_DB PINF
114 #define DDR_DB DDRF
115
116 #define P_ADL PORTA
117 #define P_ADH PORTC
118 #define P_ADB PORTE
119 #define PIN_ADB PINE
120 #define DDR_ADL DDRA
121 #define DDR_ADH DDRC
122 #define DDR_ADB DDRE
123
124 #define ADB_WIDTH 3
125 #define ADB_SHIFT 2
126 //#define ADB_PORT PORTE
127
128
129 //#define Z80_O_ZCLK SBIT(P_ZCLK, 5)
130 #define Z80_O_MREQ SBIT(P_MREQ, 4)
131 #define Z80_O_RD SBIT(P_RD, 3)
132 #define Z80_O_WR SBIT(P_WR, 2)
133 #define Z80_O_BUSREQ SBIT(P_BUSREQ, 7)
134 //#define Z80_O_NMI SBIT(P_NMI, )
135 #define Z80_O_RST SBIT(P_RST, 5)
136 #define Z80_I_BUSACK SBIT(PIN_BUSACK, 6)
137 //#define Z80_I_HALT SBIT(P_HALT, )
138
139
140 #define MASK(n) ((1<<(n))-1)
141 #define SMASK(w,s) (MASK(w) << (s))
142
143
144 typedef union {
145 uint32_t l;
146 uint16_t w[2];
147 uint8_t b[4];
148 } addr_t;
149
150
151 static zstate_t zstate;
152
153 /*--------------------------------------------------------------------------*/
154
155
156 static void z80_addrbus_set_tristate(void)
157 {
158 /* /MREQ, /RD, /WR: Input, no pullup */
159 DDR_MREQ &= ~(_BV(MREQ) | _BV(RD) | _BV(WR));
160 Z80_O_MREQ = 0;
161 Z80_O_RD = 0;
162 Z80_O_WR = 0;
163
164 P_ADL = 0;
165 DDR_ADL = 0;
166 P_ADH = 0;
167 DDR_ADH = 0;
168 PIN_ADB = P_ADB & ~(MASK(ADB_WIDTH) << ADB_SHIFT);
169 DDR_ADB = DDR_ADB & ~(MASK(ADB_WIDTH) << ADB_SHIFT);
170 }
171
172
173 static void z80_addrbus_set_active(void)
174 {
175 /* /MREQ, /RD, /WR: Output and high */
176 Z80_O_MREQ = 1;
177 Z80_O_RD = 1;
178 Z80_O_WR = 1;
179 DDR_MREQ |= _BV(MREQ) | _BV(RD) | _BV(WR);
180
181 DDR_ADL = 0xff;
182 DDR_ADH = 0xff;
183 DDR_ADB = DDR_ADB | (MASK(ADB_WIDTH) << ADB_SHIFT);
184 }
185
186
187 static void z80_dbus_set_in(void)
188 {
189 DDR_DB = 0;
190 P_DB = 0;
191 }
192
193
194 static void z80_dbus_set_out(void)
195 {
196 DDR_DB = 0xff;
197 }
198
199
200 static void z80_reset_pulse(void)
201 {
202 Z80_O_RST = 0;
203 _delay_us(10);
204 Z80_O_RST = 1;
205 }
206
207
208 void z80_setup_bus(void)
209 {
210 /* /ZRESET: Output and low */
211 Z80_O_RST = 0;
212 DDR_RST |= _BV(RST);
213
214 /* /BUSREQ: Output and high */
215 Z80_O_BUSREQ = 1;
216 DDR_BUSREQ |= _BV(BUSREQ);
217
218 /* /BUSACK: Input, no pullup */
219 DDR_BUSACK &= ~_BV(BUSACK);
220 P_BUSACK &= ~_BV(BUSACK);
221
222 /* /IOCS1: Input, no pullup */
223 DDR_IOCS1 &= ~_BV(IOCS1);
224 P_IOCS1 &= ~_BV(IOCS1);
225
226 z80_addrbus_set_tristate();
227 z80_dbus_set_in();
228
229 zstate = RESET;
230 }
231
232
233 zstate_t z80_bus_state(void)
234 {
235 return zstate;
236 }
237
238
239 static void z80_busreq_hpulse(void)
240 {
241 z80_dbus_set_in();
242 z80_addrbus_set_tristate();
243
244 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
245 Z80_O_BUSREQ = 1;
246 Z80_O_BUSREQ = 1; /* 2 AVR clock cycles */
247 Z80_O_BUSREQ = 0; /* 2 AVR clock cycles */
248 }
249
250 if (zstate & ZST_ACQUIRED) {
251 while(Z80_I_BUSACK == 1)
252 ;
253 z80_addrbus_set_active();
254 }
255 }
256
257
258 /*
259
260 + | | | | |
261 + State | RESET | RESET_AQRD | RUNNING | RUNNING_AQRD |
262 + | | | | |
263 + | 0 | 1 | 2 | 3 |
264 Event + | | | | |
