dmx/firmware/main.c

   1 /*
   2  *      DMX512 Interface
   3  *
   4  *      (c) 2020 Martin Mareš <mj@ucw.cz>
   5  */
   6
   7 #include "util.h"
   8 #include "interface.h"
   9
  10 #include <libopencm3/cm3/cortex.h>
  11 #include <libopencm3/cm3/nvic.h>
  12 #include <libopencm3/cm3/systick.h>
  13 #include <libopencm3/cm3/scb.h>
  14 #include <libopencm3/stm32/rcc.h>
  15 #include <libopencm3/stm32/desig.h>
  16 #include <libopencm3/stm32/gpio.h>
  17 #include <libopencm3/stm32/timer.h>
  18 #include <libopencm3/stm32/usart.h>
  19 #include <libopencm3/usb/dfu.h>
  20 #include <libopencm3/usb/usbd.h>
  21
  22 #include <string.h>
  23
  24 /*** Hardware init ***/
  25
  26 static void clock_init(void)
  27 {
  28         rcc_clock_setup_in_hse_8mhz_out_72mhz();
  29
  30         rcc_periph_clock_enable(RCC_GPIOA);
  31         rcc_periph_clock_enable(RCC_GPIOB);
  32         rcc_periph_clock_enable(RCC_GPIOC);
  33         rcc_periph_clock_enable(RCC_TIM3);
  34         rcc_periph_clock_enable(RCC_USART1);
  35         rcc_periph_clock_enable(RCC_USART3);
  36         rcc_periph_clock_enable(RCC_USB);
  37
  38         rcc_periph_reset_pulse(RST_GPIOA);
  39         rcc_periph_reset_pulse(RST_GPIOB);
  40         rcc_periph_reset_pulse(RST_GPIOC);
  41         rcc_periph_reset_pulse(RST_TIM3);
  42         rcc_periph_reset_pulse(RST_USART1);
  43         rcc_periph_reset_pulse(RST_USART3);
  44         rcc_periph_reset_pulse(RST_USB);
  45 }
  46
  47 static void gpio_init(void)
  48 {
  49         // PA9 = TXD1 for debugging console
  50         // PA10 = RXD1 for debugging console
  51         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO9);
  52         gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO10);
  53
  54         // PC13 = BluePill LED
  55         gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
  56         gpio_clear(GPIOC, GPIO13);
  57
  58         // PB10 = TXD3 for DMX
  59         // PB11 = RXD3 for DMX
  60         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO10);
  61         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO11);
  62
  63         // PB1 = TX enable for DMX (always on)
  64         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO1);
  65         gpio_set(GPIOB, GPIO1);
  66 }
  67
  68 static void usart_init(void)
  69 {
  70         usart_set_baudrate(USART1, 115200);
  71         usart_set_databits(USART1, 8);
  72         usart_set_stopbits(USART1, USART_STOPBITS_1);
  73         usart_set_mode(USART1, USART_MODE_TX);
  74         usart_set_parity(USART1, USART_PARITY_NONE);
  75         usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
  76
  77         usart_enable(USART1);
  78 }
  79
  80 /*** System ticks ***/
  81
  82 static volatile u32 ms_ticks;
  83
  84 void sys_tick_handler(void)
  85 {
  86         ms_ticks++;
  87 }
  88
  89 static void tick_init(void)
  90 {
  91         systick_set_frequency(1000, CPU_CLOCK_MHZ * 1000000);
  92         systick_counter_enable();
  93         systick_interrupt_enable();
  94 }
  95
  96 static void delay_ms(uint ms)
  97 {
  98         u32 start_ticks = ms_ticks;
  99         while (ms_ticks - start_ticks < ms)
 100                 ;
 101 }
 102
 103 /*** DMX ***/
 104
 105 #define DMX_MAX_PACKET_SIZE 64
 106
 107 static volatile byte dmx_state;
 108 static byte dmx_packet[DMX_MAX_PACKET_SIZE];
 109 static byte dmx_pos, dmx_len;
 110
 111 static byte dmx_next_packet[DMX_MAX_PACKET_SIZE];
 112 static byte dmx_next_len;
 113
 114 #undef DEBUG_DMX
 115 #ifdef DEBUG_DMX
 116 #define DMX_DEBUG(ch) debug_putc(ch)
 117 #else
 118 #define DMX_DEBUG(ch) do { } while (0)
 119 #endif
 120
 121 enum dmx_state {
 122         DMX_STATE_IDLE = 0,
 123         DMX_STATE_BREAK,
 124         DMX_STATE_MARK,
