stm32/z180-stamp-stm32.c

   1 /*
   2  */
   3
   4 #include <stdio.h>
   5
   6 #include <libopencmsis/core_cm3.h>
   7 #include <libopencm3/cm3/nvic.h>
   8 #include <libopencm3/cm3/systick.h>
   9 #include <libopencm3/stm32/rtc.h>
  10 #include <libopencm3/stm32/rcc.h>
  11 #include <libopencm3/stm32/gpio.h>
  12 #include <libopencm3/stm32/timer.h>
  13
  14 #define ODR     0x0c
  15 #define IDR     0x08
  16
  17
  18 #include "debug.h"
  19 #include "serial.h"
  20 #include "z80-if.h"
  21 #include "../z180/hdrom.h"
  22
  23 #define ESCCHAR         ('^'-0x40)
  24
  25 #define S_10MS_TO       (1<<0)
  26
  27 /*
  28  * LED Connections
  29  */
  30
  31 #define LED_PORT        GPIOC
  32 #define LED_BLUE_PIN    GPIO8
  33 #define BLUE            8
  34 #define LED_GREEN_PIN   GPIO9
  35 #define GREEN           9
  36
  37
  38 #define LED_BLUE_ON()     BBIO_PERIPH(LED_PORT+ODR, BLUE) = 1
  39 #define LED_BLUE_OFF()    BBIO_PERIPH(LED_PORT+ODR, BLUE) = 0
  40 #define LED_BLUE_TOGGLE() BBIO_PERIPH(LED_PORT+ODR, BLUE) = !BBIO_PERIPH(LED_PORT+ODR, BLUE)
  41
  42 #define LED_GREEN_ON()     BBIO_PERIPH(LED_PORT+ODR, GREEN) = 1
  43 #define LED_GREEN_OFF()    BBIO_PERIPH(LED_PORT+ODR, GREEN) = 0
  44 #define LED_GREEN_TOGGLE() BBIO_PERIPH(LED_PORT+ODR, GREEN) = !BBIO_PERIPH(LED_PORT+ODR, GREEN)
  45
  46
  47 /*
  48  * Button connections
  49  */
  50
  51 //BBIO_PERIPH(GPIOA+IDR, 0);
  52
  53 #define KEY_PORT        GPIOA_IDR
  54 #define KEY0            GPIO0
  55 //#define KEY1          GPIO1
  56 //#define KEY2          GPIO2
  57
  58 #define REPEAT_MASK     KEY0            // repeat: key0
  59 #define REPEAT_START    100             // after 1s
  60 #define REPEAT_NEXT     20              // every 200ms
  61
  62
  63 typedef enum {
  64         NOTHING, PULSE, BLINK1, BLINK2
  65 } LED_MODE;
  66
  67 typedef struct {
  68         uint8_t mode;
  69         uint8_t ontime, offtime;
  70 } led_stat_t;
  71
  72 volatile uint8_t led_timer[2];
  73 led_stat_t led_stat[2];
  74
  75 volatile int timeout_1s;
  76 volatile uint32_t Stat;
  77
  78
  79 /*--------------------------------------------------------------------------*/
  80
  81
  82 static void clock_setup(void)
  83 {
  84         //rcc_clock_setup_in_hse_8mhz_out_24mhz();
  85         rcc_clock_setup_in_hsi_out_24mhz();
  86
  87         /* Enable clocks for:
  88                 GPIO port A (for GPIO_USART1_TX and Button)
  89                 GPIO port C (LEDs)
  90                 USART1
  91                 TIM16 (RST-Pin)
  92                 TIM1  (IOCS1)
  93         */
  94         rcc_peripheral_enable_clock(&RCC_APB2ENR,
  95                           RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN
  96                         | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_IOPDEN
  97                         | RCC_APB2ENR_USART1EN | RCC_APB2ENR_AFIOEN
  98                         | RCC_APB2ENR_TIM1EN | RCC_APB2ENR_TIM16EN);
  99         /* Enable clocks for:
 100                 TIM3
 101         */
 102         rcc_peripheral_enable_clock(&RCC_APB1ENR,
 103                         RCC_APB1ENR_TIM3EN);
 104
 105         /* Enable clocks for:
 106                 DMA1
 107         */
 108         rcc_peripheral_enable_clock(&RCC_AHBENR,
 109                         RCC_AHBENR_DMA1EN);
 110 }
 111
 112 static void systick_setup(void)
 113 {
 114         /* SysTick interrupt every N clock pulses: set reload to N-1 */
 115         STK_RVR = 24000000/1000 - 1;
 116
 117         /* Set source to core clock, enable int and start counting. */
 118         STK_CSR = STK_CSR_CLKSOURCE_AHB | STK_CSR_TICKINT | STK_CSR_ENABLE;
 119 }
 120
 121 #if 0
 122 static void nvic_setup(void)
 123 {
 124 //      nvic_enable_irq(NVIC_RTC_IRQ);
 125 //      nvic_set_priority(NVIC_RTC_IRQ, 1);
 126 }
 127 #endif
 128
 129 static void tim3_setup(void)
 130 {
 131         TIM3_CR1 = TIM_CR1_CMS_EDGE | TIM_CR1_DIR_UP;
 132
 133         TIM3_CCMR2 = 0
 134                 | TIM_CCMR2_OC4M_FORCE_LOW
 135         /*      | TIM_CCMR2_OC4M_FORCE_HIGH     */
