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_USART1);
  34         rcc_periph_clock_enable(RCC_USART3);
  35         rcc_periph_clock_enable(RCC_USB);
  36
  37         rcc_periph_reset_pulse(RST_GPIOA);
  38         rcc_periph_reset_pulse(RST_GPIOB);
  39         rcc_periph_reset_pulse(RST_GPIOC);
  40         rcc_periph_reset_pulse(RST_USART1);
  41         rcc_periph_reset_pulse(RST_USART3);
  42         rcc_periph_reset_pulse(RST_USB);
  43 }
  44
  45 static void gpio_init(void)
  46 {
  47         // PA9 = TXD1 for debugging console
  48         // PA10 = RXD1 for debugging console
  49         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO9);
  50         gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO10);
  51
  52         // PC13 = BluePill LED
  53         gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
  54         gpio_clear(GPIOC, GPIO13);
  55
  56         // PB10 = TXD3 for DMX
  57         // PB11 = RXD3 for DMX
  58         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, GPIO10);
  59         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO11);
  60 }
  61
  62 static void usart_init(void)
  63 {
  64         usart_set_baudrate(USART1, 115200);
  65         usart_set_databits(USART1, 8);
  66         usart_set_stopbits(USART1, USART_STOPBITS_1);
  67         usart_set_mode(USART1, USART_MODE_TX);
  68         usart_set_parity(USART1, USART_PARITY_NONE);
  69         usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
  70
  71         usart_enable(USART1);
  72 }
  73
  74 /*** System ticks ***/
  75
  76 static volatile u32 ms_ticks;
  77
  78 void sys_tick_handler(void)
  79 {
  80         ms_ticks++;
  81 }
  82
  83 static void tick_init(void)
  84 {
  85         systick_set_frequency(1000, CPU_CLOCK_MHZ * 1000000);
  86         systick_counter_enable();
  87         systick_interrupt_enable();
  88 }
  89
  90 static void delay_ms(uint ms)
  91 {
  92         u32 start_ticks = ms_ticks;
  93         while (ms_ticks - start_ticks < ms)
  94                 ;
  95 }
  96
  97 /*** DMX ***/
  98
  99 static void dmx_init(void)
 100 {
 101         usart_set_baudrate(USART3, 250000);
 102         usart_set_databits(USART3, 8);
 103         usart_set_stopbits(USART3, USART_STOPBITS_1);
 104         usart_set_mode(USART3, USART_MODE_TX);
 105         usart_set_parity(USART3, USART_PARITY_NONE);
 106         usart_set_flow_control(USART3, USART_FLOWCONTROL_NONE);
 107
 108         usart_enable(USART3);
 109 }
 110
 111 static void dmx_send(void)
 112 {
 113         delay_ms(1);
 114
 115         // Send break
 116         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO10);
 117         gpio_clear(GPIOB, GPIO10);
 118         delay_ms(1);
 119
 120         // Send space
 121         gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, GPIO10);
 122         delay_ms(1);
 123
 124         usart_send_blocking(USART3, 0x00);
 125         usart_send_blocking(USART3, 0x00);
 126         usart_send_blocking(USART3, 0xff);      // warm
 127         usart_send_blocking(USART3, 0x00);
 128         usart_send_blocking(USART3, 0x00);      // cold
 129 }
 130
 131 /*** USB ***/
 132
 133 static usbd_device *usbd_dev;
 134
 135 enum usb_string {
 136         STR_MANUFACTURER = 1,
 137         STR_PRODUCT,
 138         STR_SERIAL,
 139 };
 140
 141 static char usb_serial_number[13];
 142
 143 static const char *usb_strings[] = {
 144         "United Computer Wizards",
 145         "DMX512 Interface",
 146         usb_serial_number,
 147 };
 148
 149 static const struct usb_device_descriptor device = {
 150         .bLength = USB_DT_DEVICE_SIZE,
 151         .bDescriptorType = USB_DT_DEVICE,
 152         .bcdUSB = 0x0200,
 153         .bDeviceClass = 0xFF,
 154         .bDeviceSubClass = 0,
 155         .bDeviceProtocol = 0,
 156         .bMaxPacketSize0 = 64,
 157         .idVendor = DMX_USB_VENDOR,
 158         .idProduct = DMX_USB_PRODUCT,
 159         .bcdDevice = DMX_USB_VERSION,
 160         .iManufacturer = STR_MANUFACTURER,
 161         .iProduct = STR_PRODUCT,
 162         .iSerialNumber = STR_SERIAL,
 163         .bNumConfigurations = 1,
 164 };
 165
 166 static const struct usb_endpoint_descriptor endpoints[] = {{
 167         // Bulk end-point for sending values to DMX
 168         .bLength = USB_DT_ENDPOINT_SIZE,
 169         .bDescriptorType = USB_DT_ENDPOINT,
 170         .bEndpointAddress = 0x01,
 171         .bmAttributes = USB_ENDPOINT_ATTR_BULK,
 172         .wMaxPacketSize = 64,
 173         .bInterval = 1,
 174 }};
 175
 176 static const struct usb_interface_descriptor iface = {
 177         .bLength = USB_DT_INTERFACE_SIZE,
 178         .bDescriptorType = USB_DT_INTERFACE,
 179         .bInterfaceNumber = 0,
 180         .bAlternateSetting = 0,
 181         .bNumEndpoints = 1,
 182         .bInterfaceClass = 0xFF,
 183         .bInterfaceSubClass = 0,
 184         .bInterfaceProtocol = 0,
 185         .iInterface = 0,
 186         .endpoint = endpoints,
 187 };
 188
 189 static const struct usb_dfu_descriptor dfu_function = {
 190         .bLength = sizeof(struct usb_dfu_descriptor),
 191         .bDescriptorType = DFU_FUNCTIONAL,
 192         .bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
 193         .wDetachTimeout = 255,
 194         .wTransferSize = 1024,
 195         .bcdDFUVersion = 0x0100,
 196 };
 197
 198 static const struct usb_interface_descriptor dfu_iface = {