 125         DMX_STATE_DATA,
 126         DMX_STATE_LAST_BYTE,
 127         DMX_STATE_GAP,
 128 };
 129
 130 static void dmx_init(void)
 131 {
 132         usart_set_baudrate(USART3, 250000);
 133         usart_set_databits(USART3, 8);
 134         usart_set_stopbits(USART3, USART_STOPBITS_2);
 135         usart_set_mode(USART3, USART_MODE_TX);
 136         usart_set_parity(USART3, USART_PARITY_NONE);
 137         usart_set_flow_control(USART3, USART_FLOWCONTROL_NONE);
 138         nvic_enable_irq(NVIC_USART3_IRQ);
 139
 140         usart_enable(USART3);
 141
 142         timer_set_prescaler(TIM3, CPU_CLOCK_MHZ - 1);   // 1 MHz
 143         timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
 144         timer_update_on_overflow(TIM3);
 145         timer_disable_preload(TIM3);
 146         timer_one_shot_mode(TIM3);
 147         timer_enable_irq(TIM3, TIM_DIER_UIE);
 148         nvic_enable_irq(NVIC_TIM3_IRQ);
 149
 150         // Until we get data from USB, send "turn everything off" packets
 151         memset(dmx_next_packet, 0, DMX_MAX_PACKET_SIZE);
 152         dmx_next_len = DMX_MAX_PACKET_SIZE;
 153 }
 154
 155 void tim3_isr(void)
 156 {
 157         if (TIM_SR(TIM3) & TIM_SR_UIF) {
 158                 TIM_SR(TIM3) &= ~TIM_SR_UIF;
 159                 switch (dmx_state) {
 160                         case DMX_STATE_BREAK:
 161                                 // Send mark for 50 μs
 162                                 DMX_DEBUG('m');
 163                                 dmx_state = DMX_STATE_MARK;
 164                                 gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, GPIO10);
 165                                 timer_set_period(TIM3, 199);
 166                                 timer_generate_event(TIM3, TIM_EGR_UG);
 167                                 timer_enable_counter(TIM3);
 168                                 break;
 169                         case DMX_STATE_MARK:
 170                                 // Start sending data bytes
 171                                 DMX_DEBUG('d');
 172                                 dmx_state = DMX_STATE_DATA;
 173                                 usart_enable_tx_interrupt(USART3);
 174                                 break;
 175                         case DMX_STATE_GAP:
 176                                 DMX_DEBUG('>');
 177                                 dmx_state = DMX_STATE_IDLE;
 178                                 break;
 179                 }
 180         }
 181 }
 182
 183 void usart3_isr(void)
 184 {
 185         u32 status = USART_SR(USART3);
 186
 187         if (dmx_state == DMX_STATE_DATA) {
 188                 if (status & USART_SR_TXE) {
 189                         if (dmx_pos < dmx_len) {
 190                                 DMX_DEBUG('.');
 191                                 usart_send(USART3, dmx_packet[dmx_pos++]);
 192                         } else {
 193                                 // The transmitter is double-buffered, so at this moment, it is transmitting
 194                                 // the last byte of the frame. Wait until transfer is completed.
 195                                 DMX_DEBUG('l');
 196                                 usart_disable_tx_interrupt(USART3);
 197                                 USART_CR1(USART3) |= USART_CR1_TCIE;
 198                                 dmx_state = DMX_STATE_LAST_BYTE;
 199                         }
 200                 }
 201         } else if (dmx_state == DMX_STATE_LAST_BYTE) {
 202                 // Transfer of the last byte is complete, but we have to wait
 203                 // before the start of the next packet: minimum time between two
 204                 // breaks must be at least 1204 μs. We already sent a 200μs break,
 205                 // 200μs mark, and dmx_len 44μs data slots.
