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226d3221 L |
1 | /* |
2 | * (C) Copyright 2018 Leo C. <erbl259-lmu@yahoo.de> | |
3 | * | |
4 | * SPDX-License-Identifier: GPL-2.0 | |
5 | */ | |
6 | ||
7 | #include "cmd_cpu.h" | |
8 | //#include <ctype.h> | |
dbc1de70 | 9 | #include <util/atomic.h> |
226d3221 L |
10 | |
11 | #include "z80-if.h" | |
12 | #include "con-utils.h" | |
13 | //#include "env.h" | |
51dd0948 L |
14 | #include "eval_arg.h" |
15 | #include "timer.h" | |
16 | #include "getopt-min.h" | |
226d3221 L |
17 | //#include "debug.h" |
18 | ||
19 | /* hack to get Z180 loadfile into flash memory */ | |
20 | #define const const FLASH | |
21 | #include "../z180/cpuinfo.h" | |
22 | #undef const | |
23 | ||
24 | ||
dbc1de70 L |
25 | /* |
26 | * delay for <count> ms... | |
27 | */ | |
28 | static void test_delay(uint32_t count) | |
29 | { | |
30 | uint32_t ts = get_timer(0); | |
31 | ||
32 | while (get_timer(ts) <= count); | |
33 | } | |
34 | ||
35 | static int32_t z80_measure_phi(uint8_t cycles, bool input_clk, uint16_t wait_ms) | |
36 | { | |
37 | uint16_t ref_stop; | |
38 | uint16_t ref_ovfl; | |
39 | uint32_t x_freq; | |
40 | ||
41 | ||
42 | PRR1 &= ~_BV(PRTIM3); | |
43 | TCCR3A = 0; | |
44 | TCCR3B = 0b000<<CS30; /* stop counter */ | |
45 | TCNT3 = 0; | |
46 | TIFR3 = _BV(TOV3); | |
47 | ref_ovfl = 0; | |
48 | ATOMIC_BLOCK(ATOMIC_FORCEON) { | |
49 | /* Reset pending int */ | |
50 | EIFR = _BV(INTF6); | |
51 | /* Wait for falling edge */ | |
52 | while ((EIFR & _BV(INTF6)) == 0) | |
53 | ; | |
54 | //ref_start = TCNT4; | |
55 | OCR4B = TCNT4; | |
56 | TCCR3B = 0b110<<CS30; /* Count falling edges on T3 (==INT6) */ | |
57 | TIFR4 = _BV(OCF4B); /* clear compare match flag */ | |
58 | } | |
59 | while (ref_ovfl < 60) { | |
60 | ATOMIC_BLOCK(ATOMIC_FORCEON) { | |
61 | if ((TIFR4 & _BV(OCF4B)) != 0) { | |
62 | TIFR4 = _BV(OCF4B); | |
63 | ref_ovfl++; | |
64 | } | |
65 | } | |
66 | } | |
67 | ||
68 | ATOMIC_BLOCK(ATOMIC_FORCEON) { | |
69 | EIFR = _BV(INTF6); | |
70 | for (;;) { | |
71 | if (EIFR & _BV(INTF6)) | |
72 | break; | |
73 | if (TIFR4 & _BV(OCF4B)) { | |
74 | if (EIFR & _BV(INTF6)) | |
75 | break; | |
76 | TIFR4 = _BV(OCF4B); | |
77 | if (EIFR & _BV(INTF6)) | |
78 | break; | |
79 | ref_ovfl++; | |
80 | if (EIFR & _BV(INTF6)) | |
81 | break; | |
82 | if (ref_ovfl == 0) | |
83 | break; | |
84 | } | |
85 | } | |
86 | ref_stop = TCNT4; | |
87 | TCCR3B = 0b000<<CS30; /* stop counter */ | |
88 | if ((TIFR4 & _BV(OCF4B)) != 0) { | |
89 | TIFR4 = _BV(OCF4B); | |
90 | if (ref_ovfl) | |
91 | ref_ovfl++; | |
92 | } | |
93 | } | |
94 | ||
95 | if (ref_ovfl == 0) | |
96 | x_freq = 0xFFFFFFFE; | |
97 | else | |
98 | { | |
99 | uint32_t ref_cnt = (ref_stop - OCR4B) + ((uint32_t)ref_ovfl << 16); | |
100 | ||
101 | x_freq = TCNT3; /* x_cnt (17 bit) */ | |
102 | if ((TIFR3 & _BV(TOV3)) != 0) | |
103 | x_freq += 1UL << 16; | |
104 | uint32_t x_cnt = x_freq; | |
105 | if (input_clk) /* compute input clock */ | |
