test-sinclair/main.c

   1 /*
   2  *      Testing Communication with Sinclair Air Conditioner
   3  *
   4  *      (c) 2023 Martin Mareš <mj@ucw.cz>
   5  */
   6
   7 #include "util.h"
   8
   9 #include <libopencm3/cm3/cortex.h>
  10 #include <libopencm3/cm3/nvic.h>
  11 #include <libopencm3/cm3/systick.h>
  12 #include <libopencm3/cm3/scb.h>
  13 #include <libopencm3/stm32/rcc.h>
  14 #include <libopencm3/stm32/desig.h>
  15 #include <libopencm3/stm32/gpio.h>
  16 #include <libopencm3/stm32/usart.h>
  17 #include <libopencm3/stm32/spi.h>
  18 #include <libopencm3/stm32/timer.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_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_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_SPI2);
  34         rcc_periph_clock_enable(RCC_USART1);
  35         rcc_periph_clock_enable(RCC_USB);
  36         rcc_periph_clock_enable(RCC_TIM3);
  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_SPI2);
  42         rcc_periph_reset_pulse(RST_USART1);
  43         rcc_periph_reset_pulse(RST_USB);
  44         rcc_periph_reset_pulse(RST_TIM3);
  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         // PB12 = SS2 (but used as GP input)
  59         // PB13 = SCK2
  60         // PB15 = MOSI2
  61         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO12);
  62         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO13);
  63         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO15);
  64 }
  65
  66 static void usart_init(void)
  67 {
  68         usart_set_baudrate(USART1, 115200);
  69         usart_set_databits(USART1, 8);
  70         usart_set_stopbits(USART1, USART_STOPBITS_1);
  71         usart_set_mode(USART1, USART_MODE_TX);
  72         usart_set_parity(USART1, USART_PARITY_NONE);
  73         usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
  74
  75         usart_enable(USART1);
  76 }
  77
  78 /*** System ticks ***/
  79
  80 static volatile u32 ms_ticks;
  81
  82 void sys_tick_handler(void)
  83 {
  84         ms_ticks++;
  85 }
  86
  87 static void tick_init(void)
  88 {
  89         systick_set_frequency(1000, CPU_CLOCK_MHZ * 1000000);
  90         systick_counter_enable();
  91         systick_interrupt_enable();
  92 }
  93
  94 static void delay_ms(uint ms)
  95 {
  96         u32 start_ticks = ms_ticks;
  97         while (ms_ticks - start_ticks < ms)
  98                 ;
  99 }
 100
 101 /*** Emulated TM1618 LED Driver ***/
 102
 103 /*
 104  *  Theory of operation:
 105  *
 106  *  TM1618 communicates using a bi-directional SPI-like protocol.
 107  *  The AC unit is sending a stream of commands like this once per ca. 4 ms:
 108  *
 109  *      00 - set mode: 4 grids, 8 segments
 110  *      44 - will write to display memory, no auto-increment
 111  *      Cx - set memory address to x
 112  *      yy - data to write, two most-significant bits are always zero
 113  *      8B - display ON, duty cycle 10/16
 114  *
 115  *  No read commands are issued, so we can simulate TM1618 using a pure SPI slave.
 116  *
 117  *  Commands are delimited using the STB* (strobe) pin, but since our opto-couplers
 118  *  are negating, we cannot route this pin to SS (slave select) of our SPI.
 119  *  We tried triggering an external interrupt by this pin, but it turned out
 120  *  that the latency is too high.
 121  *
 122  *  Instead, we ignore STB* completely and implement a self-synchronizing receiver:
 123  *
 124  *    - The only byte which can have top 2 bits both set is the Cx command,
 125  *      so we can use this to find memory addresses and data in the stream.
 126  *      We can ignore all other commands.
 127  *
 128  *    - Whenever 1 ms passes since the last byte was received, we reset the SPI.
 129  *      This allows us to recover from misaligned bytes.