 206                 USART_CR1(USART3) &= ~USART_CR1_TCIE;
 207                 uint sent = 200 + 200 + 44*dmx_len;
 208                 if (sent < 1300) {
 209                         DMX_DEBUG('g');
 210                         dmx_state = DMX_STATE_GAP;
 211                         timer_set_period(TIM3, 1300 - sent - 1);
 212                         timer_generate_event(TIM3, TIM_EGR_UG);
 213                         timer_enable_counter(TIM3);
 214                 } else {
 215                         DMX_DEBUG('>');
 216                         dmx_state = DMX_STATE_IDLE;
 217                 }
 218         }
 219 }
 220
 221 static void dmx_send(void)
 222 {
 223         if (dmx_state != DMX_STATE_IDLE)
 224                 return;
 225
 226         if (!dmx_len)
 227                 return;
 228
 229         dmx_pos = 0;
 230
 231         // Send break for 200 μs
 232         DMX_DEBUG('<');
 233         dmx_state = DMX_STATE_BREAK;
 234         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO10);
 235         gpio_clear(GPIOB, GPIO10);
 236
 237         timer_set_period(TIM3, 199);
 238         timer_generate_event(TIM3, TIM_EGR_UG);
 239         timer_enable_counter(TIM3);
 240 }
 241
 242 /*** USB ***/
 243
 244 static usbd_device *usbd_dev;
 245
 246 enum usb_string {
 247         STR_MANUFACTURER = 1,
 248         STR_PRODUCT,
 249         STR_SERIAL,
 250 };
 251
 252 static char usb_serial_number[13];
 253
 254 static const char *usb_strings[] = {
 255         "United Computer Wizards",
 256         "DMX512 Interface",
 257         usb_serial_number,
 258 };
 259
 260 static const struct usb_device_descriptor device = {
 261         .bLength = USB_DT_DEVICE_SIZE,
 262         .bDescriptorType = USB_DT_DEVICE,
 263         .bcdUSB = 0x0200,
 264         .bDeviceClass = 0xFF,
 265         .bDeviceSubClass = 0,
 266         .bDeviceProtocol = 0,
 267         .bMaxPacketSize0 = 64,
 268         .idVendor = DMX_USB_VENDOR,
 269         .idProduct = DMX_USB_PRODUCT,
 270         .bcdDevice = DMX_USB_VERSION,
 271         .iManufacturer = STR_MANUFACTURER,
 272         .iProduct = STR_PRODUCT,
 273         .iSerialNumber = STR_SERIAL,
 274         .bNumConfigurations = 1,
 275 };
 276
 277 static const struct usb_endpoint_descriptor endpoints[] = {{
 278         // Bulk end-point for sending values to DMX
 279         .bLength = USB_DT_ENDPOINT_SIZE,
 280         .bDescriptorType = USB_DT_ENDPOINT,
 281         .bEndpointAddress = 0x01,
 282         .bmAttributes = USB_ENDPOINT_ATTR_BULK,
 283         .wMaxPacketSize = 64,
 284         .bInterval = 1,
 285 }};
 286
 287 static const struct usb_interface_descriptor iface = {
 288         .bLength = USB_DT_INTERFACE_SIZE,
 289         .bDescriptorType = USB_DT_INTERFACE,
 290         .bInterfaceNumber = 0,
 291         .bAlternateSetting = 0,
 292         .bNumEndpoints = 1,
 293         .bInterfaceClass = 0xFF,
 294         .bInterfaceSubClass = 0,
 295         .bInterfaceProtocol = 0,
 296         .iInterface = 0,
 297         .endpoint = endpoints,
 298 };
 299
 300 static const struct usb_dfu_descriptor dfu_function = {
 301         .bLength = sizeof(struct usb_dfu_descriptor),
 302         .bDescriptorType = DFU_FUNCTIONAL,
 303         .bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
 304         .wDetachTimeout = 255,
 305         .wTransferSize = 1024,
 306         .bcdDFUVersion = 0x0100,
 307 };
 308
 309 static const struct usb_interface_descriptor dfu_iface = {
 310         .bLength = USB_DT_INTERFACE_SIZE,
 311         .bDescriptorType = USB_DT_INTERFACE,
 312         .bInterfaceNumber = 1,
 313         .bAlternateSetting = 0,
 314         .bNumEndpoints = 0,
 315         .bInterfaceClass = 0xFE,
 316         .bInterfaceSubClass = 1,
 317         .bInterfaceProtocol = 1,
 318         .iInterface = 0,
 319
 320         .extra = &dfu_function,
 321         .extralen = sizeof(dfu_function),
 322 };
 323
 324 static const struct usb_interface ifaces[] = {{
 325         .num_altsetting = 1,
 326         .altsetting = &iface,
 327 }, {
 328         .num_altsetting = 1,
 329         .altsetting = &dfu_iface,
 330 }};
 331
 332 static const struct usb_config_descriptor config = {
 333         .bLength = USB_DT_CONFIGURATION_SIZE,
 334         .bDescriptorType = USB_DT_CONFIGURATION,
 335         .wTotalLength = 0,
 336         .bNumInterfaces = 2,
 337         .bConfigurationValue = 1,
 338         .iConfiguration = 0,
 339         .bmAttributes = 0x80,
 340         .bMaxPower = 50,        // multiplied by 2 mA
 341         .interface = ifaces,
 342 };
 343
 344 static byte usb_configured;
 345 static uint8_t usbd_control_buffer[64];
 346
 347 static void dfu_detach_complete(usbd_device *dev UNUSED, struct usb_setup_data *req UNUSED)
 348 {
 349         // Reset to bootloader, which implements the rest of DFU
 350         debug_printf("Switching to DFU\n");
 351         debug_flush();
 352         scb_reset_core();