 199         .bLength = USB_DT_INTERFACE_SIZE,
 200         .bDescriptorType = USB_DT_INTERFACE,
 201         .bInterfaceNumber = 1,
 202         .bAlternateSetting = 0,
 203         .bNumEndpoints = 0,
 204         .bInterfaceClass = 0xFE,
 205         .bInterfaceSubClass = 1,
 206         .bInterfaceProtocol = 1,
 207         .iInterface = 0,
 208
 209         .extra = &dfu_function,
 210         .extralen = sizeof(dfu_function),
 211 };
 212
 213 static const struct usb_interface ifaces[] = {{
 214         .num_altsetting = 1,
 215         .altsetting = &iface,
 216 }, {
 217         .num_altsetting = 1,
 218         .altsetting = &dfu_iface,
 219 }};
 220
 221 static const struct usb_config_descriptor config = {
 222         .bLength = USB_DT_CONFIGURATION_SIZE,
 223         .bDescriptorType = USB_DT_CONFIGURATION,
 224         .wTotalLength = 0,
 225         .bNumInterfaces = 2,
 226         .bConfigurationValue = 1,
 227         .iConfiguration = 0,
 228         .bmAttributes = 0x80,
 229         .bMaxPower = 50,        // multiplied by 2 mA
 230         .interface = ifaces,
 231 };
 232
 233 static byte usb_configured;
 234 static uint8_t usbd_control_buffer[64];
 235
 236 static void dfu_detach_complete(usbd_device *dev UNUSED, struct usb_setup_data *req UNUSED)
 237 {
 238         // Reset to bootloader, which implements the rest of DFU
 239         debug_printf("Switching to DFU\n");
 240         debug_flush();
 241         scb_reset_core();
 242 }
 243
 244 static enum usbd_request_return_codes dfu_control_cb(usbd_device *dev UNUSED,
 245         struct usb_setup_data *req,
 246         uint8_t **buf UNUSED,
 247         uint16_t *len UNUSED,
 248         void (**complete)(usbd_device *dev, struct usb_setup_data *req))
 249 {
 250         if (req->bmRequestType != 0x21 || req->bRequest != DFU_DETACH)
 251                 return USBD_REQ_NOTSUPP;
 252
 253         *complete = dfu_detach_complete;
 254         return USBD_REQ_HANDLED;
 255 }
 256
 257 static void ep01_cb(usbd_device *dev, uint8_t ep UNUSED)
 258 {
 259         // We received a frame from the USB host
 260         byte buf[64];
 261         uint len = usbd_ep_read_packet(dev, 0x01, buf, sizeof(buf));
 262         debug_printf("USB: Host sent %u bytes\n", len);
 263 }
 264
 265 static void set_config_cb(usbd_device *dev, uint16_t wValue UNUSED)
 266 {
 267         usbd_register_control_callback(
 268                 dev,
 269                 USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
 270                 USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
 271                 dfu_control_cb);
 272         usbd_ep_setup(dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64, ep01_cb);
 273         usb_configured = 1;
 274 }
 275
 276 static void reset_cb(void)
 277 {
 278         debug_printf("USB: Reset\n");
 279         usb_configured = 0;
 280 }
 281
 282 static volatile bool usb_event_pending;
 283
 284 void usb_lp_can_rx0_isr(void)
 285 {
 286         /*
 287          *  We handle USB in the main loop to avoid race conditions between
 288          *  USB interrupts and other code. However, we need an interrupt to
 289          *  up the main loop from sleep.
 290          *
 291          *  We set up only the low-priority ISR, because high-priority ISR handles
 292          *  only double-buffered bulk transfers and isochronous transfers.
 293          */
 294         nvic_disable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 295         usb_event_pending = 1;
 296 }
 297
 298 static void usb_init(void)
 299 {
 300         // Simulate USB disconnect
 301         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO11 | GPIO12);
 302         gpio_clear(GPIOA, GPIO11 | GPIO12);
 303         delay_ms(100);
 304
 305         usbd_dev = usbd_init(
 306                 &st_usbfs_v1_usb_driver,
 307                 &device,
 308                 &config,
 309                 usb_strings,
 310                 ARRAY_SIZE(usb_strings),
 311                 usbd_control_buffer,
 312                 sizeof(usbd_control_buffer)
 313         );
 314         usbd_register_reset_callback(usbd_dev, reset_cb);
 315         usbd_register_set_config_callback(usbd_dev, set_config_cb);
 316         usb_event_pending = 1;
 317 }
 318
 319 /*** Main ***/
 320
 321 int main(void)
 322 {
 323         clock_init();
 324         gpio_init();
 325         tick_init();
 326         usart_init();
 327         desig_get_unique_id_as_dfu(usb_serial_number);
 328
 329         debug_printf("Hail, Lord Damian! Thy DMX interface is ready.\n");
 330
 331         usb_init();
 332         dmx_init();
 333
 334         u32 last_blink = 0;
 335
 336         for (;;) {
 337                 if (ms_ticks - last_blink >= 100) {
 338                         debug_led_toggle();
 339                         last_blink = ms_ticks;
 340                         dmx_send();
 341                 }
 342
 343                 if (usb_event_pending) {
 344                         usbd_poll(usbd_dev);
 345                         usb_event_pending = 0;
 346                         nvic_clear_pending_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 347                         nvic_enable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 348                 }
 349
 350                 wait_for_interrupt();
 351         }
 352
 353         return 0;
 354 }