106 | x_freq *= 2; | |
107 | x_freq *= cycles; | |
108 | ||
109 | x_freq = ((uint64_t) x_freq * F_CPU + (ref_cnt / 2))/ ref_cnt; | |
110 | ||
111 | printf_P(PSTR("ref_start: %6u, ref_stop: %6u, ref_ovfl: %4u, ref_cnt: %9lu\n" | |
112 | " TCNT3: %6u, x_cnt: %6lu, cycles: %3u, xfreq: %9lu\n"), | |
113 | OCR4B, ref_stop, ref_ovfl, ref_cnt, | |
114 | TCNT3, x_cnt, cycles, x_freq); | |
115 | ||
116 | /* round to 5 decimal digits */ | |
117 | uint8_t sc = 0; | |
118 | while (x_freq >= 100000UL) { | |
119 | x_freq = (x_freq + 5)/10; | |
120 | ++sc; | |
121 | } | |
122 | while (sc--) | |
123 | x_freq *= 10; | |
124 | } | |
125 | ||
126 | /* Stop Timer */ | |
127 | TCCR3B = 0; | |
128 | PRR1 |= _BV(PRTIM3); | |
129 | ||
130 | return (int32_t) x_freq; | |
131 | } | |
132 | ||
133 | ||
226d3221 L |
134 | static const FLASH char * const FLASH cpu_strings[] = { |
135 | FSTR("Unknown CPU"), | |
136 | FSTR("8080"), | |
137 | FSTR("8085"), | |
138 | FSTR("Z80"), | |
139 | FSTR("x180"), | |
140 | FSTR("HD64180"), | |
141 | FSTR("Z80180"), | |
142 | FSTR("Z80S180"), | |
143 | }; | |
144 | ||
145 | command_ret_t do_cpuchk(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc UNUSED, char * const argv[] UNUSED) | |
146 | { | |
147 | uint8_t done = 0; | |
148 | uint8_t cputype; | |
149 | ERRNUM err = ESUCCESS; | |
150 | uint8_t ram_save[cpuinfo_length]; | |
151 | ||
152 | if (z80_bus_state() & ZST_RUNNING) { | |
153 | err = ERUNNING; | |
154 | } else { | |
155 | z80_bus_request_or_exit(); | |
156 | z80_read_block(ram_save, 0, cpuinfo_length); | |
157 | z80_load_mem(0, cpuinfo, | |
158 | &cpuinfo_sections, | |
159 | cpuinfo_address, | |
160 | cpuinfo_length_of_sections); | |
161 | z80_bus_cmd(Release); | |
162 | ||
163 | if (argv[1] && (argv[1][0] == 'n')) | |
164 | goto donot; | |
165 | ||
166 | z80_bus_cmd(Run); | |
167 | ||
168 | clear_ctrlc(); /* forget any previous Control C */ | |
169 | while (done != 0xFF) { | |
170 | _delay_ms(8); | |
171 | /* check for ctrl-c to abort... */ | |
172 | if (had_ctrlc() || ctrlc()) { | |
173 | err = EINTR; | |
174 | break; | |
175 | } | |
176 | z80_bus_cmd(Request); | |
177 | done = z80_read(3); | |
178 | if (done == 0xFF) | |
179 | cputype = z80_read(4); | |
180 | z80_bus_cmd(Release); | |
181 | } | |
182 | z80_bus_cmd(Reset); | |
183 | z80_bus_cmd(Request); | |
184 | // z80_write_block(ram_save, 0, cpuinfo_length); | |
185 | z80_bus_cmd(Release); | |
186 | } | |
187 | ||
188 | donot: | |
189 | ||
190 | if (err) | |
191 | cmd_error(CMD_RET_FAILURE, err, NULL); | |
192 | ||
193 | if (done == 0xFF) { | |
194 | if (cputype >= ARRAY_SIZE(cpu_strings)) | |
195 | cputype = 0; | |
196 | printf_P(PSTR("Detected CPU: %S\n"), cpu_strings[cputype]); | |
197 | } | |
198 | ||
199 | return CMD_RET_SUCCESS; | |
200 | } | |
51dd0948 | 201 | |
51dd0948 L |
202 | command_ret_t do_cpu_test(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc, char * const argv[]) |
203 | { | |
204 | ||
205 | uint32_t pulsewidth = 10; /* ms */ | |
