我必须从UART中断串行通信中接收未知长度的数据。我已经初始化了一个数组来存储数据。现在，当我收到数据并逐字节存储直到用户输入 时，数据应该被存储，并且在有一组新数据进来时不会被覆盖。为此，我想到初始化一个计数器，每当收到数据时，计数器应该递增，并且要存储在下一个寄存器中的数据。由于我对编程很陌生，我需要为STM32编写这种C语言，我该怎么做？
uint8_t rx_data [200];
int count = 0;
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
HAL_UART_Receive_IT (&huart2, rx_data);
count ++;
}
嗯，最好的方法是两个缓冲区和FreeRTOS。 问题是您可能不会一个接一个地接收，但可以一次获取字节数。所以你需要两个缓冲区："接收缓冲区"和"数据缓冲区"。此外，您可能需要某种"清除缓冲区"来清空其他缓冲区。这比循环中的空缓冲区更快。
所以，让我们看看。我为STM32F303写例子。首先在 CubeMX 中为 FreeRTOS 创建一个任务，让它成为consoleTaskHandle。然后在stm32f3xx_it.c中添加或编辑：
/* Private includes -----------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "cmsis_os.h"
/* USER CODE END Includes */
//........................
//........................
/* USER CODE BEGIN EV */
extern osThreadId consoleTaskHandle;
/* USER CODE END EV */
//........................
//........................
/**
* @brief This function handles USART2 global interrupt
*/
void USART2_IRQHandler(void) {
/* USER CODE BEGIN USART2_IRQn 0 */
BaseType_t xHigherPriorityTaskWoken;
xHigherPriorityTaskWoken = pdFALSE;
vTaskNotifyGiveFromISR(consoleTaskHandle, &xHigherPriorityTaskWoken);
portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
/* USER CODE END USART2_IRQn 0 */
HAL_UART_IRQHandler(&huart2);
/* USER CODE BEGIN USART2_IRQn 1 */
/* USER CODE END USART2_IRQn 1 */
}
这意味着，每次 IT 执行时，我们都会向 FreeRTOS 任务发送通知。
现在，让我们编写任务来处理我们接收到的数据。所以主要.c：
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <string.h>
#include <stdio.h>
/* USER CODE END Includes */
//........................
//........................
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USART */
#define USART_CONSOLE_BUFFER_SIZE ((uint8_t)64)
/* USER CODE END PD */
//........................
//........................
/* USER CODE BEGIN PV */
/* USART */
static const char emptyBuffer[USART_CONSOLE_BUFFER_SIZE] = {0x00};
char consoleRxBuffer[USART_CONSOLE_BUFFER_SIZE] = {0x00};
char consoleTxBuffer[USART_CONSOLE_BUFFER_SIZE] = {0x00};
/* USER CODE END PV */
//........................
//........................
/* USER CODE BEGIN Header_StartConsoleTask */
/**
* @brief Function implementing the consoleTask thread.
* @param argument: Not used
* @retval None
*/
/* USER CODE END Header_StartConsoleTask */
void StartConsoleTask(void const * argument) {
/* USER CODE BEGIN StartConsoleTask */
uint32_t ulNotifiedValue = 0;
static uint8_t rxBufferLen = 0; /*!< Current RX buffer length */
static uint8_t txBufferLen = 0; /*!< Current TX buffer length */
static uint8_t lastBufferLen = 0; /*!< Last RX buffer length */
static bool gotCommand = false; /*!< Recieved command flag */
char command[USART_CONSOLE_BUFFER_SIZE] = {0x00}; /*!< Command buffer */
if (HAL_UART_Receive_IT(&huart2, (uint8_t *)consoleRxBuffer, USART_CONSOLE_BUFFER_SIZE) != HAL_OK) {
// Uart error handle
}
for (;;) {
ulNotifiedValue = ulTaskNotifyTake(pdFALSE, (TickType_t) ULONG_MAX);
// Got notification from IT
if (ulNotifiedValue > 0) {
// Let's check the RX buffer first
rxBufferLen = strlen(consoleRxBuffer);
if (rxBufferLen > 0) {
// Let's send data back to console
// or we gonna print data blindly
if (rxBufferLen > lastBufferLen) {
/*
If the last symbol is 'r', then:
- Stop RX
- Send 'n' next
- Copy RX buffer to command buffer
- Empty RX buffer and start IT again
- Set 'GotCommand flag'
ELSE
- Simply send data back to cosole
*/
// Count amount of data to send back
txBufferLen = rxBufferLen - lastBufferLen;
// Copy data from RX buffer to TX buffer
strncpy(consoleTxBuffer, &consoleRxBuffer[lastBufferLen], txBufferLen);
consoleTxBuffer[txBufferLen] = ' ';
if (consoleRxBuffer[rxBufferLen - 1] == 'r') {
gotCommand = true;
HAL_UART_AbortReceive_IT(&huart2);
consoleTxBuffer[txBufferLen] = 'n';
consoleTxBuffer[txBufferLen + 1] = ' ';
/* Copy command from RX buffer to command buffer */
// Let's trim spaces from the beginning
uint8_t commandStartPos = 0;
for (int i = 0; i < USART_CONSOLE_BUFFER_SIZE; ++i) {
if (consoleRxBuffer[0] == ' ') {
commandStartPos++;
} else {
break;
}
}
strncpy(command, &consoleRxBuffer[commandStartPos], strlen(consoleRxBuffer) - commandStartPos + 1);
/*
Empty RX buffer
I clean it by copying empty buffer to RX. That increases memory
consumption, but works faster. You can do it in cycle.
*/
strncpy(consoleRxBuffer, emptyBuffer, USART_CONSOLE_BUFFER_SIZE);
lastBufferLen = 0;
// Start the UART IT again
if (HAL_UART_Receive_IT(&huart2, (uint8_t *)consoleRxBuffer, USART_CONSOLE_BUFFER_SIZE) != HAL_OK) {
// Uart error handle
}
} else {
lastBufferLen = rxBufferLen;
}
// Send data back to console through UART DMA (you must turn it on in settings)
if (HAL_UART_Transmit_DMA(&huart2, (uint8_t *)consoleTxBuffer, strlen(consoleTxBuffer)) != HAL_OK) {
// Uart error handle
}
while (__HAL_UART_GET_FLAG(&huart2, UART_FLAG_TC) == RESET) {
vTaskDelay(1);
}
}
/* If we got command in last condition */
if (gotCommand == true) {
gotCommand = false; // Reset flag
// Do some work with recieved command/data
}
}
}
}
}