 353 }
 354
 355 static enum usbd_request_return_codes dfu_control_cb(usbd_device *dev UNUSED,
 356         struct usb_setup_data *req,
 357         uint8_t **buf UNUSED,
 358         uint16_t *len UNUSED,
 359         void (**complete)(usbd_device *dev, struct usb_setup_data *req))
 360 {
 361         if (req->bmRequestType != 0x21 || req->bRequest != DFU_DETACH)
 362                 return USBD_REQ_NOTSUPP;
 363
 364         *complete = dfu_detach_complete;
 365         return USBD_REQ_HANDLED;
 366 }
 367
 368 static void ep01_cb(usbd_device *dev, uint8_t ep UNUSED)
 369 {
 370         // We received a frame from the USB host
 371         uint len = usbd_ep_read_packet(dev, 0x01, dmx_next_packet, DMX_MAX_PACKET_SIZE);
 372         debug_printf("USB: Host sent %u bytes\n", len);
 373         dmx_next_len = len;
 374 }
 375
 376 static void set_config_cb(usbd_device *dev, uint16_t wValue UNUSED)
 377 {
 378         usbd_register_control_callback(
 379                 dev,
 380                 USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
 381                 USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
 382                 dfu_control_cb);
 383         usbd_ep_setup(dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64, ep01_cb);
 384         usb_configured = 1;
 385 }
 386
 387 static void reset_cb(void)
 388 {
 389         debug_printf("USB: Reset\n");
 390         usb_configured = 0;
 391 }
 392
 393 static volatile bool usb_event_pending;
 394
 395 void usb_lp_can_rx0_isr(void)
 396 {
 397         /*
 398          *  We handle USB in the main loop to avoid race conditions between
 399          *  USB interrupts and other code. However, we need an interrupt to
 400          *  up the main loop from sleep.
 401          *
 402          *  We set up only the low-priority ISR, because high-priority ISR handles
 403          *  only double-buffered bulk transfers and isochronous transfers.
 404          */
 405         nvic_disable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 406         usb_event_pending = 1;
 407 }
 408
 409 static void usb_init(void)
 410 {
 411         // Simulate USB disconnect
 412         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO11 | GPIO12);
 413         gpio_clear(GPIOA, GPIO11 | GPIO12);
 414         delay_ms(100);
 415
 416         usbd_dev = usbd_init(
 417                 &st_usbfs_v1_usb_driver,
 418                 &device,
 419                 &config,
 420                 usb_strings,
 421                 ARRAY_SIZE(usb_strings),
 422                 usbd_control_buffer,
 423                 sizeof(usbd_control_buffer)
 424         );
 425         usbd_register_reset_callback(usbd_dev, reset_cb);
 426         usbd_register_set_config_callback(usbd_dev, set_config_cb);
 427         usb_event_pending = 1;
 428 }
 429
 430 /*** Main ***/
 431
 432 int main(void)
 433 {
 434         clock_init();
 435         gpio_init();
 436         tick_init();
 437         usart_init();
 438         desig_get_unique_id_as_dfu(usb_serial_number);
 439
 440         debug_printf("Hail, Lord Damian! Thy DMX interface is ready.\n");
 441
 442         usb_init();
 443         dmx_init();
 444
 445         u32 last_blink = 0;
 446         u32 last_send = 0;
 447
 448         for (;;) {
 449                 if (ms_ticks - last_blink >= 100) {
 450                         debug_led_toggle();
 451                         last_blink = ms_ticks;
 452                         dmx_send();
 453                 }
 454
 455                 if (usb_event_pending) {
 456                         usbd_poll(usbd_dev);
 457                         usb_event_pending = 0;
 458                         nvic_clear_pending_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 459                         nvic_enable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 460                 }
 461
 462                 if (dmx_state == DMX_STATE_IDLE) {
 463                         if (dmx_next_len) {
 464                                 // We have a new packet to send
 465                                 debug_printf("Sending new packet: %d bytes\n", dmx_next_len);
 466                                 memcpy(dmx_packet, dmx_next_packet, dmx_next_len);
 467                                 dmx_len = dmx_next_len;
 468                                 dmx_next_len = 0;
 469                                 dmx_send();
 470                                 last_send = ms_ticks;
 471                         } else if (ms_ticks - last_send >= 100) {
 472                                 // Re-send every 100 ms
 473                                 // debug_printf("Re-send: %d bytes\n", dmx_len);
 474                                 dmx_send();
 475                                 last_send = ms_ticks;
 476                         }
 477                 }
 478
 479                 wait_for_interrupt();
 480         }
 481
 482         return 0;
 483 }