2 * Testing Communication with Sinclair Air Conditioner
4 * (c) 2023 Martin Mareš <mj@ucw.cz>
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>
24 /*** Hardware init ***/
26 static void clock_init(void)
28 rcc_clock_setup_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_72MHZ]);
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);
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);
47 static void gpio_init(void)
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);
54 // PC13 = BluePill LED
55 gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
56 gpio_clear(GPIOC, GPIO13);
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);
64 static void usart_init(void)
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);
76 /*** System ticks ***/
78 static volatile u32 ms_ticks;
80 void sys_tick_handler(void)
85 static void tick_init(void)
87 systick_set_frequency(1000, CPU_CLOCK_MHZ * 1000000);
88 systick_counter_enable();
89 systick_interrupt_enable();
92 static void delay_ms(uint ms)
94 u32 start_ticks = ms_ticks;
95 while (ms_ticks - start_ticks < ms)
99 /*** Emulated TM1618 LED Driver ***/
102 * Theory of operation:
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:
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
113 * No read commands are issued, so we can simulate TM1618 using a pure SPI slave.
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.
120 * Instead, we ignore STB* completely and implement a self-synchronizing receiver:
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.
126 * - Whenever 1 ms passes since the last byte was received, we reset the SPI.
127 * This allows us to recover from misaligned bytes.
130 static void tm_init(void)
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);
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);
154 * Data memory of TM1618:
156 * [0] . . . - - - - -
157 * [1] . . - - HEAT . . .
158 * [2] . . . DRY - SLP MED LOW
159 * [3] . . HIGH AUTO COOL . . .
160 * [4] . . . B2 - G2 D2 C2
161 * [5] . . E2 F2 A2 . . .
162 * [6] . . . B1 - G1 D1 C1
163 * [7] . . E1 F1 A1 . . .
165 * "." is an always-zero bit not defined by TM1618, "-" is defined, but not used by AC.
167 static volatile byte tm_data[8];
168 static volatile uint tm_overruns;
170 static volatile byte tm_buffer[256];
171 static volatile uint tm_len;
198 static const u16 tm_digits[10] = {
199 [0] = SEGa | SEGb | SEGc | SEGd | SEGe | SEGf,
201 [2] = SEGa | SEGb | SEGd | SEGe | SEGg,
202 [3] = SEGa | SEGb | SEGc | SEGd | SEGg,
203 [4] = SEGb | SEGc | SEGf | SEGg,
204 [5] = SEGa | SEGc | SEGd | SEGf | SEGg,
205 [6] = SEGa | SEGc | SEGd | SEGe | SEGf | SEGg,
206 [7] = SEGa | SEGb | SEGc,
207 [8] = SEGa | SEGb | SEGc | SEGd | SEGe | SEGf | SEGg,
208 [9] = SEGa | SEGb | SEGc | SEGd | SEGf | SEGg,
211 static volatile uint tm_timeouts;
215 if (SPI_SR(SPI2) & SPI_SR_OVR)
217 if (SPI_SR(SPI2) & SPI_SR_RXNE) {
218 byte x = SPI_DR(SPI2) ^ 0xff;
220 if (tm_len < ARRAY_SIZE(tm_buffer))
221 tm_buffer[tm_len++] = x;
223 static byte tm_address;
225 tm_data[tm_address & 7] = x;
227 } else if ((x & 0xc0) == 0xc0) {
230 timer_set_period(TIM3, 999);
231 timer_generate_event(TIM3, TIM_EGR_UG);
232 timer_enable_counter(TIM3);
238 if (TIM_SR(TIM3) & TIM_SR_UIF) {
239 TIM_SR(TIM3) &= ~TIM_SR_UIF;
241 spi_set_nss_high(SPI2);
242 spi_set_nss_low(SPI2);
246 static void tm_show(void)
249 for (uint i=0; i<8; i++)
250 debug_printf(" %02x", tm_data[i]);
251 debug_printf(" o=%d t=%d", tm_overruns, tm_timeouts);
254 if (tm_data[1] & 0x08)
255 debug_printf(" HEAT");
256 if (tm_data[2] & 0x10)
257 debug_printf(" DRY");
258 if (tm_data[2] & 0x04)
259 debug_printf(" SLEEP");
260 if (tm_data[2] & 0x02)
261 debug_printf(" MED");
262 if (tm_data[2] & 0x01)
263 debug_printf(" LOW");
264 if (tm_data[3] & 0x20)
265 debug_printf(" HIGH");
266 if (tm_data[3] & 0x10)
267 debug_printf(" AUTO");
268 if (tm_data[3] & 0x08)
269 debug_printf(" COOL");
272 for (int i=0; i<2; i++) {
273 uint x = (tm_data[7-2*i] << 8) | tm_data[6-2*i];
275 while (j < 10 && tm_digits[j] != x)
286 static byte tm_dumped;
287 if (!tm_dumped && tm_len == ARRAY_SIZE(tm_buffer)) {
288 for (uint i=0; i < tm_len; i++)
289 debug_printf("%02x ", tm_buffer[i]);
299 static usbd_device *usbd_dev;
302 STR_MANUFACTURER = 1,
307 static char usb_serial_number[13];
309 static const char *usb_strings[] = {
310 "United Computer Wizards",
311 "Sinclair Air Conditioner",
315 static const struct usb_device_descriptor device = {