265 ----------------+---------------+---------------+---------------+---------------+
266 | | | | |
267 Reset | 0 | 0 | 0 | 0 |
268 | | | | |
269 | | | | |
270 Request | 1 | | 3 | |
271 | | | | |
272 | | | | |
273 Release | | 0 | | 2 |
274 | | | | |
275 | | | | |
276 Run | 2 | 3 | | |
277 | | | | |
278 | | | | |
279 Restart | | | 2 | 3 |
280 | | | | |
281 | | | | |
282 M_Cycle | | | | 3 |
283 | | | | |
284 | | | | |
285 */
286
287 zstate_t z80_bus_cmd(bus_cmd_t cmd)
288 {
289 switch (cmd) {
290
291 case Reset:
292 z80_dbus_set_in();
293 z80_addrbus_set_tristate();
294 Z80_O_RST = 0;
295 Z80_O_BUSREQ = 1;
296 zstate = RESET;
297 break;
298
299 case Request:
300 switch (zstate) {
301 case RESET:
302 Z80_O_BUSREQ = 0;
303 Z80_O_RST = 1;
304 while(Z80_I_BUSACK == 1)
305 ;
306 z80_addrbus_set_active();
307 zstate = RESET_AQRD;
308 break;
309
310 case RUNNING:
311 Z80_O_BUSREQ = 0;
312 while(Z80_I_BUSACK == 1)
313 ;
314 z80_addrbus_set_active();
315 zstate = RUNNING_AQRD;
316 break;
317
318 default:
319 break;
320 }
321 break;
322
323 case Release:
324 switch (zstate) {
325 case RESET_AQRD:
326 z80_dbus_set_in();
327 z80_addrbus_set_tristate();
328 Z80_O_RST = 0;
329 Z80_O_BUSREQ = 1;
330 zstate = RESET;
331 break;
332 case RUNNING_AQRD:
333 z80_dbus_set_in();
334 z80_addrbus_set_tristate();
335 Z80_O_BUSREQ = 1;
336 zstate = RUNNING;
337 break;
338 default:
339 break;
340 }
341 break;
342
343 case Run:
344 switch (zstate) {
345 case RESET:
346 Z80_O_RST = 1;
347 zstate = RUNNING;
348 break;
349
350 case RESET_AQRD:
351 z80_dbus_set_in();
352 z80_addrbus_set_tristate();
353 z80_reset_pulse();
354 z80_addrbus_set_active();
355 zstate = RUNNING_AQRD;
356 break;
357 default:
358 break;
359 }
360 break;
361
362 case Restart:
363 switch (zstate) {
364 case RUNNING:
365 case RUNNING_AQRD:
366 z80_reset_pulse();
367 break;
368 default:
369 break;
370 }
371 break;
372
373 case M_Cycle:
374 switch (zstate) {
375 case RUNNING_AQRD:
376 z80_busreq_hpulse();
377 break;
378 default:
379 break;
380 }
381 }
382 return zstate;
383 }
384
385
386 /*--------------------------------------------------------------------------*/
387
388 static
389 //inline __attribute__ ((always_inline))
390 void z80_setaddress(uint32_t addr)
391 {
392 addr_t x; x.l = addr;
393
394 P_ADL = x.b[0];
395 P_ADH = x.b[1];
396 PIN_ADB = ((x.b[2] << ADB_SHIFT) ^ P_ADB) & MASK(ADB_WIDTH) << ADB_SHIFT ;
397 }
398
399 void z80_write(uint32_t addr, uint8_t data)
400 {
401 z80_setaddress(addr);
402 Z80_O_MREQ = 0;
403 z80_dbus_set_out();
404 P_DB = data;
405 P_DB = data;
406 Z80_O_WR = 0;
407 Z80_O_WR = 0;
408 Z80_O_WR = 1;
409 Z80_O_MREQ = 1;
410 }
411
412 uint8_t z80_read(uint32_t addr)
413 {
414 uint8_t data;
415
416 z80_setaddress(addr);
417 Z80_O_MREQ = 0;
418 z80_dbus_set_in();
419 Z80_O_RD = 0;
420 Z80_O_RD = 0;
421 Z80_O_RD = 0;
422 data = PIN_DB;
423 Z80_O_RD = 1;
424 Z80_O_MREQ = 1;
425
426 return data;
427 }
428
429
430 void z80_memset(uint32_t addr, uint8_t data, uint32_t length)
431 {
432 z80_dbus_set_out();
433 Z80_O_MREQ = 0;
434 while(length--) {
435 z80_setaddress(addr++);
