STM32F103C8T6串口1的DMA，如何实现上位机串口助手发送指令到单片机 ?需要用到定时中断吗?

在使用DMA实现串口通信时，定时中断并不是必须的，但是需要注意一些细节：

1. 首先需要配置串口1和DMA的相关寄存器，使它们能够正常工作。具体步骤如下：

- 配置串口1的波特率、数据位、停止位等参数；
- 使能串口1和DMA时钟；
- 配置DMA通道，指定源地址为串口1的数据寄存器（USART_DR），目的地址为接收缓冲区，传输数据长度为1个字节；
- 使能DMA通道。

2. 然后在主程序中，需要开启串口1的接收中断，并在中断服务函数中处理接收到的数据。具体步骤如下：

- 开启串口1的接收中断；
- 在中断服务函数中，判断接收到的数据是否是指令结束符，如果是，则将接收缓冲区的数据拷贝到一个新的缓冲区中，并清空接收缓冲区；
- 在主程序中，根据接收到的指令进行相应的处理。

下面是一个简单的示例代码，供参考：

#include "stm32f10x.h"

#define BUFFER_SIZE 64

uint8_t rxBuffer[BUFFER_SIZE];
uint8_t cmdBuffer[BUFFER_SIZE];
uint8_t rxIndex = 0;
uint8_t cmdIndex = 0;

void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        rxBuffer[rxIndex++] = USART_ReceiveData(USART1);
        if (rxBuffer[rxIndex - 1] == '\n' || rxIndex >= BUFFER_SIZE)
        {
            memcpy(cmdBuffer, rxBuffer, rxIndex);
            cmdIndex = rxIndex;
            rxIndex = 0;
            USART_ITConfig(USART1, USART_IT_RXNE, DISABLE);
        }
    }
}

void DMA1_Channel4_IRQHandler(void)
{
    if (DMA_GetITStatus(DMA1_IT_TC4) != RESET)
    {
        DMA_ClearITPendingBit(DMA1_IT_TC4);
        DMA_Cmd(DMA1_Channel4, DISABLE);
        USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);
        USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
    }
}

int main(void)
{
    USART_InitTypeDef USART_InitStructure;
    DMA_InitTypeDef DMA_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

    USART_InitStructure.USART_BaudRate = 115200;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)rxBuffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_BufferSize = 1;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel5, &DMA_InitStructure);

    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    USART_Cmd(USART1, ENABLE);
    USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);

    while (1)
    {
        // 处理接收到的指令
        if (cmdIndex > 0)
        {
            // do something
            cmdIndex = 0;
        }
    }
}