add board_reset_to_bootloader(), try to implement that for ch32v203 but not working yet

examples/device/cdc_dual_ports/src/main.c

@@ -119,6 +119,26 @@ static void cdc_task(void) {
   }
 }
 
+// Invoked when cdc when line state changed e.g connected/disconnected
+// Use to reset to DFU when disconnect with 1200 bps
+void tud_cdc_line_state_cb(uint8_t instance, bool dtr, bool rts) {
+  (void)rts;
+
+  // DTR = false is counted as disconnected
+  if (!dtr) {
+    // touch1200 only with first CDC instance (Serial)
+    if (instance == 0) {
+      cdc_line_coding_t coding;
+      tud_cdc_get_line_coding(&coding);
+      if (coding.bit_rate == 1200) {
+        if (board_reset_to_bootloader) {
+          board_reset_to_bootloader();
+        }
+      }
+    }
+  }
+}
+
 //--------------------------------------------------------------------+
 // BLINKING TASK
 //--------------------------------------------------------------------+

hw/bsp/board_api.h

@@ -72,6 +72,9 @@ void board_init(void);
 // Init board after tinyusb is initialized
 void board_init_after_tusb(void) TU_ATTR_WEAK;
 
+// Jump to bootloader
+void board_reset_to_bootloader(void) TU_ATTR_WEAK;
+
 // Turn LED on or off
 void board_led_write(bool state);
 

hw/bsp/ch32v20x/boards/ch32v203c_r0_1v0/board.h

@@ -6,7 +6,7 @@ extern "C" {
 #endif
 
 #define LED_PORT       GPIOA
-#define LED_PIN        GPIO_Pin_15
+#define LED_PIN        GPIO_Pin_0
 #define LED_STATE_ON   0
 
 #define UART_DEV        USART1

hw/bsp/ch32v20x/boards/ch32v203g_r0_1v0/board.h

@@ -7,7 +7,7 @@ extern "C" {
 
 #define LED_PORT       GPIOA
 #define LED_PIN        GPIO_Pin_0
-#define LED_STATE_ON   1
+#define LED_STATE_ON   0
 
 #define UART_DEV        USART2
 #define UART_CLOCK_EN() RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE)

hw/bsp/ch32v20x/family.c

@@ -139,6 +139,34 @@ void board_init(void) {
   __enable_irq();
 }
 
+void board_reset_to_bootloader(void) {
+  board_led_write(true);
+
+  __disable_irq();
+
+#if CFG_TUD_ENABLED
+  tud_deinit(0);
+  RCC_APB1PeriphResetCmd(RCC_APB1Periph_USB, ENABLE);
+  RCC_APB1PeriphResetCmd(RCC_APB1Periph_USB, DISABLE);
+#endif
+
+  SysTick->CTLR = 0;
+  for (int i = WWDG_IRQn; i< DMA1_Channel8_IRQn; i++) {
+    NVIC_DisableIRQ(i);
+  }
+
+  __enable_irq();
+
+  // define function pointer to BOOT ROM address
+  void (*bootloader_entry)(void) = (void (*)(void))0x1FFF8000;
+
+  bootloader_entry();
+
+  board_led_write(false);
+
+  // while(1) { }
+}
+
 void board_led_write(bool state) {
   GPIO_WriteBit(LED_PORT, LED_PIN, state ? LED_STATE_ON : (1-LED_STATE_ON));
 }
@@ -166,3 +194,7 @@ int board_uart_write(void const *buf, int len) {
 
   return len;
 }
+
+//--------------------------------------------------------------------
+// Neopixel
+//--------------------------------------------------------------------