436 P_DB = data;
437 P_DB = data;
438 Z80_O_WR = 0;
439 Z80_O_WR = 0;
440 Z80_O_WR = 1;
441 }
442 Z80_O_MREQ = 1;
443 }
444
445 void z80_write_block(const __flash uint8_t *src, uint32_t dest, uint32_t length)
446 {
447 uint8_t data;
448
449 z80_dbus_set_out();
450 Z80_O_MREQ = 0;
451 while(length--) {
452 z80_setaddress(dest++);
453 data = *src++;
454 P_DB = data;
455 P_DB = data;
456 Z80_O_WR = 0;
457 Z80_O_WR = 0;
458 Z80_O_WR = 1;
459 }
460 Z80_O_MREQ = 1;
461 }
462
463 /*
464 0179' rx.bs_mask: ds 1 ; (buf_len - 1)
465 017A' rx.in_idx: ds 1 ;
466 017B' rx.out_idx: ds 1 ;
467 017C' rx.buf: ds rx.buf_len ;
468 018B' rx.buf_end equ $-1 ; last byte (start+len-1)
469
470 018C' tx.bs_mask: ds 1 ; (buf_len - 1)
471 018D' tx.in_idx: ds 1 ;
472 018E' tx.out_idx: ds 1 ;
473 018F' tx.buf: ds tx.buf_len ;
474 019E' tx.buf_end equ $-1 ; last byte
475 */
476
477
478 typedef struct __attribute__((packed)) {
479 uint8_t mask;
480 uint8_t in_idx;
481 uint8_t out_idx;
482 uint8_t buf[];
483 } zfifo_t;
484
485
486
487 #define FIFO_BUFSIZE_MASK -3
488 #define FIFO_INDEX_IN -2
489 #define FIFO_INDEX_OUT -1
490
491
492 static struct {
493 uint32_t base;
494 uint8_t idx_out,
495 idx_in,
496 mask;
497 } fifo_dsc[NUM_FIFOS];
498
499
500 void z80_memfifo_init(const fifo_t f, uint32_t adr)
501 {
502
503 DBG_P(2, "z80_memfifo_init: %i, %lx\n", f, adr);
504
505 fifo_dsc[f].base = adr;
506
507 z80_bus_cmd(Request);
508
509 fifo_dsc[f].mask = z80_read(adr + FIFO_BUFSIZE_MASK);
510 fifo_dsc[f].idx_in = z80_read(adr + FIFO_INDEX_IN);
511 fifo_dsc[f].idx_out = z80_read(adr + FIFO_INDEX_OUT);
512
513 z80_bus_cmd(Release);
514 }
515
516
517 int z80_memfifo_is_empty(const fifo_t f)
518 {
519 int rc = 1;
520
521 if (((Stat & S_MSG_PENDING) || f != fifo_in) && fifo_dsc[f].base != 0)
522 {
523
524 uint32_t adr = fifo_dsc[f].base + FIFO_INDEX_IN;
525 uint8_t idx;
526
527 z80_bus_cmd(Request);
528 idx = z80_read(adr);
529 z80_bus_cmd(Release);
530 rc = idx == fifo_dsc[f].idx_out;
531 }
532
533 return rc;
534 }
535
536 int z80_memfifo_is_full(const fifo_t f)
537 {
538 int rc = 1;
539
540 if (fifo_dsc[f].base != 0) {
541 z80_bus_cmd(Request);
542 rc = ((fifo_dsc[f].idx_in + 1) & fifo_dsc[f].mask)
543 == z80_read(fifo_dsc[f].base+FIFO_INDEX_OUT);
544 z80_bus_cmd(Release);
545 }
546 return rc;
547 }
548
549 uint8_t z80_memfifo_getc(const fifo_t f)
550 {
551 uint8_t rc, idx;
552
553 while (z80_memfifo_is_empty(f))
554 ;
555
556 z80_bus_cmd(Request);
557 idx = fifo_dsc[f].idx_out;
558 rc = z80_read(fifo_dsc[f].base+idx);
559 fifo_dsc[f].idx_out = ++idx & fifo_dsc[f].mask;
560 z80_write(fifo_dsc[f].base+FIFO_INDEX_OUT, fifo_dsc[f].idx_out);
561 z80_bus_cmd(Release);
562
563 return rc;
564 }
565
566
567 void z80_memfifo_putc(fifo_t f, uint8_t val)
568 {
569 int idx;
570
571 while (z80_memfifo_is_full(f))
572 ;
573
574 z80_bus_cmd(Request);
575 idx = fifo_dsc[f].idx_in;
576 z80_write(fifo_dsc[f].base+idx, val);
577 fifo_dsc[f].idx_in = ++idx & fifo_dsc[f].mask;
578 z80_write(fifo_dsc[f].base+FIFO_INDEX_IN, fifo_dsc[f].idx_in);
579 z80_bus_cmd(Release);
580 }
Z180 Stamp Monitor