 136         /*      | TIM_CCMR2_OC4M_PWM2           */
 137
 138         /*      | TIM_CCMR2_OC4PE               */
 139         /*      | TIM_CCMR2_OC4FE               */
 140                 | TIM_CCMR2_CC4S_OUT;
 141
 142         TIM3_CCER = TIM_CCER_CC4E
 143                 | TIM_CCER_CC4P;
 144
 145         TIM3_ARR = 48;  /* default */
 146         TIM3_CCR4 = 1;  /*  */
 147 }
 148
 149 static void gpio_setup(void)
 150 {
 151
 152         /* Disable JTAG-DP, but leave SW-DP Enabled. (free PA15, PB3, PB4)
 153            Remap SPI1 to PB3, PB4, PB5 and PA15.
 154            Remap TIM3 (CH1/PC6, CH2/PC7, CH3/PC8, CH4/PC9)
 155            Port D0/Port D1 mapping on OSC_IN/OSC_OUT
 156         */
 157         gpio_primary_remap(AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_ON,
 158                         AFIO_MAPR_SPI1_REMAP
 159                         | AFIO_MAPR_TIM3_REMAP_FULL_REMAP
 160                         | AFIO_MAPR_PD01_REMAP);
 161
 162         /* LEDs and User Button. */
 163         gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ,
 164                       GPIO_CNF_OUTPUT_PUSHPULL, LED_BLUE_PIN);
 165         gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_10_MHZ,
 166                       GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, LED_GREEN_PIN);
 167         gpio_set_mode(GPIOA, GPIO_MODE_INPUT,
 168                       GPIO_CNF_INPUT_FLOAT, GPIO0);
 169 }
 170
 171
 172 /*--------------------------------------------------------------------------*/
 173
 174 void delay_systicks(int ticks)
 175 {
 176         int start, stop, now;
 177
 178         start = STK_CVR;
 179         stop = start - ticks;
 180         if (stop < 0) {
 181                 stop += STK_RVR;
 182                 do {
 183                         now = STK_CVR;
 184                 } while ((now > stop) || (now <= start));
 185         } else {
 186                 do {
 187                         now = STK_CVR;
 188                 } while ((now > stop) && (now <= start));
 189         }
 190 }
 191
 192
 193 /*--------------------------------------------------------------------------*/
 194
 195 static void led_toggle(uint8_t lednr) {
 196         if (lednr == 0)
 197                 LED_BLUE_TOGGLE();
 198         else if (lednr == 1)
 199                 LED_GREEN_TOGGLE();
 200 }
 201
 202 static void led_on(uint8_t lednr) {
 203         if (lednr == 0)
 204                 LED_BLUE_ON();
 205         else if (lednr == 1)
 206                 LED_GREEN_ON();
 207 }
 208
 209 static void led_off(uint8_t lednr) {
 210         if (lednr == 0)
 211                 LED_BLUE_OFF();
 212         else if (lednr == 1)
 213                 LED_GREEN_OFF();
 214 }
 215
 216 static uint8_t led_is_on(uint8_t lednr) {
 217         if (lednr == 0)
 218                 return BBIO_PERIPH(LED_PORT+ODR, BLUE);
 219         else if (lednr == 1)
 220                 return BBIO_PERIPH(LED_PORT+ODR, GREEN);
 221         else
 222                 return 0;
 223 }
 224
 225 static void ledset(uint8_t lednr, uint8_t what, uint8_t len) {
 226
 227         led_stat[lednr].mode = what;
 228         switch (what) {
 229         case PULSE:
 230                 led_stat[lednr].ontime = len;
 231                 led_stat[lednr].offtime = 0;
 232                 led_timer[lednr] = len;
 233                 led_on(lednr);
 234                 break;
 235         case BLINK1:
 236         case BLINK2:
 237                 if (what == BLINK1)
 238                         led_stat[lednr].offtime = 100 - len;
 239                 else
 240                         led_stat[lednr].offtime = 200 - len;
 241                 led_stat[lednr].ontime = len;
 242                 led_timer[lednr] = len;
 243                 led_on(lednr);
 244                 break;
 245         default:
 246                 break;
 247         }
 248 }
 249
 250 /*--------------------------------------------------------------------------*/
 251
 252 static volatile uint16_t key_state,
 253                 key_press, // key press detect
