请给出IO中断模拟IIC从机GD32F130的例程

以下是IO中断模拟IIC从机GD32F130的例程，请参考：

#include "gd32f1x0.h"
#include "stdio.h"
#include "systick.h"
#define I2C2_SCL_PIN                         GPIO_PIN_6                  /*!< GPIO pin of the I2C clock */
#define I2C2_SCL_GPIO_PORT                   GPIOB                      /*!< GPIO port of the I2C clock */
#define I2C2_SDA_PIN                         GPIO_PIN_7                  /*!< GPIO pin of the I2C data */
#define I2C2_SDA_GPIO_PORT                   GPIOB                      /*!< GPIO port of the I2C data */
#define I2C2_RCC_CLK_ENABLE()                rcu_periph_clock_enable(RCU_GPIOB) /*!< Enable GPIOB clock */
#define I2C2_RCC_CLK_DISABLE()               rcu_periph_clock_disable(RCU_GPIOB) /*!< Disable GPIOB clock */
#define I2C2_SCL_HIGH()                      gpio_bit_set(I2C2_SCL_GPIO_PORT, I2C2_SCL_PIN) /*!< Set GPIOB pin 6 */
#define I2C2_SCL_LOW()                       gpio_bit_reset(I2C2_SCL_GPIO_PORT, I2C2_SCL_PIN) /*!< Reset GPIOB pin 6 */
#define I2C2_SDA_HIGH()                      gpio_bit_set(I2C2_SDA_GPIO_PORT, I2C2_SDA_PIN) /*!< Set GPIOB pin 7 */
#define I2C2_SDA_LOW()                       gpio_bit_reset(I2C2_SDA_GPIO_PORT, I2C2_SDA_PIN) /*!< Reset GPIOB pin 7 */
#define I2C2_SDA_READ()                      gpio_input_bit_get(I2C2_SDA_GPIO_PORT, I2C2_SDA_PIN) /*!< Read GPIOB pin 7 */

void delay(uint32_t count)
{
    uint32_t index = 0;
    for(index = count; index != 0; index--)
    {
    }
}

void I2C2_GPIO_Config(void)
{
    rcu_periph_clock_enable(RCU_AF);
    rcu_periph_clock_enable(RCU_GPIOB);
    /*configure GPIO pin of I2C2*/
    gpio_init(I2C2_SCL_GPIO_PORT, GPIO_MODE_OUT_OD, GPIO_OSPEED_50MHZ, I2C2_SCL_PIN);
    gpio_init(I2C2_SDA_GPIO_PORT, GPIO_MODE_OUT_OD, GPIO_OSPEED_50MHZ, I2C2_SDA_PIN);
    /*configure I2C2 as a master*/
    gpio_init(I2C2_SCL_GPIO_PORT, GPIO_MODE_AF_OD, GPIO_OSPEED_50MHZ, I2C2_SCL_PIN);
    gpio_init(I2C2_SDA_GPIO_PORT, GPIO_MODE_AF_OD, GPIO_OSPEED_50MHZ, I2C2_SDA_PIN);
    gpio_pin_remap_config(GPIO_SPI2_REMAP,I2C2_MAP);
}

void I2C2_Start(void)
{
    I2C2_SDA_HIGH();
    I2C2_SCL_HIGH();
    delay(5);
    I2C2_SDA_LOW();
    delay(5);
    I2C2_SCL_LOW();
}

void I2C2_Stop(void)
{
    I2C2_SDA_LOW();
    I2C2_SCL_HIGH();
    delay(5);
    I2C2_SDA_HIGH();
    delay(5);
}

uint8_t I2C2_WaitAck(void)
{
    uint8_t ucErrTime = 0;
    I2C2_SDA_HIGH();
    delay(1);
    I2C2_SCL_HIGH();
    delay(1);
    while(I2C2_SDA_READ())
    {
        ucErrTime++;
        if(ucErrTime > 50)
        {
            I2C2_Stop();
            return 1;
        }
        delay(1);
    }
    I2C2_SCL_LOW();
    return 0;
}

void I2C2_Ack(void)
{
    I2C2_SCL_LOW();
    I2C2_SDA_LOW();
    delay(2);
    I2C2_SCL_HIGH();
    delay(2);
    I2C2_SCL_LOW();
}

void I2C2_NAck(void)
{
    I2C2_SCL_LOW();
    I2C2_SDA_HIGH();
    delay(2);
    I2C2_SCL_HIGH();
    delay(2);
    I2C2_SCL_LOW();
}

void I2C2_SendByte(uint8_t ucData)
{
    uint8_t ucCount = 0;
    for(ucCount = 0; ucCount < 8; ucCount++)
    {
        if(ucData & 0x80)
            I2C2_SDA_HIGH();
        else
            I2C2_SDA_LOW();
        ucData <<= 1;
        delay(2);
        I2C2_SCL_HIGH(); 
        delay(2);
        I2C2_SCL_LOW();
    }
}

uint8_t I2C2_ReadByte(uint8_t ucAck)
{
    uint8_t ucCount = 0, ucData = 0;
    I2C2_SDA_HIGH();
    for(ucCount = 0; ucCount < 8; ucCount++)
    {
        ucData <<= 1;
        I2C2_SCL_LOW();
        delay(2);
        I2C2_SCL_HIGH();
        delay(2);
        if(I2C2_SDA_READ())
            ucData++;
    }
    if(!ucAck)
       I2C2_NAck();
    else
       I2C2_Ack();
    return ucData;
}

void GD32_I2C2_Init(void)
{
    I2C2_GPIO_Config();
}

uint8_t GD32_I2C2_ReadByte(uint8_t ucAddr, uint8_t ucReg)
{
    uint8_t ucData = 0;
    I2C2_Start();
    I2C2_SendByte(ucAddr << 1 | 0);
    if(I2C2_WaitAck())
    {
        I2C2_Stop();
        return 0;
    }
    I2C2_SendByte(ucReg);
    I2C2_WaitAck();
    I2C2_Start();
    I2C2_SendByte(ucAddr << 1 | 1);
    I2C2_WaitAck();
    ucData = I2C2_ReadByte(0);
    I2C2_Stop();
    return ucData;
}

void GD32_I2C2_WriteByte(uint8_t ucAddr, uint8_t ucReg, uint8_t ucValue)
{
    I2C2_Start();
    I2C2_SendByte(ucAddr << 1 | 0);
    if(I2C2_WaitAck())
    {
        I2C2_Stop();
        return;
    }
    I2C2_SendByte(ucReg);
    I2C2_WaitAck();
    I2C2_SendByte(ucValue);
    I2C2_WaitAck();
    I2C2_Stop();
}

int main(void)
{
    uint8_t ucData = 0;
    GD32_I2C2_Init();
    while(1)
    {
        ucData = GD32_I2C2_ReadByte(0x68, 0x75);
        printf("WHO_AM_I is %X \r\n", ucData);
        delay_1ms(1000);
    }
}