串口发送与接收
1、阻塞式发送
1.1、练习receive() 和Transmit()
测试1：测试接收发送函数 receive() 和 Transmit()
在main()中写入测试代码：将stm32接收的代码，再发送到调试助手
uint8_t buf[5];
void main(){
while(1){
//参数：huart1句柄，接收区首地址，传输字节数，超时时间
HAL_UART_Receive(&huart1, buf,5,0xFFFF);//在stm32接收
HAL_UART_Transmit(&huart1, buf,5,0xFFFF);//从stm32发出
}
}
1.2、printf()重定向
main.c写入代码，用printf重定向到调试工具，将stm32接收的代码，再发送到调试助手。
//重定向 printf
#include <stdio.h>
#ifdef __GNUC__
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#define GETCHAR_PROTOTYPE int __io_getchar(void)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#define GETCHAR_PROTOTYPE int fgetc(FILE *f)
#endif /* __GNUC__ */
PUTCHAR_PROTOTYPE {
HAL_UART_Transmit(&huart1, (uint8_t *) &ch, 1, 0xFFFF);
return ch;
}
GETCHAR_PROTOTYPE {
uint8_t ch = 0;
HAL_UART_Receive(&huart1, (uint8_t *) &ch, 1, 0xFFFF);
return __io_putchar(ch);
}
void main(){
while(){
int val=0;
printf("\r\n 请输入一个数字：");
scanf("%d", &val);
printf("%d \r\n",val);
}
}
2、非阻塞发送
配置一下CubeMX环境
SYS->serial wire
RCC->Crystal/Ceramic Resonator
NVIC->enable USART global interrupt
USART1->dma:具体如下图
DMA+空闲中断实现不定长接收
实现功能：发送3个单位以内的数据，返回给串口调试助手
main.c
uint8_t buffer[5];//接收区
void SystemClock_Config();
int main() {
HAL_Init();
SystemClock_Config();
MX_DMA_Init();
MX_USART1_UART_Init();
HAL_UART_Receive_DMA(&huart1, buffer, 3);//开启接收
__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);//空闲中断
while (1) {
}
void SystemClock_Config() {//TODO
void Error_Handler() {//TODO
}
dma.c
#include "dma.h"
void MX_DMA_Init(void){
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel4_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel4_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel4_IRQn);
/* DMA1_Channel5_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel5_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel5_IRQn);
}
usart.c
#include "usart.h"
UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_rx;
DMA_HandleTypeDef hdma_usart1_tx;
void MX_USART1_UART_Init(void) {
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
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();
}
}
void HAL_UART_MspInit(UART_HandleTypeDef *uartHandle) {
GPIO_InitTypeDef GPIO_InitStruct = {0};
if (uartHandle->Instance == USART1) {
/* 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_PULLUP;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USART1 DMA Init */
/* USART1_RX Init */
hdma_usart1_rx.Instance = DMA1_Channel5;
hdma_usart1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_rx.Init.Mode = DMA_NORMAL;
hdma_usart1_rx.Init.Priority = DMA_PRIORITY_LOW;
if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK) {
Error_Handler();
}
__HAL_LINKDMA(uartHandle, hdmarx, hdma_usart1_rx);
/* USART1_TX Init */
hdma_usart1_tx.Instance = DMA1_Channel4;
hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_tx.Init.Mode = DMA_NORMAL;
hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW;
if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK) {
Error_Handler();
}
__HAL_LINKDMA(uartHandle, hdmatx, hdma_usart1_tx);
/* USART1 interrupt Init */
HAL_NVIC_SetPriority(USART1_IRQn, 1, 0);
HAL_NVIC_EnableIRQ(USART1_IRQn);
}
}
stm32f1xx_it.c 添加如下代码，作用是：当发送数据没有充满时但状态为空闲，则立即发送数据而不是等待填充满再发送
void USART1_IRQHandler(void) {
//串口1的中断服务函数，判断是否为空闲状态
if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_IDLE) != RESET) {
__HAL_UART_CLEAR_IDLEFLAG(&huart1);
HAL_UART_DMAStop(&huart1);
uint8_t len = 3 - __HAL_DMA_GET_COUNTER(huart1.hdmarx);
HAL_UART_Transmit_DMA(&huart1, buffer, len);
HAL_UART_Receive_DMA(&huart1, buffer, 3);
}
HAL_UART_IRQHandler(&huart1);
}
