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