 130  */
 131
 132 static void tm_init(void)
 133 {
 134         // Configure SPI2 to receive
 135         spi_set_receive_only_mode(SPI2);
 136         spi_enable_software_slave_management(SPI2);
 137         spi_set_nss_low(SPI2);
 138         spi_send_lsb_first(SPI2);
 139         spi_set_clock_polarity_0(SPI2);
 140         spi_set_clock_phase_1(SPI2);
 141         spi_enable_rx_buffer_not_empty_interrupt(SPI2);
 142         nvic_enable_irq(NVIC_SPI2_IRQ);
 143         spi_enable(SPI2);
 144
 145         // TIM3 will handle receive timeout
 146         timer_set_prescaler(TIM3, CPU_CLOCK_MHZ-1);     // 1 tick = 1 μs
 147         timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_DOWN);
 148         timer_update_on_overflow(TIM3);
 149         timer_disable_preload(TIM3);
 150         timer_one_shot_mode(TIM3);
 151         timer_enable_irq(TIM3, TIM_DIER_UIE);
 152         nvic_enable_irq(NVIC_TIM3_IRQ);
 153 }
 154
 155 static volatile byte tm_data[8];
 156 static volatile byte tm_overrun;
 157
 158 static volatile byte tm_buffer[256];
 159 static volatile uint tm_len;
 160
 161 static volatile uint tm_timeouts;
 162
 163 void spi2_isr(void)
 164 {
 165         if (SPI_SR(SPI2) & SPI_SR_OVR)
 166                 tm_overrun = 1;
 167         if (SPI_SR(SPI2) & SPI_SR_RXNE) {
 168                 byte x = SPI_DR(SPI2) ^ 0xff;
 169 #if 0
 170                 if (tm_len < ARRAY_SIZE(tm_buffer))
 171                         tm_buffer[tm_len++] = x;
 172 #endif
 173                 static byte tm_address;
 174                 if (tm_address) {
 175                         tm_data[tm_address & 7] = x;
 176                         tm_address = 0;
 177                 } else if ((x & 0xc0) == 0xc0) {
 178                         tm_address = x;
 179                 }
 180                 timer_set_period(TIM3, 999);
 181                 timer_generate_event(TIM3, TIM_EGR_UG);
 182                 timer_enable_counter(TIM3);
 183         }
 184 }
 185
 186 void tim3_isr(void)
 187 {
 188         if (TIM_SR(TIM3) & TIM_SR_UIF) {
 189                 TIM_SR(TIM3) &= ~TIM_SR_UIF;
 190                 tm_timeouts++;
 191                 spi_set_nss_high(SPI2);
 192                 spi_set_nss_low(SPI2);
 193         }
 194 }
 195
 196 static void tm_show(void)
 197 {
 198         debug_printf("TM:");
 199         for (uint i=0; i<8; i++)
 200                 debug_printf(" %02x", tm_data[i]);
 201         debug_printf(" o=%d t=%d", tm_overrun, tm_timeouts);
 202         tm_overrun = 0;
 203         debug_putc('\n');
 204
 205 #if 0
 206         static byte tm_dumped;
 207         if (!tm_dumped && tm_len == ARRAY_SIZE(tm_buffer)) {
 208                 for (uint i=0; i < tm_len; i++)
 209                         debug_printf("%02x ", tm_buffer[i]);
 210                 debug_putc('\n');
 211                 // tm_dumped = 1;
 212                 tm_len = 0;
 213         }
 214 #endif
 215 }
 216
 217 /*** USB ***/
 218
 219 static usbd_device *usbd_dev;
 220
 221 enum usb_string {
 222         STR_MANUFACTURER = 1,
 223         STR_PRODUCT,
 224         STR_SERIAL,
 225 };
 226
 227 static char usb_serial_number[13];
 228
 229 static const char *usb_strings[] = {
 230         "United Computer Wizards",
 231         "Sinclair Air Conditioner",
 232         usb_serial_number,
 233 };
 234
 235 static const struct usb_device_descriptor device = {
 236         .bLength = USB_DT_DEVICE_SIZE,
 237         .bDescriptorType = USB_DT_DEVICE,
 238         .bcdUSB = 0x0200,
