feat: Enhance UART reception handling with IDLE line detection and hex dump functionality

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "editor.formatOnSave": false
+}

Core/Src/main.c

@@ -22,6 +22,8 @@
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
 #include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
 
 /* USER CODE END Includes */
 
@@ -45,8 +47,9 @@ UART_HandleTypeDef huart1;
 UART_HandleTypeDef huart2;
 
 /* USER CODE BEGIN PV */
-static uint8_t rx_buf[16];
+static uint8_t rx_buf[64];
-static volatile uint8_t rx_complete = 0;
+static bool rx_complete = false;
+static volatile uint16_t rx_length = 0;
 /* USER CODE END PV */
 
 /* Private function prototypes -----------------------------------------------*/
@@ -55,13 +58,65 @@ static void MX_GPIO_Init(void);
 static void MX_USART1_UART_Init(void);
 static void MX_USART2_UART_Init(void);
 /* USER CODE BEGIN PFP */
-
+static void hex_dump(const uint8_t *data, uint16_t len);
 /* USER CODE END PFP */
 
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
 static char heartbeat_buf[64];
 
+/**
+  * @brief  Print hex dump in ESP-IDF style
+  * @param  data: pointer to data buffer
+  * @param  len: length of data
+  * @retval None
+  */
+static void hex_dump(const uint8_t *data, uint16_t len)
+{
+	char line_buf[80];
+	
+	for (uint16_t i = 0; i < len; i += 16) {
+		// Print address
+		int pos = snprintf(line_buf, sizeof(line_buf), "0x%08lx   ", (unsigned long)(data + i));
+		
+		// Print hex values (first 8 bytes)
+		for (int j = 0; j < 8; j++) {
+			if (i + j < len) {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "%02x ", data[i + j]);
+			} else {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "   ");
+			}
+		}
+		
+		// Space between two groups
+		pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, " ");
+		
+		// Print hex values (second 8 bytes)
+		for (int j = 8; j < 16; j++) {
+			if (i + j < len) {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "%02x ", data[i + j]);
+			} else {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "   ");
+			}
+		}
+		
+		// Print ASCII representation
+		pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, " |");
+		for (int j = 0; j < 16 && (i + j) < len; j++) {
+			uint8_t c = data[i + j];
+			if (c >= 32 && c <= 126) {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "%c", c);
+			} else {
+				pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, ".");
+			}
+		}
+		pos += snprintf(line_buf + pos, sizeof(line_buf) - pos, "|\r\n");
+		
+		// Send line to UART1
+		HAL_UART_Transmit(&huart1, (uint8_t *)line_buf, (uint16_t)pos, HAL_MAX_DELAY);
+	}
+}
+
 /* USER CODE END 0 */
 
 /**
@@ -96,6 +151,8 @@ int main(void)
   MX_USART1_UART_Init();
   MX_USART2_UART_Init();
   /* USER CODE BEGIN 2 */
+  /* Enable UART IDLE interrupt */
+  __HAL_UART_ENABLE_IT(&huart2, UART_IT_IDLE);
   /* Start UART2 reception in interrupt mode */
   HAL_UART_Receive_IT(&huart2, rx_buf, sizeof(rx_buf));
   /* USER CODE END 2 */
@@ -121,16 +178,19 @@ int main(void)
 		
 		/* Check if data received from UART2 */
 		if (rx_complete) {
-			rx_complete = 0;
+			rx_complete = false;
+			uint16_t len = rx_length;
 			
-			/* Print received buffer as hex to UART1 */
+			/* Print header */
-			char hex_buf[64];
+			char header[32];
-			int hex_len = snprintf(hex_buf, sizeof(hex_buf), "RX: ");
+			int header_len = snprintf(header, sizeof(header), "RX[%u]:\r\n", len);
-			for (int i = 0; i < (int)sizeof(rx_buf) && hex_len < (int)sizeof(hex_buf) - 4; i++) {
+			HAL_UART_Transmit(&huart1, (uint8_t *)header, (uint16_t)header_len, HAL_MAX_DELAY);
-				hex_len += snprintf(hex_buf + hex_len, sizeof(hex_buf) - hex_len, "%02X ", rx_buf[i]);
+			
-			}
+			/* Print received buffer as hex dump */
-			hex_len += snprintf(hex_buf + hex_len, sizeof(hex_buf) - hex_len, "\r\n");
+			hex_dump(rx_buf, len);
-			HAL_UART_Transmit(&huart1, (uint8_t *)hex_buf, (uint16_t)hex_len, HAL_MAX_DELAY);
+			
+			/* Clear buffer before re-arming */
+			memset(rx_buf, 0, sizeof(rx_buf));
 			
 			/* Re-arm UART2 reception */
 			HAL_UART_Receive_IT(&huart2, rx_buf, sizeof(rx_buf));
@@ -297,14 +357,34 @@ static void MX_GPIO_Init(void)
 /* USER CODE BEGIN 4 */
 
 /**
-  * @brief  Rx Transfer completed callback
+  * @brief  UART IDLE line detected callback
-  * @param  huart: UART handle
+  * @note   This is called from USART2_IRQHandler when IDLE interrupt occurs
   * @retval None
   */
-void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
+void UART_IDLE_Callback(UART_HandleTypeDef *huart)
 {
 	if (huart->Instance == USART2) {
-		rx_complete = 1;
+		if (huart->RxState != HAL_UART_STATE_BUSY_RX) {
+			/* Not in reception state, ignore */
+			return;
+		}
+		/* Calculate how many bytes were actually received */
+
+		/**
+		 * RxXferCount is a countdown timer maintained by the HAL library that
+		 * decrements with each byte received. Subtracting it from the total
+		 * gives you the actual number of bytes that made it into the buffer.
+		 */
+		rx_length = sizeof(rx_buf) - huart->RxXferCount;
+		
+		/* Only process if we actually received data */
+		if (rx_length > 0) {
+			/* Abort the ongoing reception */
+			HAL_UART_AbortReceive_IT(&huart2);
+			
+			/* Signal that data is ready */
+			rx_complete = true;
+		}
 	}
 }
 

Core/Src/stm32f4xx_it.c

@@ -219,7 +219,15 @@ void USART1_IRQHandler(void)
 void USART2_IRQHandler(void)
 {
   /* USER CODE BEGIN USART2_IRQn 0 */
+  /* Check for IDLE line detection */
+  if (__HAL_UART_GET_FLAG(&huart2, UART_FLAG_IDLE)) {
+    /* Clear IDLE flag by reading SR and DR */
+    __HAL_UART_CLEAR_IDLEFLAG(&huart2);
     
+    /* Call custom IDLE callback */
+    extern void UART_IDLE_Callback(UART_HandleTypeDef *huart);
+    UART_IDLE_Callback(&huart2);
+  }
   /* USER CODE END USART2_IRQn 0 */
   HAL_UART_IRQHandler(&huart2);
   /* USER CODE BEGIN USART2_IRQn 1 */