用C语言代码实现IIC

IIC是一种串行通信协议，可以通过两根线（SDA和SCL）在多个设备之间进行数据传输。以下是一个使用C语言实现IIC协议的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>

// I2C port configuration
#define I2C_PORT GPIOB
#define I2C_SCL_PIN GPIO_PIN_6
#define I2C_SDA_PIN GPIO_PIN_7

// I2C timing configuration
#define I2C_TIMING 0x0070268E

// I2C commands
#define I2C_READ 1
#define I2C_WRITE 0

// I2C ack/nack responses
#define I2C_ACK 0
#define I2C_NACK 1

// I2C timeout
#define I2C_TIMEOUT 1000

// I2C delay
#define I2C_DELAY_US 2

// I2C initialization function
void i2c_init(void) {
    // Enable GPIO and I2C clocks
    __HAL_RCC_GPIOB_CLK_ENABLE();
    __HAL_RCC_I2C1_CLK_ENABLE();

    // Configure GPIO pins
    GPIO_InitTypeDef GPIO_InitStruct = {0};
    GPIO_InitStruct.Pin = I2C_SCL_PIN | I2C_SDA_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF4_I2C1;
    HAL_GPIO_Init(I2C_PORT, &GPIO_InitStruct);

    // Configure I2C peripheral
    I2C_HandleTypeDef I2cHandle = {0};
    I2cHandle.Instance = I2C1;
    I2cHandle.Init.Timing = I2C_TIMING;
    I2cHandle.Init.OwnAddress1 = 0;
    I2cHandle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
    I2cHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
    I2cHandle.Init.OwnAddress2 = 0;
    I2cHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
    I2cHandle.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
    HAL_I2C_Init(&I2cHandle);
}

// I2C start condition function
bool i2c_start(I2C_HandleTypeDef *hi2c, uint8_t address, uint8_t direction) {
    // Enable I2C peripheral
    __HAL_I2C_ENABLE(hi2c);

    // Wait for I2C ready
    uint32_t timeout = 0;
    while (hi2c->State != HAL_I2C_STATE_READY) {
        if (++timeout >= I2C_TIMEOUT) {
            return false;
        }
        HAL_Delay(I2C_DELAY_US);
    }

    // Generate start condition
    if (HAL_I2C_Master_Transmit(hi2c, (address << 1) | direction, 0, I2C_TIMEOUT) != HAL_OK) {
        return false;
    }

    // Wait for I2C ready
    timeout = 0;
    while (hi2c->State != HAL_I2C_STATE_READY) {
        if (++timeout >= I2C_TIMEOUT) {
            return false;
        }
        HAL_Delay(I2C_DELAY_US);
    }

    return true;
}

// I2C stop condition function
void i2c_stop(I2C_HandleTypeDef *hi2c) {
    // Generate stop condition
    HAL_I2C_Stop(hi2c);

    // Disable I2C peripheral
    __HAL_I2C_DISABLE(hi2c);
}

// I2C send byte function
bool i2c_send_byte(I2C_HandleTypeDef *hi2c, uint8_t data) {
    // Transmit byte
    if (HAL_I2C_Master_Transmit(hi2c, &data, 1, I2C_TIMEOUT) != HAL_OK) {
        return false;
    }

    // Wait for I2C ready
    uint32_t timeout = 0;
    while (hi2c->State != HAL_I2C_STATE_READY) {
        if (++timeout >= I2C_TIMEOUT) {
            return false;
        }
        HAL_Delay(I2C_DELAY_US);
    }

    return true;
}

// I2C receive byte function
bool i2c_receive_byte(I2C_HandleTypeDef *hi2c, uint8_t *data, bool ack) {
    // Receive byte
    if (HAL_I2C_Master_Receive(hi2c, data, 1, I2C_TIMEOUT) != HAL_OK) {
        return false;
    }

    // Send ack/nack response
    if (ack) {
        if (HAL_I2C_Master_Transmit(hi2c, &I2C_ACK, 1, I2C_TIMEOUT) != HAL_OK) {
            return false;
        }
    } else {
        if (HAL_I2C_Master_Transmit(hi2c, &I2C_NACK, 1, I2C_TIMEOUT) != HAL_OK) {
            return false;
        }
    }

    // Wait for I2C ready
    uint32_t timeout = 0;
    while (hi2c->State != HAL_I2C_STATE_READY) {
        if (++timeout >= I2C_TIMEOUT) {
            return false;
        }
        HAL_Delay(I2C_DELAY_US);
    }

    return true;
}

使用以上的代码可以实现基本的IIC通信功能。需要注意的是，以上代码只是IIC通信协议的一部分实现，具体的数据传输需要结合具体的应用场景进行编写。