usart、uart、i2c、spi代码

以下是USART、UART、I2C和SPI的基本代码框架，供您参考：

USART:

#include <stdio.h>
#include <stm32f4xx.h>

USART_InitTypeDef USART_InitStruct;

void USART_Config()
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    USART_InitStruct.USART_BaudRate = 115200;
    USART_InitStruct.USART_WordLength = USART_WordLength_8b;
    USART_InitStruct.USART_StopBits = USART_StopBits_1;
    USART_InitStruct.USART_Parity = USART_Parity_No;
    USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;

    USART_Init(USART2, &USART_InitStruct);
    USART_Cmd(USART2, ENABLE);
}

int main(void)
{
    USART_Config();

    while (1)
    {
        // 发送数据
        USART_SendData(USART2, 'a');

        // 接收数据
        if (USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET)
        {
            char data = USART_ReceiveData(USART2);
        }
    }
}

UART:

#include <stdio.h>
#include <stm32f4xx.h>

UART_HandleTypeDef UART_InitStruct;

void UART_Config()
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    UART_InitStruct.Instance = USART1;
    UART_InitStruct.Init.BaudRate = 115200;
    UART_InitStruct.Init.WordLength = UART_WORDLENGTH_8B;
    UART_InitStruct.Init.StopBits = UART_STOPBITS_1;
    UART_InitStruct.Init.Parity = UART_PARITY_NONE;
    UART_InitStruct.Init.Mode = UART_MODE_TX_RX;
    UART_InitStruct.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    UART_InitStruct.Init.OverSampling = UART_OVERSAMPLING_16;

    HAL_UART_Init(&UART_InitStruct);
}

int main(void)
{
    UART_Config();

    while (1)
    {
        // 发送数据
        uint8_t data = 'a';
        HAL_UART_Transmit(&UART_InitStruct, &data, 1, 100);

        // 接收数据
        uint8_t data_recv;
        HAL_UART_Receive(&UART_InitStruct, &data_recv, 1, 100);
    }
}

I2C:

#include <stdio.h>
#include <stm32f4xx.h>

I2C_HandleTypeDef I2C_InitStruct;

void I2C_Config()
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_OD;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOB, &GPIO_InitStruct);

    GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);

    I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStruct.I2C_OwnAddress1 = 0x00;
    I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStruct.I2C_ClockSpeed = 100000;

    HAL_I2C_Init(&I2C_InitStruct);
}

int main(void)
{
    I2C_Config();

    while (1)
    {
        // 写入数据
        uint8_t data = 'a';
        HAL_I2C_Master_Transmit(&I2C_InitStruct, 0x50, &data, 1, 100);

        // 读取数据
        uint8_t data_recv;
        HAL_I2C_Master_Receive(&I2C_InitStruct, 0x50, &data_recv, 1, 100);
    }
}

SPI:

#include <stdio.h>
#include <stm32f4xx.h>

SPI_HandleTypeDef SPI_InitStruct;

void SPI_Config()
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);

    SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
    SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStruct.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
    SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStruct.SPI_CRCPolynomial = 7;

    HAL_SPI_Init(&SPI_InitStruct);
}

int main(void)
{
    SPI_Config();

    while (1)
    {
        // 发送数据
        uint8_t data = 'a';
        HAL_SPI_Transmit(&SPI_InitStruct, &data, 1, 100);

        // 接收数据
        uint8_t data_recv;
        HAL_SPI_Receive(&SPI_InitStruct, &data_recv, 1, 100);
    }
}