在我们需要使用串口接收中断去解析大量指令或数据时,为了避免直接在串口中断函数中进行解析,可以使用环形队列作为缓冲区。
一、初始化结构体
将环形缓冲区的head
(队列头)和tail
(队列尾)都初始化为0,表示缓冲区是空的,头和尾指向同一个位置。
typedef struct {
uint8_t buffer[128];
uint16_t head;
uint16_t tail;
} CircularBuffer;
CircularBuffer rxBuffer;
void CircularBuffer_Init(CircularBuffer* cb) {
cb->head = 0;
cb->tail = 0;
}
二、写数据到队列
- 计算出下一个
head
位置next = (cb->head + 1) % RX_BUFFER_SIZE
,通过模运算确保head
位置在缓冲区大小范围内。 - 如果
next != cb->tail
,意味着缓冲区未满,可以写入数据。 - 将数据写入当前位置
cb->buffer[cb->head]
,然后更新head
为next
。 - 如果缓冲区已满(即
next == cb->tail
),则返回0,表示写入失败。 - 否则返回1,表示写入成功。
int CircularBuffer_Write(CircularBuffer* cb, uint8_t data) {
uint16_t next = (cb->head + 1) % RX_BUFFER_SIZE;
if (next != cb->tail) {
cb->buffer[cb->head] = data;
cb->head = next;
return 1;
}
return 0;
}
三、从队列读取数据
- 如果
head
和tail
不相等,表示缓冲区中有数据可以读取。 - 将数据从
cb->buffer[cb->tail]
中读取出来,并将其存储到data
指向的内存中。 - 更新
tail
为下一个位置(cb->tail + 1) % RX_BUFFER_SIZE
,确保尾指针循环回到缓冲区的起始位置。 - 如果缓冲区为空(
head == tail
),则返回0,表示读取失败。 - 否则返回1,表示读取成功。
int CircularBuffer_Read(CircularBuffer* cb, uint8_t* data) {
if (cb->head != cb->tail) {
*data = cb->buffer[cb->tail];
cb->tail = (cb->tail + 1) % RX_BUFFER_SIZE;
return 1;
}
return 0;
}
四、获取缓冲区长度
获取缓冲区中可用的数据字节数(即从tail
到head
之间的距离)。
uint16_t CircularBuffer_Available(CircularBuffer* cb) {
return (cb->head - cb->tail + RX_BUFFER_SIZE) % RX_BUFFER_SIZE;
}
代码示例
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file usart.c
* @brief This file provides code for the configuration
* of the USART instances.
******************************************************************************
* @attention
*
* Copyright (c) 2024 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "usart.h"
/* USER CODE BEGIN 0 */
#define RX_BUFFER_SIZE 128
uint8_t receivedByte;
CircularBuffer rxBuffer;
/* USER CODE END 0 */
UART_HandleTypeDef huart1;
UART_HandleTypeDef huart3;
/* USART1 init function */
void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
huart1.Instance = USART1;
huart1.Init.BaudRate = 9600;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
HAL_UART_Receive_IT(&huart1, &receivedByte, 1);
/* USER CODE END USART1_Init 2 */
}
/* USART3 init function */
void MX_USART3_UART_Init(void)
{
/* USER CODE BEGIN USART3_Init 0 */
/* USER CODE END USART3_Init 0 */
/* USER CODE BEGIN USART3_Init 1 */
/* USER CODE END USART3_Init 1 */
huart3.Instance = USART3;
huart3.Init.BaudRate = 9600;
huart3.Init.WordLength = UART_WORDLENGTH_8B;
huart3.Init.StopBits = UART_STOPBITS_1;
huart3.Init.Parity = UART_PARITY_NONE;
huart3.Init.Mode = UART_MODE_TX_RX;
huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart3.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart3) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART3_Init 2 */
/* USER CODE END USART3_Init 2 */
}
void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(uartHandle->Instance==USART1)
{
/* USER CODE BEGIN USART1_MspInit 0 */
/* USER CODE END USART1_MspInit 0 */
/* USART1 clock enable */
__HAL_RCC_USART1_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
/**USART1 GPIO Configuration
