【STM32U3评测】实现双通道串口通信系统

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donatello1996 发布时间：2025-5-23 17:55

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文章简介:	拿到了nucleo-U385开发板

拿到了nucleo-U385开发板，在KEIL环境下编程，需要下载CubeU3支持包，在ST官网即可下载，并且在CubeU3支持包内还有KEIL环境所需要的pack安装包，这个应该是最近才做的一个方便开发者开发的一个机制：

我直接用点灯的例程来改串口例程，方便省事：

整理好的例程结构如下：

根据原理图可以得知，开发板的STLINKV3 VCP连接的串口是UART1，即PA9 PA10，可以直接与电脑的串口助手进行通信，另外开发板上还有PA2 PA3引脚，这个引脚被复用为LPUART1：

我这个帖子就实现UART1和LPUART1的双通道串口通信，其中把LPUART1的接收功能打开，使用空闲中断和DMA进行接收，先看看UART1的初始化代码：

UART_HandleTypeDef huart1;
int fputc(int ch , FILE *f)
{
while ((USART1->ISR & 0X40) == 0);
USART1->TDR = (uint8_t)ch;
return ch;
}
void UART1_Init(uint32_t baud)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
__HAL_RCC_USART1_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
GPIO_InitStruct.Pin = GPIO_PIN_9 | GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
HAL_GPIO_Init(GPIOA , &GPIO_InitStruct);
huart1.Instance = USART1;
huart1.Init.BaudRate = baud;
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;
huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
HAL_UART_Init(&huart1);
}

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非常简单，只要熟悉STM32编程的没有一点难度，然后是LPUART1：

