串口发送

重写fputc函数

/*
优点
	直接使用printf函数，发送数据长度无限制，不需要额外的数组空间
缺点
	只能对应一个串口，暂时没想到解决方案
*/

//头文件中要包含 stdio.h 然后就可以正常使用printf了
int fputc(int ch ,FILE *F)
{
	HAL_UART_Transmit(&huart2, (uint8_t *)&ch, 1, HAL_MAX_DELAY); //按照配置自行修改huart2
	return ch;
}

宏定义实现

/*
优点
	使用不同的定义可以对应不同的串口
缺点
	需要创建额外的数据空间，发送数据长度有限制
*/
//首先要定义 uint8_t u_buf[256]; 这个数组
#define U1_printf(...) HAL_UART_Transmit(&huart1,(uint8_t *)u_buf,sprintf((char*)u_buf,__VA_ARGS__),HAL_MAX_DELAY)
//按照配置自行修改huart1

阻塞与非阻塞发送

阻塞发送：HAL_UART_Transmit

发送数据全,不会漏发
需要占用cpu

非阻塞发送 ：HAL_UART_Transmit_DMA HAL_UART_Transmit_IT

发送需要时间，可能会漏发，可加延时
不占用cpu资源

串口接收

三种接收方式

//需要先定义一个数组 pData 存放接收的数据
HAL_StatusTypeDef HAL_UART_Receive(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)
HAL_StatusTypeDef HAL_UART_Receive_DMA(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) //接收完毕回调函数

CRC校验实现数据纠正

由于接收的数据是定长的，会出现数据错位。可以利用CRC校验，当校验不通过时，直接重启接收，使得数据可以纠正过来。

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) //接收完毕回调函数
{
    if(huart->Instrance == USART1)
    {
        if(cal_crc_table(rx_buf,4) == rx_buf[4])  //cal_crc_table 传入参数为数据数组地址，有效数据长度
            U1_printf("CRC OK!!!\R\N");
        else
        {
            U1_printf("CRC ERROR!!!\R\N");
            /************重启串口DMA接收****************/
            HAL_UART_DMAStop(&huart1);
            HAL_Delay(3);
            HAL_UART_Receive_DMA(&huart1,rxbuf,5);
        }
    }
}

CRC校验代码

/*
参考：https://blog.csdn.net/zjli321/article/details/52998468
移植说明
	移植到 usart.c 文件
	usart.h 文件中添加 extern static const unsigned char crc_table[] 声明
	usart.h 文件中添加 unsigned char cal_crc_table(unsigned char *ptr, unsigned char len) 声明
*/
static const unsigned char crc_table[] =
{
    0x00,0x31,0x62,0x53,0xc4,0xf5,0xa6,0x97,0xb9,0x88,0xdb,0xea,0x7d,0x4c,0x1f,0x2e,
    0x43,0x72,0x21,0x10,0x87,0xb6,0xe5,0xd4,0xfa,0xcb,0x98,0xa9,0x3e,0x0f,0x5c,0x6d,
    0x86,0xb7,0xe4,0xd5,0x42,0x73,0x20,0x11,0x3f,0x0e,0x5d,0x6c,0xfb,0xca,0x99,0xa8,
    0xc5,0xf4,0xa7,0x96,0x01,0x30,0x63,0x52,0x7c,0x4d,0x1e,0x2f,0xb8,0x89,0xda,0xeb,
    0x3d,0x0c,0x5f,0x6e,0xf9,0xc8,0x9b,0xaa,0x84,0xb5,0xe6,0xd7,0x40,0x71,0x22,0x13,
    0x7e,0x4f,0x1c,0x2d,0xba,0x8b,0xd8,0xe9,0xc7,0xf6,0xa5,0x94,0x03,0x32,0x61,0x50,
    0xbb,0x8a,0xd9,0xe8,0x7f,0x4e,0x1d,0x2c,0x02,0x33,0x60,0x51,0xc6,0xf7,0xa4,0x95,
    0xf8,0xc9,0x9a,0xab,0x3c,0x0d,0x5e,0x6f,0x41,0x70,0x23,0x12,0x85,0xb4,0xe7,0xd6,
    0x7a,0x4b,0x18,0x29,0xbe,0x8f,0xdc,0xed,0xc3,0xf2,0xa1,0x90,0x07,0x36,0x65,0x54,
    0x39,0x08,0x5b,0x6a,0xfd,0xcc,0x9f,0xae,0x80,0xb1,0xe2,0xd3,0x44,0x75,0x26,0x17,
    0xfc,0xcd,0x9e,0xaf,0x38,0x09,0x5a,0x6b,0x45,0x74,0x27,0x16,0x81,0xb0,0xe3,0xd2,
    0xbf,0x8e,0xdd,0xec,0x7b,0x4a,0x19,0x28,0x06,0x37,0x64,0x55,0xc2,0xf3,0xa0,0x91,
    0x47,0x76,0x25,0x14,0x83,0xb2,0xe1,0xd0,0xfe,0xcf,0x9c,0xad,0x3a,0x0b,0x58,0x69,
    0x04,0x35,0x66,0x57,0xc0,0xf1,0xa2,0x93,0xbd,0x8c,0xdf,0xee,0x79,0x48,0x1b,0x2a,
    0xc1,0xf0,0xa3,0x92,0x05,0x34,0x67,0x56,0x78,0x49,0x1a,0x2b,0xbc,0x8d,0xde,0xef,
    0x82,0xb3,0xe0,0xd1,0x46,0x77,0x24,0x15,0x3b,0x0a,0x59,0x68,0xff,0xce,0x9d,0xac
};

unsigned char cal_crc_table(unsigned char *ptr, unsigned char len) 
{
    unsigned char  crc = 0x00;

    while (len--)
    {
        crc = crc_table[crc ^ *ptr++];
    }
    return (crc);
}