 239         .bDeviceClass = 0xFF,
 240         .bDeviceSubClass = 0,
 241         .bDeviceProtocol = 0,
 242         .bMaxPacketSize0 = 64,
 243         .idVendor = 0x4242,
 244         .idProduct = 0x0007,
 245         .bcdDevice = 0x0000,
 246         .iManufacturer = STR_MANUFACTURER,
 247         .iProduct = STR_PRODUCT,
 248         .iSerialNumber = STR_SERIAL,
 249         .bNumConfigurations = 1,
 250 };
 251
 252 static const struct usb_endpoint_descriptor endpoints[] = {{
 253         // Bulk end-point for sending values to the display
 254         .bLength = USB_DT_ENDPOINT_SIZE,
 255         .bDescriptorType = USB_DT_ENDPOINT,
 256         .bEndpointAddress = 0x01,
 257         .bmAttributes = USB_ENDPOINT_ATTR_BULK,
 258         .wMaxPacketSize = 64,
 259         .bInterval = 1,
 260 }};
 261
 262 static const struct usb_interface_descriptor iface = {
 263         .bLength = USB_DT_INTERFACE_SIZE,
 264         .bDescriptorType = USB_DT_INTERFACE,
 265         .bInterfaceNumber = 0,
 266         .bAlternateSetting = 0,
 267         .bNumEndpoints = 1,
 268         .bInterfaceClass = 0xFF,
 269         .bInterfaceSubClass = 0,
 270         .bInterfaceProtocol = 0,
 271         .iInterface = 0,
 272         .endpoint = endpoints,
 273 };
 274
 275 static const struct usb_dfu_descriptor dfu_function = {
 276         .bLength = sizeof(struct usb_dfu_descriptor),
 277         .bDescriptorType = DFU_FUNCTIONAL,
 278         .bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
 279         .wDetachTimeout = 255,
 280         .wTransferSize = 1024,
 281         .bcdDFUVersion = 0x0100,
 282 };
 283
 284 static const struct usb_interface_descriptor dfu_iface = {
 285         .bLength = USB_DT_INTERFACE_SIZE,
 286         .bDescriptorType = USB_DT_INTERFACE,
 287         .bInterfaceNumber = 1,
 288         .bAlternateSetting = 0,
 289         .bNumEndpoints = 0,
 290         .bInterfaceClass = 0xFE,
 291         .bInterfaceSubClass = 1,
 292         .bInterfaceProtocol = 1,
 293         .iInterface = 0,
 294
 295         .extra = &dfu_function,
 296         .extralen = sizeof(dfu_function),
 297 };
 298
 299 static const struct usb_interface ifaces[] = {{
 300         .num_altsetting = 1,
 301         .altsetting = &iface,
 302 }, {
 303         .num_altsetting = 1,
 304         .altsetting = &dfu_iface,
 305 }};
 306
 307 static const struct usb_config_descriptor config = {
 308         .bLength = USB_DT_CONFIGURATION_SIZE,
 309         .bDescriptorType = USB_DT_CONFIGURATION,
 310         .wTotalLength = 0,
 311         .bNumInterfaces = 2,
 312         .bConfigurationValue = 1,
 313         .iConfiguration = 0,
 314         .bmAttributes = 0x80,
 315         .bMaxPower = 50,        // multiplied by 2 mA
 316         .interface = ifaces,
 317 };
 318
 319 static byte usb_configured;
 320 static uint8_t usbd_control_buffer[64];
 321
 322 static void dfu_detach_complete(usbd_device *dev UNUSED, struct usb_setup_data *req UNUSED)
 323 {
 324         // Reset to bootloader, which implements the rest of DFU
 325         debug_printf("Switching to DFU\n");
 326         debug_flush();
 327         scb_reset_core();
 328 }
 329
 330 static enum usbd_request_return_codes dfu_control_cb(usbd_device *dev UNUSED,
 331         struct usb_setup_data *req,
 332         uint8_t **buf UNUSED,
 333         uint16_t *len UNUSED,
 334         void (**complete)(usbd_device *dev, struct usb_setup_data *req))
 335 {
 336         if (req->bmRequestType != 0x21 || req->bRequest != DFU_DETACH)