UART_HandleTypeDef hlpuart1;
DMA_NodeTypeDef Node_GPDMA1_Channel0;
DMA_QListTypeDef List_GPDMA1_Channel0;
DMA_HandleTypeDef handle_GPDMA1_Channel0;
void LPUART1_Init(uint32_t baud)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
DMA_NodeConfTypeDef NodeConfig;
__HAL_RCC_LPUART1_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPDMA1_CLK_ENABLE();
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK3;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF8_LPUART1;
GPIO_InitStruct.Pin = GPIO_PIN_2 | GPIO_PIN_3;
HAL_GPIO_Init(GPIOA , &GPIO_InitStruct);
hlpuart1.Instance = LPUART1;
hlpuart1.Init.BaudRate = baud;
hlpuart1.Init.WordLength = UART_WORDLENGTH_8B;
hlpuart1.Init.StopBits = UART_STOPBITS_1;
hlpuart1.Init.Parity = UART_PARITY_NONE;
hlpuart1.Init.Mode = UART_MODE_TX_RX;
hlpuart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
hlpuart1.Init.OverSampling = UART_OVERSAMPLING_16;
hlpuart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
hlpuart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;
hlpuart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
HAL_UART_Init(&hlpuart1);
__HAL_UART_ENABLE_IT(&hlpuart1 , UART_IT_IDLE);
HAL_NVIC_SetPriority(LPUART1_IRQn,1,1);
HAL_NVIC_EnableIRQ(LPUART1_IRQn);
NodeConfig.NodeType = DMA_GPDMA_LINEAR_NODE;
NodeConfig.Init.Request = GPDMA1_REQUEST_LPUART1_RX;
NodeConfig.Init.BlkHWRequest = DMA_BREQ_SINGLE_BURST;
NodeConfig.Init.Direction = DMA_PERIPH_TO_MEMORY;
NodeConfig.Init.SrcInc = DMA_SINC_FIXED;
NodeConfig.Init.DestInc = DMA_DINC_INCREMENTED;
NodeConfig.Init.SrcDataWidth = DMA_SRC_DATAWIDTH_BYTE;
NodeConfig.Init.DestDataWidth = DMA_DEST_DATAWIDTH_BYTE;
NodeConfig.Init.SrcBurstLength = 1;
NodeConfig.Init.DestBurstLength = 1;
NodeConfig.Init.TransferAllocatedPort = DMA_SRC_ALLOCATED_PORT0|DMA_DEST_ALLOCATED_PORT0;
NodeConfig.Init.TransferEventMode = DMA_TCEM_BLOCK_TRANSFER;
NodeConfig.Init.Mode = DMA_NORMAL;
NodeConfig.TriggerConfig.TriggerPolarity = DMA_TRIG_POLARITY_MASKED;
NodeConfig.DataHandlingConfig.DataExchange = DMA_EXCHANGE_NONE;
NodeConfig.DataHandlingConfig.DataAlignment = DMA_DATA_RIGHTALIGN_ZEROPADDED;
HAL_DMAEx_List_BuildNode(&NodeConfig, &Node_GPDMA1_Channel0);
HAL_DMAEx_List_InsertNode(&List_GPDMA1_Channel0, NULL, &Node_GPDMA1_Channel0);
HAL_DMAEx_List_SetCircularMode(&List_GPDMA1_Channel0);
handle_GPDMA1_Channel0.Instance = GPDMA1_Channel0;
handle_GPDMA1_Channel0.InitLinkedList.Priority = DMA_LOW_PRIORITY_LOW_WEIGHT;
handle_GPDMA1_Channel0.InitLinkedList.LinkStepMode = DMA_LSM_FULL_EXECUTION;
handle_GPDMA1_Channel0.InitLinkedList.LinkAllocatedPort = DMA_LINK_ALLOCATED_PORT0;
handle_GPDMA1_Channel0.InitLinkedList.TransferEventMode = DMA_TCEM_BLOCK_TRANSFER;
handle_GPDMA1_Channel0.InitLinkedList.LinkedListMode = DMA_LINKEDLIST_CIRCULAR;
HAL_DMAEx_List_Init(&handle_GPDMA1_Channel0);
HAL_DMAEx_List_LinkQ(&handle_GPDMA1_Channel0, &List_GPDMA1_Channel0);
__HAL_LINKDMA(&hlpuart1, hdmarx, handle_GPDMA1_Channel0);
HAL_DMA_ConfigChannelAttributes(&handle_GPDMA1_Channel0, DMA_CHANNEL_NPRIV);
HAL_NVIC_SetPriority(GPDMA1_Channel0_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(GPDMA1_Channel0_IRQn);
}
void LPUART1_Send_Char(uint8_t ch)
{
while ((LPUART1->ISR & 0X40) == 0);
LPUART1->TDR = (uint8_t)ch;
}
void LPUART1_Send_String(uint8_t * s)
{
uint32_t i;
for(i = 0 ; s != '\0' ; i++)
LPUART1_Send_Char(s);
}
void GPDMA1_Channel0_IRQHandler(void)
{
HAL_DMA_IRQHandler(&handle_GPDMA1_Channel0);
}
uint8_t aRxBuffer[RXBUFFERSIZE];
void LPUART1_IRQHandler(void)
{
// int temp;
if(LPUART1->ISR & UART_FLAG_IDLE)
{
__HAL_UART_CLEAR_IDLEFLAG(&hlpuart1);
printf("LPUART1_IRQHandler. %d %s\n" , GPDMA1_Channel0->CBR1 , aRxBuffer);
HAL_UART_DMAStop(&hlpuart1);
HAL_UART_Receive_DMA(&hlpuart1, (uint8_t *)aRxBuffer, RXBUFFERSIZE);
// rx1_len = BUFFERSIZE - DMA1_Channel5->CNDTR;
// uart1_recv_end_flag = 1;
}
}

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在ST的新系列里面，有个特殊机制，使用任何形式的DMA通信必须要打开DMA中断，这个在F103系列是不需要的，是F4以及之后的大部分系列都需要，另外，在F4之后的系列中，对于外设要用的DMA，可以自由配置通道Channel（流Stream/节点Node）等，其实是一个东西，就是DMA通道的意思，不同系列的名称不同，只有F103和F4系列的特定外设是绑定在特定DMA通道的。像本帖子，就把LPUART1的RX功能设置在在GPDMA的通道0（后续还把SPI1的TX功能设置在GPDMA的通道1）。