316 .bLength = USB_DT_DEVICE_SIZE,
317 .bDescriptorType = USB_DT_DEVICE,
319 .bDeviceClass = 0xFF,
320 .bDeviceSubClass = 0,
321 .bDeviceProtocol = 0,
322 .bMaxPacketSize0 = 64,
326 .iManufacturer = STR_MANUFACTURER,
327 .iProduct = STR_PRODUCT,
328 .iSerialNumber = STR_SERIAL,
329 .bNumConfigurations = 1,
332 static const struct usb_endpoint_descriptor endpoints[] = {{
333 // Bulk end-point for sending values to the display
334 .bLength = USB_DT_ENDPOINT_SIZE,
335 .bDescriptorType = USB_DT_ENDPOINT,
336 .bEndpointAddress = 0x01,
337 .bmAttributes = USB_ENDPOINT_ATTR_BULK,
338 .wMaxPacketSize = 64,
342 static const struct usb_interface_descriptor iface = {
343 .bLength = USB_DT_INTERFACE_SIZE,
344 .bDescriptorType = USB_DT_INTERFACE,
345 .bInterfaceNumber = 0,
346 .bAlternateSetting = 0,
348 .bInterfaceClass = 0xFF,
349 .bInterfaceSubClass = 0,
350 .bInterfaceProtocol = 0,
352 .endpoint = endpoints,
355 static const struct usb_dfu_descriptor dfu_function = {
356 .bLength = sizeof(struct usb_dfu_descriptor),
357 .bDescriptorType = DFU_FUNCTIONAL,
358 .bmAttributes = USB_DFU_CAN_DOWNLOAD | USB_DFU_WILL_DETACH,
359 .wDetachTimeout = 255,
360 .wTransferSize = 1024,
361 .bcdDFUVersion = 0x0100,
364 static const struct usb_interface_descriptor dfu_iface = {
365 .bLength = USB_DT_INTERFACE_SIZE,
366 .bDescriptorType = USB_DT_INTERFACE,
367 .bInterfaceNumber = 1,
368 .bAlternateSetting = 0,
370 .bInterfaceClass = 0xFE,
371 .bInterfaceSubClass = 1,
372 .bInterfaceProtocol = 1,
375 .extra = &dfu_function,
376 .extralen = sizeof(dfu_function),
379 static const struct usb_interface ifaces[] = {{
381 .altsetting = &iface,
384 .altsetting = &dfu_iface,
387 static const struct usb_config_descriptor config = {
388 .bLength = USB_DT_CONFIGURATION_SIZE,
389 .bDescriptorType = USB_DT_CONFIGURATION,
392 .bConfigurationValue = 1,
394 .bmAttributes = 0x80,
395 .bMaxPower = 50, // multiplied by 2 mA
399 static byte usb_configured;
400 static uint8_t usbd_control_buffer[64];
402 static void dfu_detach_complete(usbd_device *dev UNUSED, struct usb_setup_data *req UNUSED)
404 // Reset to bootloader, which implements the rest of DFU
405 debug_printf("Switching to DFU\n");
410 static enum usbd_request_return_codes dfu_control_cb(usbd_device *dev UNUSED,
411 struct usb_setup_data *req,
412 uint8_t **buf UNUSED,
413 uint16_t *len UNUSED,
414 void (**complete)(usbd_device *dev, struct usb_setup_data *req))
416 if (req->bmRequestType != 0x21 || req->bRequest != DFU_DETACH)
417 return USBD_REQ_NOTSUPP;
419 *complete = dfu_detach_complete;
420 return USBD_REQ_HANDLED;
423 static void ep01_cb(usbd_device *dev, uint8_t ep UNUSED)
425 // We received a frame from the USB host
427 uint len = usbd_ep_read_packet(dev, 0x01, buf, 8);
428 debug_printf("USB: Host sent %u bytes\n", len);
431 static void set_config_cb(usbd_device *dev, uint16_t wValue UNUSED)
433 usbd_register_control_callback(
435 USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
436 USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
438 usbd_ep_setup(dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64, ep01_cb);
442 static void reset_cb(void)
444 debug_printf("USB: Reset\n");
448 static volatile bool usb_event_pending;
450 void usb_lp_can_rx0_isr(void)
453 * We handle USB in the main loop to avoid race conditions between
454 * USB interrupts and other code. However, we need an interrupt to
455 * up the main loop from sleep.
457 * We set up only the low-priority ISR, because high-priority ISR handles
458 * only double-buffered bulk transfers and isochronous transfers.
460 nvic_disable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
461 usb_event_pending = 1;
464 static void usb_init(void)
466 // Simulate USB disconnect
467 gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO11 | GPIO12);
468 gpio_clear(GPIOA, GPIO11 | GPIO12);
471 usbd_dev = usbd_init(
472 &st_usbfs_v1_usb_driver,
476 ARRAY_SIZE(usb_strings),
478 sizeof(usbd_control_buffer)
480 usbd_register_reset_callback(usbd_dev, reset_cb);
481 usbd_register_set_config_callback(usbd_dev, set_config_cb);
482 usb_event_pending = 1;
494 desig_get_unique_id_as_dfu(usb_serial_number);
496 debug_printf("Hello, world!\n");
504 if (ms_ticks - last_blink >= 1000) {
506 last_blink = ms_ticks;
510 if (usb_event_pending) {
512 usb_event_pending = 0;
513 nvic_clear_pending_irq(NVIC_USB_LP_CAN_RX0_IRQ);
514 nvic_enable_irq(NVIC_USB_LP_CAN_RX0_IRQ);
517 wait_for_interrupt();