stm32spi通信例程

以下是一个简单的STM32 SPI通信例程，用于在STM32和外部设备之间进行SPI通信。

首先，需要包含以下头文件：

#include "stm32f10x.h"
#include "stm32f10x_spi.h"
#include "stm32f10x_gpio.h"

然后，需要定义SPI的GPIO引脚和SPI的配置参数：

#define SPI_PORT_SPI1       GPIOA
#define SPI_CS_PIN          GPIO_Pin_4
#define SPI_SCK_PIN         GPIO_Pin_5
#define SPI_MISO_PIN        GPIO_Pin_6
#define SPI_MOSI_PIN        GPIO_Pin_7
#define SPI_SPEED           SPI_BaudRatePrescaler_2
#define SPI_MODE            SPI_Mode_Master
#define SPI_DIRECTION       SPI_Direction_2Lines_FullDuplex
#define SPI_DATA_SIZE       SPI_DataSize_8b
#define SPI_FIRST_BIT       SPI_FirstBit_MSB

接下来，需要进行SPI的初始化：

void SPI_Init(void)
{
    SPI_InitTypeDef SPI_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    // Enable SPI1 and GPIOA clocks
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA, ENABLE);

    // Configure SPI1 pins: SCK, MISO and MOSI
    GPIO_InitStructure.GPIO_Pin = SPI_SCK_PIN | SPI_MISO_PIN | SPI_MOSI_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(SPI_PORT_SPI1, &GPIO_InitStructure);

    // Configure SPI1 CS pin
    GPIO_InitStructure.GPIO_Pin = SPI_CS_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(SPI_PORT_SPI1, &GPIO_InitStructure);

    // Configure SPI1
    SPI_InitStructure.SPI_Direction = SPI_DIRECTION;
    SPI_InitStructure.SPI_Mode = SPI_MODE;
    SPI_InitStructure.SPI_DataSize = SPI_DATA_SIZE;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_SPEED;
    SPI_InitStructure.SPI_FirstBit = SPI_FIRST_BIT;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init(SPI1, &SPI_InitStructure);

    // Enable SPI1
    SPI_Cmd(SPI1, ENABLE);
}

在SPI初始化之后，可以使用以下函数来发送和接收SPI数据：

uint8_t SPI_Transfer(uint8_t data)
{
    // Wait until SPI1 is ready to send data
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);

    // Send data
    SPI_I2S_SendData(SPI1, data);

    // Wait until data is received
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);

    // Receive data
    return SPI_I2S_ReceiveData(SPI1);
}

最后，可以使用以下代码来测试SPI通信：

int main(void)
{
    uint8_t data = 0x55;

    // Initialize SPI
    SPI_Init();

    // Select SPI chip
    GPIO_ResetBits(SPI_PORT_SPI1, SPI_CS_PIN);

    // Send data
    SPI_Transfer(data);

    // Deselect SPI chip
    GPIO_SetBits(SPI_PORT_SPI1, SPI_CS_PIN);

    while (1);
}

在该例程中，向SPI发送一个字节的数据，并通过SPI收到响应。在实际应用中，可能需要根据具体的需求进行修改和扩展。