 254                 key_rpt; // key long press and repeat
 255
 256
 257 static uint16_t get_key_press(uint16_t key_mask) {
 258         __disable_irq();
 259         // read and clear atomic !
 260         key_mask &= key_press; // read key(s)
 261         key_press ^= key_mask; // clear key(s)
 262         __enable_irq();
 263         return key_mask;
 264 }
 265
 266 /*
 267 static uint16_t get_key_rpt(uint16_t key_mask) {
 268         __disable_irq();
 269         // read and clear atomic !
 270         key_mask &= key_rpt; // read key(s)
 271         key_rpt ^= key_mask; // clear key(s)
 272         __enable_irq();
 273         return key_mask;
 274 }
 275 */
 276
 277 static uint16_t get_key_short(uint16_t key_mask) {
 278         __disable_irq();
 279         // read key state and key press atomic !
 280         return get_key_press(key_state & key_mask);
 281 }
 282
 283 /*
 284 static uint16_t get_key_long(uint16_t key_mask) {
 285         return get_key_press(get_key_rpt(key_mask));
 286 }
 287 */
 288
 289 static void key_timerproc() {
 290         static uint16_t key_in_last, rpt;
 291         uint16_t key_in, c;
 292
 293         key_in = KEY_PORT;
 294
 295         c = key_in_last & key_in & ~key_state;
 296
 297 //      key_state = key_state  & key_in_last | (key_state  | key_in_last) & key_in;
 298 //      key_state = key_state  & key_in      | (key_state  | key_in)      & key_in_last;
 299
 300         key_state = c | ((key_in_last | key_in) & key_state);
 301
 302 //      key_state = (key_state&key_in_last) | (key_state&key_in) | (key_in_last&key_in);
 303
 304         key_press |= c;
 305
 306         key_in_last = key_in;
 307
 308
 309         if ((key_state & REPEAT_MASK) == 0) // check repeat function
 310                 rpt = REPEAT_START;
 311         if (--rpt == 0) {
 312                 rpt = REPEAT_NEXT; // repeat delay
 313                 key_rpt |= key_state & REPEAT_MASK;
 314         }
 315
 316 }
 317
 318 /*--------------------------------------------------------------------------*/
 319
 320 void sys_tick_handler(void)
 321 {
 322         static int tick_10ms = 0;
 323         static int count_ms = 0;
 324
 325         int i;
 326
 327         ++tick_10ms;
 328         if (tick_10ms == 10)
 329         {
 330                 Stat |= S_10MS_TO;
 331
 332                 tick_10ms = 0;
 333
 334                 i = led_timer[0];
 335                 if (i)
 336                         led_timer[0] = i - 1;
 337                 i = led_timer[1];
 338                 if (i)
 339                         led_timer[1] = i - 1;
 340
 341                 key_timerproc();
 342
 343                 /* Drive timer procedure of low level disk I/O module */
 344                 //disk_timerproc();
 345         }
 346
 347         count_ms++;
 348         if (count_ms == 1000) {
 349                 count_ms = 0;
 350
 351                 i = timeout_1s;
 352                 if (i)
 353                         timeout_1s = i - 1;
 354         }
 355 }
 356
 357 void rtc_isr(void)
 358 {
 359         /* The interrupt flag isn't cleared by hardware, we have to do it. */
 360         rtc_clear_flag(RTC_SEC);
 361
 362 }
 363
 364 /*--------------------------------------------------------------------------*/
 365
 366 void tim3_set(int mode)
 367 {
 368         uint16_t cc_mode;
 369
 370         cc_mode = TIM_CCMR2_CC4S_OUT;
 371
 372         TIM3_CR1 = TIM_CR1_CMS_EDGE | TIM_CR1_DIR_UP /*| TIM_CR1_OPM */ ;
 373
 374         if (mode < 0)
 375                 cc_mode |= TIM_CCMR2_OC4M_FORCE_LOW;
 376         else if (mode == 0)
 377                 cc_mode |= TIM_CCMR2_OC4M_FORCE_HIGH;
 378         else {
 379                 TIM3_ARR = mode;
 380                 TIM3_CCR4 = mode/2;
 381                 cc_mode |= TIM_CCMR2_OC4M_PWM2;
 382         }
 383
 384         TIM3_CCMR2 = cc_mode;
 385
 386         if (mode > 0)
 387                 TIM3_CR1 |= TIM_CR1_CEN;
 388 }
 389
 390 /*--------------------------------------------------------------------------*/
 391
 392 static uint32_t z80_sram_cmp(uint32_t addr, int length, uint8_t wval, int inc)
