APM32E030的USART驱动(DMA)
USART 外设的通信速率最高为 6Mbit/s，同时支持DMA传输方式。
USART驱动代码如下：
/* 串口 */
#define UART_INS (USART1)
/* 接收数据大小 */
#define UART_RX_LEN (512)
/* 接收缓存 */
uint8_t rx_buf;
/* 接收长度 */
uint16_t rx_len;
/* 接收完成 */
uint16_t rx_complete;
/* 发送索引 */
uint16_t tx_index;
/* 发送长度 */
uint16_t tx_len;
/* 发送缓存 */
uint8_t *tx_buf;/*
* @brief 初始化
*
* @param None
*
* @retval None
*
*/
void bsp_uart_init(void)
{
GPIO_Config_T gpioConfig;
USART_Config_T configStruct;
DMA_Config_T dmaConfig;
/* GPIO */
RCM_EnableAHBPeriphClock(RCM_AHB_PERIPH_GPIOB);
GPIO_ConfigStructInit(&gpioConfig);
gpioConfig.pin = GPIO_PIN_6 | GPIO_PIN_7;
gpioConfig.mode = GPIO_MODE_AF;
gpioConfig.outtype = GPIO_OUT_TYPE_PP;
gpioConfig.speed = GPIO_SPEED_50MHz;
gpioConfig.pupd = GPIO_PUPD_NO;
GPIO_Config(GPIOB, &gpioConfig);
/* TX */
GPIO_ConfigPinAF(GPIOB, GPIO_PIN_SOURCE_6, GPIO_AF_PIN0);
/* RX */
GPIO_ConfigPinAF(GPIOB, GPIO_PIN_SOURCE_7, GPIO_AF_PIN0);
/* DMA */
RCM_EnableAHBPeriphClock(RCM_AHB_PERIPH_DMA1);
DMA_ConfigStructInit(&dmaConfig);
/* DMA -> USART_RX */
dmaConfig.direction = DMA_DIR_PERIPHERAL;
dmaConfig.circular = DMA_CIRCULAR_DISABLE;
dmaConfig.memoryTomemory = DMA_M2M_DISABLE;
dmaConfig.priority = DMA_PRIORITY_LEVEL_LOW;
dmaConfig.memoryInc = DMA_MEMORY_INC_ENABLE;
dmaConfig.peripheralInc = DMA_PERIPHERAL_INC_DISABLE;
dmaConfig.memoryDataSize = DMA_MEMORY_DATASIZE_BYTE;
dmaConfig.peripheralDataSize = DMA_PERIPHERAL_DATASIZE_BYTE;
dmaConfig.bufferSize = sizeof(rx_buf);
dmaConfig.memoryAddress = (uint32_t)rx_buf;
dmaConfig.peripheralAddress = (uint32_t)&UART_INS->RXDATA;
DMA_Config(DMA1_CHANNEL_3, &dmaConfig);
/* 传输完成中断 */
DMA_EnableInterrupt(DMA1_CHANNEL_3, DMA_INT_TFIE);
/* DMA -> USART_TX */
dmaConfig.direction = DMA_DIR_MEMORY;
dmaConfig.circular = DMA_CIRCULAR_DISABLE;
dmaConfig.memoryTomemory = DMA_M2M_DISABLE;
dmaConfig.priority = DMA_PRIORITY_LEVEL_LOW;
dmaConfig.memoryInc = DMA_MEMORY_INC_ENABLE;
dmaConfig.peripheralInc = DMA_PERIPHERAL_INC_DISABLE;
dmaConfig.memoryDataSize = DMA_MEMORY_DATASIZE_BYTE;
dmaConfig.peripheralDataSize = DMA_PERIPHERAL_DATASIZE_BYTE;
dmaConfig.bufferSize = sizeof(rx_buf);
dmaConfig.memoryAddress = 0;
dmaConfig.peripheralAddress = (uint32_t)&UART_INS->TXDATA;
DMA_Config(DMA1_CHANNEL_2, &dmaConfig);
/* 传输完成中断 */
DMA_EnableInterrupt(DMA1_CHANNEL_2, DMA_INT_TFIE);
/* 使能中断 */
NVIC_SetPriority(DMA1_CH2_3_IRQn, 0);
NVIC_EnableIRQ(DMA1_CH2_3_IRQn);
/* USART */
RCM_EnableAPB2PeriphClock(RCM_APB2_PERIPH_USART1);
USART_Reset(UART_INS);
USART_ConfigStructInit(&configStruct);
configStruct.baudRate = 115200;
configStruct.wordLength = USART_WORD_LEN_8B;
configStruct.stopBits = USART_STOP_BIT_1;