206 | ||
51dd0948 L |
207 | int opt; |
208 | while ((opt = getopt(argc, argv, PSTR("t:"))) != -1) { | |
209 | switch (opt) { | |
210 | case 't': | |
211 | pulsewidth = eval_arg(optarg, NULL); | |
212 | break; | |
213 | default: /* '?' */ | |
214 | return CMD_RET_USAGE; | |
215 | } | |
216 | } | |
217 | ||
218 | if ((z80_bus_state() & ZST_ACQUIRED) != RESET) | |
219 | cmd_error(CMD_RET_FAILURE, ERUNNING, NULL); | |
220 | ||
221 | clear_ctrlc(); /* forget any previous Control C */ | |
222 | do { | |
223 | z80_bus_cmd(Request); | |
224 | test_delay(pulsewidth); | |
225 | z80_bus_cmd(Release); | |
226 | test_delay(pulsewidth); | |
227 | } while (!(had_ctrlc() || ctrlc())); | |
228 | ||
229 | return CMD_RET_SUCCESS; | |
230 | } | |
231 | ||
dbc1de70 L |
232 | command_ret_t do_bus_test(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc UNUSED, char * const argv[] UNUSED) |
233 | { | |
234 | char ch; | |
235 | ||
236 | #if 0 | |
dbc1de70 L |
237 | int opt; |
238 | while ((opt = getopt(argc, argv, PSTR("t:"))) != -1) { | |
239 | switch (opt) { | |
240 | case 't': | |
241 | pulsewidth = eval_arg(optarg, NULL); | |
242 | break; | |
243 | default: /* '?' */ | |
244 | return CMD_RET_USAGE; | |
245 | } | |
246 | } | |
247 | #endif | |
248 | ||
249 | my_puts_P(PSTR( | |
250 | " 1: RESET 4: RUN r: Toggle /RESET\n" | |
251 | " 2: REQUEST 5: RESTART b: Toggle /BUSREQ\n" | |
252 | " 3: RELEASE 6: M_CYCLE\n" | |
253 | "\n" | |
254 | //"Bus state: " | |
255 | )); | |
256 | ||
257 | do { | |
258 | ch = my_getchar(1); | |
259 | if (ch >= 0) { | |
260 | switch (ch) { | |
261 | case '1': /* bus_cmd RESET */ | |
262 | case '2': /* bus_cmd REQUEST */ | |
263 | case '3': /* bus_cmd RELEASE */ | |
264 | case '4': /* bus_cmd RUN */ | |
265 | case '5': /* bus_cmd RESTART */ | |
266 | case '6': /* bus_cmd M_CYCLE */ | |
267 | z80_bus_cmd(ch - '1' + Reset); | |
268 | break; | |
269 | case 'r': /* Toggle RESET */ | |
270 | z80_toggle_reset(); | |
271 | break; | |
272 | case 'b': /* Toggle BUSREQ */ | |
273 | z80_toggle_busreq(); | |
274 | break; | |
275 | } | |
276 | test_delay(10); | |
277 | uint32_t cycles = z80_get_busreq_cycles(); | |
278 | printf_P(PSTR("\rState: %.2x, cycles: %lu, time: %luus "), | |
279 | z80_bus_state(), cycles, (uint32_t) (cycles * 1000000LL / F_CPU)); | |
280 | } | |
281 | } while (ch != 0x03); | |
282 | ||
283 | putchar('\n'); | |
284 | return CMD_RET_SUCCESS; | |
285 | } | |
286 | ||
d66348b4 L |
287 | command_ret_t do_busack_test(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc UNUSED, char * const argv[] UNUSED) |
288 | { | |
289 | ||
290 | if ((z80_bus_state() & ZST_ACQUIRED) != RESET) | |
291 | cmd_error(CMD_RET_FAILURE, ERUNNING, NULL); | |
292 | ||
293 | z80_bus_cmd(Request); | |
294 | uint32_t result = z80_get_busreq_cycles(); | |
295 | test_delay(20); | |
296 | z80_bus_cmd(Release); | |
297 | ||
298 | #if 0 | |
299 | long div; | |
300 | ||
301 | pinconf = gpio_config_get(pin); | |