 393 {
 394         uint8_t rval;
 395         int errors = 0;
 396
 397         DBG_P(1, "SRAM: Check %#.5x byte... ", length);
 398         while (length--) {
 399                 if ((rval = z80_read(addr)) != wval) {
 400                         if (errors == 0) {
 401                                 printf("\nSRAM: Address  W  R\n" \
 402                                        "      -------------\n");
 403 //                                             12345  00 11
 404                         }
 405                         printf("       %.5lx  %.2x %.2x\n", addr, wval, rval);
 406
 407                         if (++errors > 16 )
 408                                 break;
 409                 }
 410                 addr++;
 411                 wval += inc;
 412         }
 413         DBG_P(1, "Done.\n");
 414
 415         return addr;
 416 }
 417
 418 #if 0
 419 static void z80_sram_fill(uint32_t addr, int length, uint8_t startval, int inc)
 420 {
 421         printf("SRAM: Write %#.5x byte... ", length); //fflush(stdout);
 422         while (length--) {
 423                 z80_write(addr, startval);
 424                 ++addr;
 425                 startval += inc;
 426         }
 427         printf("Done.\n");
 428 }
 429
 430
 431 void z80_sram_fill_string(uint32_t addr, int length, const char *text)
 432 {
 433         char c;
 434         const char *p = text;
 435
 436         while (length--) {
 437                 z80_write(addr++, c = *p++);
 438                 if (c == 0)
 439                         p = text;
 440         }
 441 }
 442
 443
 444 uint32_t z80_sram_cmp_string(uint32_t addr, int length, const char *text)
 445 {
 446         char c;
 447         const char *p = text;
 448
 449         while (length--) {
 450                 c = *p++;
 451                 if (z80_read(addr) != c)
 452                         break;
 453                 ++addr;
 454                 if (c == 0)
 455                         p = text;
 456         }
 457         return addr;
 458 }
 459
 460 const char * const qbfox = "Zhe quick brown fox jumps over the lazy dog!";
 461 const char * const qbcat = "Zhe quick brown fox jumps over the lazy cat!";
 462
 463 #endif
 464
 465 uint8_t z80_get_byte(uint32_t adr)
 466 {
 467         uint8_t data;
 468
 469         z80_request_bus();
 470         data = z80_read(adr),
 471         z80_release_bus();
 472
 473         return data;
 474 }
 475
 476
 477 /*--------------------------------------------------------------------------*/
 478
 479 static void do_10ms(void)
 480 {
 481         for (uint_fast8_t i = 0; i < 2; i++) {
 482                 switch (led_stat[i].mode) {
 483                 case PULSE:
 484                         if (led_timer[i] == 0) {
 485                                 led_off(i);
 486                                 led_stat[i].mode = NOTHING;
 487                         }
 488                         break;
 489                 case BLINK1:
 490                 case BLINK2:
 491                         if (led_timer[i] == 0) {
 492                                 if (led_is_on(i))
 493                                         led_timer[i] = led_stat[i].offtime;
 494                                 else
 495                                         led_timer[i] = led_stat[i].ontime;
 496                                 led_toggle(i);
 497                         }
 498                         break;
 499                 default:
 500                         break;
 501                 }
 502         }
 503 }
 504
 505 struct msg_item {
 506         uint8_t fct;
 507         uint8_t sub_min, sub_max;
 508         void (*func)(uint8_t, int, uint8_t *);
 509 };
 510
 511 uint32_t msg_to_addr(uint8_t *msg)
 512 {
 513         uint32_t addr = msg[0] + (msg[1] << 8) + (msg[2] << 16);
 514
 515         return addr;
 516
 517 }
 518
 519 void do_msg_ini_msgfifo(uint8_t subf, int len, uint8_t * msg)
 520 {
 521         (void)subf; (void)len;
 522
 523         z80_init_msg_fifo(msg_to_addr(msg));
 524 }
 525
 526
