用C语言写一个STM32硬件i2c程序

下面是一个简单的STM32硬件I2C程序，使用了STM32F103C8T6开发板和Keil MDK编译器：

#include "stm32f10x.h"

#define I2C1_OWN_ADDR   0xA0
#define I2C_SLAVE_ADDR  0x50

void I2C1_init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    I2C_InitTypeDef I2C_InitStruct;
    
    // Enable clock for GPIOB and I2C1
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    
    // Configure PB6 and PB7 as I2C1_SCL and I2C1_SDA
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_Init(GPIOB, &GPIO_InitStruct);
    
    // Configure I2C1
    I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStruct.I2C_OwnAddress1 = I2C1_OWN_ADDR;
    I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStruct.I2C_ClockSpeed = 100000;
    I2C_Init(I2C1, &I2C_InitStruct);
    
    // Enable I2C1
    I2C_Cmd(I2C1, ENABLE);
}

void I2C1_start(void)
{
    // Send start condition
    I2C_GenerateSTART(I2C1, ENABLE);
    
    // Wait until start condition is sent
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
}

void I2C1_stop(void)
{
    // Send stop condition
    I2C_GenerateSTOP(I2C1, ENABLE);
    
    // Wait until stop condition is sent
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF));
}

void I2C1_write(uint8_t data)
{
    // Send data byte
    I2C_SendData(I2C1, data);
    
    // Wait until data byte is sent
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
}

uint8_t I2C1_read_ack(void)
{
    // Enable ACK after receiving data byte
    I2C_AcknowledgeConfig(I2C1, ENABLE);
    
    // Wait until data byte is received
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    
    // Read data byte
    uint8_t data = I2C_ReceiveData(I2C1);
    
    return data;
}

uint8_t I2C1_read_nack(void)
{
    // Disable ACK after receiving last data byte
    I2C_AcknowledgeConfig(I2C1, DISABLE);
    
    // Wait until data byte is received
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    
    // Read data byte
    uint8_t data = I2C_ReceiveData(I2C1);
    
    return data;
}

int main(void)
{
    uint8_t data[] = "Hello world!";
    uint8_t buffer[50];
    
    // Initialize I2C1
    I2C1_init();
    
    // Send start condition
    I2C1_start();
    
    // Send slave address and write bit
    I2C1_write(I2C_SLAVE_ADDR << 1 | 0);
    
    // Send data
    for (int i = 0; i < sizeof(data); i++) {
        I2C1_write(data[i]);
    }
    
    // Send stop condition
    I2C1_stop();
    
    // Wait for a while
    for (int i = 0; i < 1000000; i++);
    
    // Send start condition
    I2C1_start();
    
    // Send slave address and read bit
    I2C1_write(I2C_SLAVE_ADDR << 1 | 1);
    
    // Read data
    for (int i = 0; i < sizeof(data) - 1; i++) {
        buffer[i] = I2C1_read_ack();
    }
    
    // Read last data byte with NACK
    buffer[sizeof(data) - 1] = I2C1_read_nack();
    
    // Send stop condition
    I2C1_stop();
    
    // Print received data
    printf("%s", buffer);
    
    while (1);
}

该程序用于向I2C从设备发送"Hello world!"字符串，然后从该设备读取相同的字符串并将其打印到串口。