302 | if (pinconf == OUTPUT_TIMER) { | |
303 | div = gpio_clockdiv_get(pin); | |
dbc1de70 | 304 | } |
d66348b4 L |
305 | #endif |
306 | ||
307 | ||
308 | printf_P(PSTR("cycles: %lu, time: %luus\n"), result, (uint32_t) (result * 1000000LL / F_CPU)); | |
309 | ||
310 | return CMD_RET_SUCCESS; | |
311 | } | |
312 | ||
dbc1de70 | 313 | command_ret_t do_cpu_freq(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc, char * const argv[]) |
51dd0948 | 314 | { |
dbc1de70 L |
315 | |
316 | #define O_SILENT (1<<0) | |
317 | #define O_WENV (1<<1) | |
318 | #define O_LOAD_LOOP (1<<2) | |
319 | #define O_UNLOAD_LOOP (1<<3) | |
320 | ||
321 | uint_fast8_t options = O_LOAD_LOOP | O_UNLOAD_LOOP; | |
51dd0948 L |
322 | uint8_t lcycles = 18; |
323 | uint16_t timeout = 1000; | |
324 | ||
325 | uint8_t eicrb_save; | |
326 | uint8_t eimsk_save; | |
327 | uint8_t mem_save[cpuinfo_length]; | |
328 | ||
51dd0948 | 329 | int opt; |
dbc1de70 | 330 | while ((opt = getopt(argc, argv, PSTR("swnuc:t:"))) != -1) { |
51dd0948 L |
331 | switch (opt) { |
332 | case 's': | |
dbc1de70 | 333 | options |= O_SILENT; |
51dd0948 L |
334 | break; |
335 | case 'w': | |
dbc1de70 | 336 | options |= O_WENV; |
51dd0948 L |
337 | break; |
338 | case 'n': | |
dbc1de70 L |
339 | options &= ~O_LOAD_LOOP; |
340 | break; | |
341 | case 'u': | |
342 | options &= ~O_UNLOAD_LOOP; | |
51dd0948 L |
343 | break; |
344 | case 'c': | |
345 | lcycles = eval_arg(optarg, NULL); | |
346 | break; | |
347 | case 't': | |
dbc1de70 | 348 | timeout = eval_arg(optarg, NULL); |
51dd0948 L |
349 | break; |
350 | default: /* '?' */ | |
351 | return CMD_RET_USAGE; | |
352 | } | |
353 | } | |
dbc1de70 L |
354 | if (argc - optind != 0) |
355 | return CMD_RET_USAGE; | |
51dd0948 L |
356 | |
357 | if (z80_bus_state() & ZST_RUNNING) { | |
dbc1de70 | 358 | if (!(options & O_SILENT)) |
51dd0948 L |
359 | printf_P(PSTR("Frequency measuring failed. CPU allready running!\n")); |
360 | return CMD_RET_FAILURE; | |
361 | } | |
362 | ||
363 | ATOMIC_BLOCK(ATOMIC_FORCEON) { | |
364 | /* Save state and disable INT6 */ | |
365 | eimsk_save = EIMSK; | |
366 | EIMSK &= ~_BV(INT6); | |
367 | /* Save state and set INT6 for falling edge */ | |
368 | eicrb_save = EICRB; | |
369 | EICRB = (eicrb_save & ~(0b11 << ISC60)) | (0b10 << ISC60); | |
370 | } | |
371 | ||
372 | z80_bus_cmd(Request); | |
dbc1de70 | 373 | if (options & O_LOAD_LOOP) { |
51dd0948 L |
374 | z80_read_block(mem_save, 0, cpuinfo_length); |
375 | z80_load_mem(0, cpuinfo, | |
376 | &cpuinfo_sections, | |
377 | cpuinfo_address, | |
378 | cpuinfo_length_of_sections); | |
379 | } | |
dbc1de70 | 380 | Stat &= ~S_IO_0X40; /* Reset pending int */ |
51dd0948 | 381 | z80_bus_cmd(Release); |
dbc1de70 | 382 | z80_bus_cmd(Run); |
51dd0948 | 383 | |
dbc1de70 L |
384 | clear_ctrlc(); /* forget any previous Control C */ |
385 | ERRNUM err = 0; | |
386 | ||
387 | /* Wait for falling edge */ | |
388 | do { | |
389 | /* check for ctrl-c to abort... */ | |