 527 void do_msg_ini_memfifo(uint8_t subf, int len, uint8_t * msg)
 528 {
 529         (void)len;
 530
 531         z80_memfifo_init(subf - 1, msg_to_addr(msg));
 532 }
 533
 534
 535 void do_msg_char_out(uint8_t subf, int len, uint8_t * msg)
 536 {
 537         (void)subf;
 538
 539         while (len--)
 540                 putchar(*msg++);
 541 }
 542
 543
 544 const struct msg_item z80_messages[] =
 545 {
 546         { 0,
 547           0, 0,
 548           &do_msg_ini_msgfifo},
 549         { 0,
 550           1, 2,
 551           &do_msg_ini_memfifo},
 552         { 1,
 553           1, 1,
 554           &do_msg_char_out},
 555         { 0xff,                         /* end mark */
 556           0, 0,
 557           0},
 558
 559 };
 560
 561
 562
 563
 564 void do_message(int len, uint8_t *msg)
 565 {
 566         uint8_t fct, sub_fct;
 567         int i = 0;
 568
 569         if (len >= 2) {
 570                 fct = *msg++;
 571                 sub_fct = *msg++;
 572                 len -= 2;
 573
 574                 while (fct != z80_messages[i].fct)
 575                         ++i;
 576
 577                 if (z80_messages[i].fct == 0xff) {
 578                         DBG_P(1, "do_message: Unknown function: %i, %i\n",
 579                                         fct, sub_fct);
 580                         return; /* TODO: unknown message # */
 581                 }
 582
 583                 while (fct == z80_messages[i].fct) {
 584                         if (sub_fct >= z80_messages[i].sub_min && sub_fct <= z80_messages[i].sub_max )
 585                                 break;
 586                         ++i;
 587                 }
 588
 589                 if (z80_messages[i].fct != fct) {
 590                         DBG_P(1, "do_message: Unknown sub function: %i, %i\n",
 591                                         fct, sub_fct);
 592                         return; /* TODO: unknown message sub# */
 593                 }
 594
 595                 (z80_messages[i].func)(sub_fct, len, msg);
 596
 597
 598         } else {
 599                 /* TODO: error */
 600                 DBG_P(1, "do_message: to few arguments (%i); this shouldn't happen!\n", len);
 601         }
 602 }
 603
 604
 605
 606 #define CTRBUF_LEN 256
 607
 608 void check_msg_fifo(void)
 609 {
 610         int ch;
 611         static int state;
 612         static int msglen,idx;
 613         static uint8_t buffer[CTRBUF_LEN];
 614
 615         while (state != 3 && (ch = z80_msg_fifo_getc()) >= 0) {
 616                 switch (state) {
 617                 case 0:         /* wait for start of message */
 618                         if (ch == 0x81) {
 619                                 msglen = 0;
 620                                 idx = 0;
 621                                 state = 1;
 622                         }
 623                         break;
 624                 case 1:         /* get msg len */
 625                         if (ch > 0 && ch <= CTRBUF_LEN) {
 626                                 msglen = ch;
 627                                 state = 2;
 628                         } else
 629                                 state = 0;
 630                         break;
 631                 case 2:         /* get message */
 632                         buffer[idx++] = ch;
 633                         if (idx == msglen)
 634                                 state = 3;
 635                         break;
 636                 }
 637         }
 638
 639         if (state == 3) {
 640                 do_message(msglen, buffer);
 641                 state = 0;
 642         }
 643 }
 644
 645
 646 void z80_load_mem(void)
 647 {
 648
 649 DBG_P(1, "Loading z80 memory... \n");
 650
 651         unsigned sec = 0;
 652         uint32_t sec_base = hdrom_start;
 653
 654         while (sec < hdrom_sections) {
 655                 DBG_P(2, "  From: 0x%.5lX to: 0x%.5lX    (%5li bytes)\n",
 656                                 hdrom_address[sec],
 657                                 hdrom_address[sec]+hdrom_length_of_sections[sec] - 1,