PA9 ------> USART1_TX
PA10 ------> USART1_RX
*/
GPIO_InitStruct.Pin = GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USART1 interrupt Init */
HAL_NVIC_SetPriority(USART1_IRQn, 3, 0);
HAL_NVIC_EnableIRQ(USART1_IRQn);
/* USER CODE BEGIN USART1_MspInit 1 */
/* USER CODE END USART1_MspInit 1 */
}
else if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspInit 0 */
/* USER CODE END USART3_MspInit 0 */
/* USART3 clock enable */
__HAL_RCC_USART3_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
/**USART3 GPIO Configuration
PB10 ------> USART3_TX
PB11 ------> USART3_RX
*/
GPIO_InitStruct.Pin = GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_11;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* USART3 interrupt Init */
HAL_NVIC_SetPriority(USART3_IRQn, 4, 0);
HAL_NVIC_EnableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspInit 1 */
/* USER CODE END USART3_MspInit 1 */
}
}
void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{
if(uartHandle->Instance==USART1)
{
/* USER CODE BEGIN USART1_MspDeInit 0 */
/* USER CODE END USART1_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_USART1_CLK_DISABLE();
/**USART1 GPIO Configuration
PA9 ------> USART1_TX
PA10 ------> USART1_RX
*/
HAL_GPIO_DeInit(GPIOA, GPIO_PIN_9|GPIO_PIN_10);
/* USART1 interrupt Deinit */
HAL_NVIC_DisableIRQ(USART1_IRQn);
/* USER CODE BEGIN USART1_MspDeInit 1 */
/* USER CODE END USART1_MspDeInit 1 */
}
else if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspDeInit 0 */
/* USER CODE END USART3_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_USART3_CLK_DISABLE();
/**USART3 GPIO Configuration
PB10 ------> USART3_TX
PB11 ------> USART3_RX
*/
HAL_GPIO_DeInit(GPIOB, GPIO_PIN_10|GPIO_PIN_11);
/* USART3 interrupt Deinit */
HAL_NVIC_DisableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspDeInit 1 */
/* USER CODE END USART3_MspDeInit 1 */
}
}
/* USER CODE BEGIN 1 */
int fputc(int ch, FILE *f)//printf
{
HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1,0xffff); //发送一个字节的数据到指定的串口
return (ch);
}
int fgetc(FILE * f)
{
uint8_t ch = 0;
HAL_UART_Receive(&huart1,&ch, 1, 0xffff);
return ch;
}
//初始化环形队列
void CircularBuffer_Init(CircularBuffer* cb) {
cb->head = 0;
cb->tail = 0;
}
//将数据添加到环形缓冲区
int CircularBuffer_Write(CircularBuffer* cb, uint8_t data) {
uint16_t next = (cb->head + 1) % RX_BUFFER_SIZE;
if (next != cb->tail) {
cb->buffer[cb->head] = data;
cb->head = next;
return 1;
}
return 0;
}
//从环形缓冲区读取数据
int CircularBuffer_Read(CircularBuffer* cb, uint8_t* data) {
if (cb->head != cb->tail) {
*data = cb->buffer[cb->tail];
cb->tail = (cb->tail + 1) % RX_BUFFER_SIZE;
return 1;
}
return 0;
}
//获取环形缓冲区中的字节
uint16_t CircularBuffer_Available(CircularBuffer* cb) {
return (cb->head - cb->tail + RX_BUFFER_SIZE) % RX_BUFFER_SIZE;
}
// USART1 中断回调函数
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance == USART1)
{
CircularBuffer_Write(&rxBuffer, receivedByte);
HAL_UART_Receive_IT(&huart1, (uint8_t*) &receivedByte, 1);
}
}
/* USER CODE END 1 */