390 | if (had_ctrlc() || ctrlc()) { | |
391 | err = EINTR; | |
392 | break; | |
393 | } | |
394 | } while ((Stat & S_IO_0X40) == 0); | |
395 | ||
396 | int32_t cpu_freq; | |
397 | if (!err) | |
398 | cpu_freq = z80_measure_phi(lcycles, false, timeout); | |
51dd0948 L |
399 | |
400 | z80_bus_cmd(Reset); | |
dbc1de70 L |
401 | if (options & O_UNLOAD_LOOP) { |
402 | z80_bus_cmd(Request); | |
51dd0948 | 403 | z80_write_block(mem_save, 0, cpuinfo_length); |
dbc1de70 L |
404 | z80_bus_cmd(Release); |
405 | } | |
51dd0948 L |
406 | ATOMIC_BLOCK(ATOMIC_FORCEON) { |
407 | /* Restore INT6 */ | |
408 | eicrb_save = EICRB; | |
409 | EICRB = (EICRB & ~(0b11 << ISC60)) | (eicrb_save & (0b11 << ISC60)); | |
410 | if ((eimsk_save & _BV(INT6)) != 0) | |
411 | EIMSK |= _BV(INT6); | |
412 | /* Reset pending int */ | |
413 | EIFR = _BV(INTF6); | |
414 | } | |
415 | ||
dbc1de70 L |
416 | if (err) |
417 | cmd_error(CMD_RET_FAILURE, err, NULL); | |
51dd0948 | 418 | |
dbc1de70 L |
419 | if (!(options & O_SILENT)) { |
420 | printf_P(PSTR("%ld%S\n"), cpu_freq, cpu_freq < 0 ? PSTR("") : PSTR("Hz")); | |
421 | // if (cpu_freq != 0) | |
422 | // else | |
423 | // printf_P(PSTR("No CPU clock or input frequency to low!\n")); | |
424 | } | |
425 | #if 0 | |
426 | if (options & O_WENV) { | |
51dd0948 | 427 | if (setenv_ulong(PSTR(ENV_CPU_FREQ), cpu_freq)) { |
dbc1de70 | 428 | if (!(options & O_SILENT)) |
51dd0948 L |
429 | printf_P(PSTR("'SETENV (%S, %lu)' failed!\n"), PSTR(ENV_CPU_FREQ), cpu_freq); |
430 | return CMD_RET_FAILURE; | |
431 | } | |
432 | } | |
dbc1de70 | 433 | #endif |
51dd0948 L |
434 | return CMD_RET_SUCCESS; |
435 | } | |
dbc1de70 | 436 | |
51dd0948 L |
437 | |
438 | /* | |
439 | * command table for fat subcommands | |
440 | */ | |
441 | ||
442 | cmd_tbl_t cmd_tbl_cpu[] = { | |
443 | CMD_TBL_ITEM( | |
444 | chkcpu, CONFIG_SYS_MAXARGS, CTBL_RPT, do_cpuchk, | |
445 | "Check CPU", | |
446 | "" | |
447 | ), | |
dbc1de70 L |
448 | CMD_TBL_ITEM( |
449 | buscmd, CONFIG_SYS_MAXARGS, CTBL_RPT, do_bus_test, | |
450 | "Bus commands", | |
451 | "" | |
452 | ), | |
51dd0948 L |
453 | CMD_TBL_ITEM( |
454 | test, CONFIG_SYS_MAXARGS, 1, do_cpu_test, | |
455 | "Do bus request/release cycles", | |
456 | "[-t pulsewidth]" | |
457 | ), | |
d66348b4 L |
458 | CMD_TBL_ITEM( |
459 | busack, 2, 1, do_busack_test, | |
460 | "Get time from /Reset high to /BUSACK low", | |
461 | "" | |
462 | ), | |
51dd0948 L |
463 | CMD_TBL_ITEM( |
464 | freq, CONFIG_SYS_MAXARGS, 1, do_cpu_freq, | |
465 | "Measure cpu frequency", | |
dbc1de70 L |
466 | "[-qwn] [-c loopcycles] [-t timeout]\n" |
467 | " -q Be quiet\n" | |
468 | // " -w Write result to environment variable '"ENV_CPU_FREQ"'" | |
51dd0948 | 469 | ), |
dbc1de70 | 470 | |
51dd0948 L |
471 | CMD_TBL_ITEM( |
472 | help, CONFIG_SYS_MAXARGS, CTBL_RPT, do_help, | |
473 | "Print sub command description/usage", | |
474 | "\n" | |
475 | " - print brief description of all sub commands\n" | |
476 | "fat help command ...\n" | |