 658                                 hdrom_length_of_sections[sec]);
 659
 660                 z80_write_block((unsigned char *) &hdrom[sec_base],  /* src */
 661                                 hdrom_address[sec],                  /* dest */
 662                                 hdrom_length_of_sections[sec]);      /* len */
 663                 sec_base+=hdrom_length_of_sections[sec];
 664                 sec++;
 665         }
 666 }
 667 /*--------------------------------------------------------------------------*/
 668
 669 int main(void)
 670 {
 671         //uint32_t led_state = LED_BLUE_PIN;
 672         //uint32_t rc;
 673         //uint8_t startval = 0;
 674         //int count;
 675         int state = 0;
 676         int ch;
 677
 678         clock_setup();
 679         gpio_setup();
 680         tim3_setup();
 681         setvbuf(stdout, NULL, _IONBF, 0);
 682         serial_setup();
 683         printf("\n(STM32F100+HD64180)_stamp Tester\n");
 684
 685         DBG_P(1, "z80_setup_bus... ");
 686         z80_setup_msg_fifo();
 687         z80_setup_bus();
 688         DBG_P(1, "done.\n");
 689
 690         /*
 691          * If the RTC is pre-configured just allow access, don't reconfigure.
 692          * Otherwise enable it with the LSE as clock source and 0x7fff as
 693          * prescale value.
 694          */
 695         rtc_auto_awake(LSE, 0x7fff);
 696
 697         systick_setup();
 698
 699         DBG_P(1, "Get bus... ");
 700         z80_busreq(LOW);
 701         z80_reset(HIGH);
 702         z80_request_bus();
 703         DBG_P(1, "got it!\n");
 704
 705         z80_memset(0, 0x76, 0x80000);
 706         //z80_sram_fill(0, 512 * 1024, 0x76, 0);
 707         z80_sram_cmp(0, 512 * 1024, 0x76, 0);
 708
 709         z80_load_mem();
 710         z80_reset(LOW);
 711         DBG_P(1, "Bus released!\n");
 712         z80_release_bus();
 713         z80_reset(HIGH);
 714         DBG_P(1, "Reset released!\n");
 715
 716
 717         ledset(0, BLINK1, 50);
 718
 719         while (1) {
 720
 721                 if (Stat & S_10MS_TO) {
 722                         Stat &= ~S_10MS_TO;
 723                         do_10ms();
 724                 }
 725
 726                 if (get_key_short(KEY0)) {
 727                         z80_reset_pulse();
 728                 }
 729
 730                 if ((ch = serial_getc()) >= 0) {
 731                         switch (state) {
 732                         case 0:
 733                                 if (ch == ESCCHAR) {
 734                                         state = 1;
 735                                         /* TODO: Timer starten */
 736                                 } else
 737                                         z80_memfifo_putc(fifo_out, ch);
 738                                 break;
 739                         case 1:
 740                                 switch (ch) {
 741
 742                                 case 'h': /* test: green led on */
 743                                         tim3_set(-1);
 744                                         break;
 745                                 case 'l': /* test: green led off */
 746                                         tim3_set(0);
 747                                         break;
 748                                 case 'p': /* test: pulse on led pin */
 749                                         tim3_set(24000000 / 1000000 * 5); /* 5 us */
 750                                         break;
 751                                 case 'r':
 752                                         z80_reset_pulse();
 753                                         break;
 754
 755                                 case ESCCHAR:
 756                                 default:
 757                                         z80_memfifo_putc(fifo_out, ch);
 758                                 }
 759                                 state = 0;
 760                                 break;
 761                         }
 762                 }
 763
 764                 check_msg_fifo();
 765         }
 766
 767         return 0;
 768 }