 337                 return USBD_REQ_NOTSUPP;
 338
 339         *complete = dfu_detach_complete;
 340         return USBD_REQ_HANDLED;
 341 }
 342
 343 static void ep01_cb(usbd_device *dev, uint8_t ep UNUSED)
 344 {
 345         // We received a frame from the USB host
 346         byte buf[8];
 347         uint len = usbd_ep_read_packet(dev, 0x01, buf, 8);
 348         debug_printf("USB: Host sent %u bytes\n", len);
 349 }
 350
 351 static void set_config_cb(usbd_device *dev, uint16_t wValue UNUSED)
 352 {
 353         usbd_register_control_callback(
 354                 dev,
 355                 USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
 356                 USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
 357                 dfu_control_cb);
 358         usbd_ep_setup(dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64, ep01_cb);
 359         usb_configured = 1;
 360 }
 361
 362 static void reset_cb(void)
 363 {
 364         debug_printf("USB: Reset\n");
 365         usb_configured = 0;
 366 }
 367
 368 static volatile bool usb_event_pending;
 369
 370 void usb_lp_can_rx0_isr(void)
 371 {
 372         /*
 373          *  We handle USB in the main loop to avoid race conditions between
 374          *  USB interrupts and other code. However, we need an interrupt to
 375          *  up the main loop from sleep.
 376          *
 377          *  We set up only the low-priority ISR, because high-priority ISR handles
 378          *  only double-buffered bulk transfers and isochronous transfers.
 379          */
 380         nvic_disable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 381         usb_event_pending = 1;
 382 }
 383
 384 static void usb_init(void)
 385 {
 386         // Simulate USB disconnect
 387         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO11 | GPIO12);
 388         gpio_clear(GPIOA, GPIO11 | GPIO12);
 389         delay_ms(100);
 390
 391         usbd_dev = usbd_init(
 392                 &st_usbfs_v1_usb_driver,
 393                 &device,
 394                 &config,
 395                 usb_strings,
 396                 ARRAY_SIZE(usb_strings),
 397                 usbd_control_buffer,
 398                 sizeof(usbd_control_buffer)
 399         );
 400         usbd_register_reset_callback(usbd_dev, reset_cb);
 401         usbd_register_set_config_callback(usbd_dev, set_config_cb);
 402         usb_event_pending = 1;
 403 }
 404
 405 /*** Main ***/
 406
 407 int main(void)
 408 {
 409         clock_init();
 410         gpio_init();
 411         usart_init();
 412
 413         tick_init();
 414         desig_get_unique_id_as_dfu(usb_serial_number);
 415
 416         debug_printf("Hello, world!\n");
 417
 418         tm_init();
 419         usb_init();
 420
 421         u32 last_blink = 0;
 422
 423         for (;;) {
 424                 if (ms_ticks - last_blink >= 1000) {
 425                         debug_led_toggle();
 426                         last_blink = ms_ticks;
 427                         tm_show();
 428                 }
 429
 430                 if (usb_event_pending) {
 431                         usbd_poll(usbd_dev);
 432                         usb_event_pending = 0;
 433                         nvic_clear_pending_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 434                         nvic_enable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
 435                 }
 436
 437                 wait_for_interrupt();
 438         }
 439
 440         return 0;
 441 }