configStruct.parity = USART_PARITY_NONE ;
configStruct.mode = USART_MODE_TX_RX;
configStruct.hardwareFlowCtrl = USART_FLOW_CTRL_NONE;
USART_Config(UART_INS, &configStruct);
USART_EnableDMA(UART_INS, USART_DMA_REQUEST_RX);
USART_EnableDMA(UART_INS, USART_DMA_REQUEST_TX);
/* 使能空闲中断 */
USART_EnableInterrupt(UART_INS, USART_INT_IDLEIE);
/* 使能中断 */
NVIC_SetPriority(USART1_IRQn, 0);
NVIC_EnableIRQ(USART1_IRQn);
/* 使能串口 */
USART_Enable(UART_INS);
/* 接收数据 */
bsp_uart_recv();
}/*
* @brief 串口中断
*
* @param None
*
* @retval None
*
*/
void USART1_IRQHandler(void)
{
uint16_t num = 0;
/* 空闲 */
if (USART_ReadIntFlag(UART_INS, USART_INT_FLAG_IDLE) != RESET) {
USART_ClearIntFlag(UART_INS, USART_INT_FLAG_IDLE);
/* 计算已经传输的数据量 */
num = sizeof(rx_buf) - DMA_ReadDataNumber(DMA1_CHANNEL_3);
if (num != 0) {
rx_len = num;
rx_complete = 1;
}
bsp_uart_recv();
}
}/*
* @brief DMA中断
*
* @param None
*
* @retval None
*
*/
void DMA1_CH2_3_IRQHandler(void)
{
uint16_t num = 0;
/* USART TX */
if (DMA_ReadIntFlag(DMA1_INT_FLAG_TF2) != RESET) {
DMA_ClearIntFlag(DMA1_INT_FLAG_TF2);
}
/* USART RX */
if (DMA_ReadIntFlag(DMA1_INT_FLAG_TF3) != RESET) {
DMA_ClearIntFlag(DMA1_INT_FLAG_TF3);
/* 计算已经传输的数据量 */
num = sizeof(rx_buf) - DMA_ReadDataNumber(DMA1_CHANNEL_3);
if (num != 0) {
rx_len = num;
rx_complete = 1;
}
bsp_uart_recv();
}
}/*
* @brief 接收数据
*
* @param None
*
* @retval None
*
*/
void bsp_uart_recv(void)
{
DMA_Disable(DMA1_CHANNEL_3);
DMA_SetDataNumber(DMA1_CHANNEL_3, sizeof(rx_buf));
DMA_Enable(DMA1_CHANNEL_3);
}/*
* @brief 发送数据
*
* @param buf: 数据缓存
* buf_len: 缓存大小
*
* @retval None
*
*/
void bsp_uart_send(uint8_t *buf, uint16_t buf_len)
{
if ((buf != NULL) && (buf_len > 0)) {
DMA_Disable(DMA1_CHANNEL_2);
DMA_SetDataNumber(DMA1_CHANNEL_2, buf_len);
DMA1_CHANNEL_2->CHMADDR = (uint32_t)buf;
DMA_Enable(DMA1_CHANNEL_2);
}
}/*
* @brief 接收完成
*
* @param None
*
* @retval 0: 未完成; 1: 完成
*
*/
uint8_t bsp_is_rx_complete(void)
{
uint8_t ret = rx_complete;
rx_complete = 0;
return ret;
}/*
* @brief 获取接收长度
*
* @param None
*
* @retval 接收数据长度
*
*/
uint16_t bsp_get_rx_len(void)
{
uint16_t ret = rx_len;
rx_len = 0;
return ret;
}/*
* @brief 获取接收缓存
*
* @param None
*
* @retval 接收缓存
*
*/
uint8_t *bsp_get_rx_buf(void)
{
return rx_buf;
}
测试代码如下：
// 应用初始化
void app_init(void)
{
bsp_uart_init();
}
// 应用任务
void app_task(void)
{
/* 接收完成再发出来 */
if (bsp_is_rx_complete() != 0) {
bsp_uart_send(bsp_get_rx_buf(), bsp_get_rx_len());
}
}详细代码，请查看附件：
楼主的串口的接收与发送都使用的是DMA的方式。
好强大啊 学习到了，配置DMA发送的时候要先将DMAdisable，才能配置新的参数。 代码中DMA的配置看起来是正确的，确保你的硬件连接也是正确的，这样才能保证通信正常。
这要是6Mbps全部使用中断的方式接收，MCU的性能损耗应该也是蛮严重的。
DMA接收估计是唯一解
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