477 | " - print detailed usage of sub cmd 'command'" | |
478 | ), | |
479 | ||
480 | /* This does not use the CMD_TBL_ITEM macro as ? can't be used in symbol names */ | |
481 | {FSTR("?"), CONFIG_SYS_MAXARGS, 1, do_help, | |
482 | NULL, | |
483 | #ifdef CONFIG_SYS_LONGHELP | |
484 | FSTR(""), | |
485 | #endif /* CONFIG_SYS_LONGHELP */ | |
486 | NULL, | |
487 | #ifdef CONFIG_AUTO_COMPLETE | |
488 | NULL, | |
489 | #endif | |
490 | }, | |
491 | /* Mark end of table */ | |
492 | CMD_TBL_END(cmd_tbl_cpu) | |
493 | }; | |
494 | ||
495 | ||
496 | command_ret_t do_cpu(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc UNUSED, char * const argv[] UNUSED) | |
497 | { | |
498 | //puts_P(PSTR("Huch?")); | |
499 | ||
500 | return CMD_RET_USAGE; | |
501 | } | |
502 | ||
503 | ||
dbc1de70 | 504 | #if 0 /* Z180 Single Step Functions */ |
51dd0948 L |
505 | /* |
506 | * Z180 Single Step Functions | |
507 | * | |
508 | */ | |
509 | ||
510 | ||
511 | #define P_RUN PORTG | |
512 | #define RUN 1 | |
513 | #define DDR_RUN DDRG | |
514 | #define P_STEP PORTG | |
515 | #define STEP 0 | |
516 | #define DDR_STEP DDRG | |
517 | #define P_WAIT PORTG | |
518 | #define WAIT 2 | |
519 | #define DDR_WAIT DDRG | |
520 | /* All three signals are on the same Port (PortG) */ | |
521 | #define PORT_SS PORTG | |
522 | #define DDR_SS DDRG | |
523 | #define PIN_SS PING | |
524 | ||
525 | static bool ss_available; | |
526 | ||
527 | int single_step_setup(void) | |
528 | { | |
529 | ss_available = false; | |
530 | ||
531 | #if 0 | |
532 | if (z80_bus_state() & ZST_RUNNING || | |
533 | !(z80_bus_cmd(Request) & ZST_ACQUIRED)) | |
534 | return -1; | |
535 | #endif | |
536 | ||
537 | /* STEP, RUN output, WAIT input */ | |
538 | ||
539 | PORT_SS |= _BV(RUN) | _BV(STEP); | |
540 | DDR_SS |= _BV(RUN) | _BV(STEP); | |
541 | DDR_SS &= ~_BV(WAIT); | |
542 | ||
543 | /* RUN high, MREQ pulse --> WAIT should be low */ | |
544 | z80_mreq_pulse(); | |
545 | ||
546 | if ((PIN_SS & _BV(WAIT)) == 0) { | |
547 | ||
548 | /* RUN high, STEP pulse --> WAIT should be high */ | |
549 | PIN_SS = _BV(STEP); | |
550 | PIN_SS = _BV(STEP); | |
551 | if ((PIN_SS & _BV(WAIT)) != 0) { | |
552 | ||
553 | /* RUN high, MREQ pulse --> WAIT should be low */ | |
554 | z80_mreq_pulse(); | |
555 | if ((PIN_SS & _BV(WAIT)) == 0) { | |
556 | ||
557 | /* RUN low --> WAIT should be high */ | |
558 | PIN_SS = _BV(RUN); | |
559 | if ((PIN_SS & _BV(WAIT)) != 0) { | |
560 | ||
561 | /* RUN low, STEP pulse --> WAIT should be high */ | |
562 | PIN_SS = _BV(STEP); | |
563 | PIN_SS = _BV(STEP); | |
564 | if ((PIN_SS & _BV(WAIT)) != 0) { | |
565 | ||
566 | /* all tests passed */ | |
567 | ss_available = true; | |
568 | } | |
569 | } | |
570 | } | |
571 | } | |
572 | } | |
573 | ||
574 | if (!ss_available) { | |
575 | DDR_SS &= ~(_BV(STEP) | _BV(RUN)); | |
576 | PORT_SS |= _BV(RUN) | _BV(STEP); | |
577 | } | |
578 | ||
579 | return ss_available ? 0 : -1; | |
580 | } | |
581 | #endif |