#ifdef __cplusplus
extern "C" {
#endif 

#include "i2c.h"

static void I2C_delay()
{	
    volatile int i = 17;
    while (i)
        i--;
}

static int HC_I2C_Start()
{
    HC_SDA_H;
    HC_SCL_H;
    I2C_delay();
    if (!SDA_read)
        return 0;
    HC_SDA_L;
    I2C_delay();
    if (HC_SDA_read)
        return 0;
    HC_SDA_L;
    I2C_delay();
    return 1;
}

static void HC_I2C_Stop()
{
    HC_SCL_L;
    I2C_delay();
    HC_SDA_L;
    I2C_delay();
    HC_SCL_H;
    I2C_delay();
    HC_SDA_H;
    I2C_delay();
} 
  

static void HC_I2C_NoAck()
{	
    HC_SCL_L;
    I2C_delay();
    HC_SDA_H;
    I2C_delay();
    HC_SCL_H;
    I2C_delay();
    HC_SCL_L;
    I2C_delay();
} 

static int HC_I2C_WaitAck() 	
{
    HC_SCL_L;
    I2C_delay();
    HC_SDA_H;
    I2C_delay();
    HC_SCL_H;
    I2C_delay();
    if (HC_SDA_read) {
        HC_SCL_L;
        return 0;
    }
    HC_SCL_L;
    return 1;
}

static void HC_I2C_SendByte(uint8_t b) 
{
    uint8_t i = 8;
    while (i--) {
        HC_SCL_L;
        I2C_delay();
        if (b & 0x80)
            HC_SDA_H;
        else
            HC_SDA_L;
        b <<= 1;
        I2C_delay();
        HC_SCL_H;
        I2C_delay();
    }
    HC_SCL_L;
}  

static uint8_t HC_I2C_ReadByte()  
{ 
    uint8_t i = 8;
    uint8_t byte = 0;

    HC_SDA_H;
    while (i--) {
        byte <<= 1;
        HC_SCL_L;
        I2C_delay();
        HC_SCL_H;
        I2C_delay();
        if (HC_SDA_read) {
            byte |= 0x01;
        }
    }
    HC_SCL_L;
    return byte;
} 

void HC_I2C_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    // 使能GPIOB时钟
    __HAL_RCC_GPIOB_CLK_ENABLE(); 
 
    GPIO_InitStruct.Pin = GPIO_PIN_0;             // SCL
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;   // 开漏输出
    GPIO_InitStruct.Pull = GPIO_PULLUP;           // 使用上拉
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
    GPIO_InitStruct.Pin = GPIO_PIN_1;             // SDA
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;   // 开漏输出
    GPIO_InitStruct.Pull = GPIO_PULLUP;           // 使用上拉
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}

void HC_I2C_Write()
{
    HC_I2C_Start();
    HC_I2C_SendByte(0xAE);
    HC_I2C_WaitAck();
    HC_I2C_SendByte(0x01); 
    HC_I2C_WaitAck();
    HC_I2C_Stop();
}

int HC_I2C_Read()
{
   unsigned int BYTE_H=0, BYTE_M=0, BYTE_L=0;
   float distance=0;//测距距离
	 //读数据-地址为0xAF
    if (!HC_I2C_Start())
        return 0;
    HC_I2C_SendByte(0xAF);
    if (!HC_I2C_WaitAck()) {
       HC_I2C_Stop();
			 return 0;
    }
	  BYTE_H=HC_I2C_ReadByte();//读数据
		HC_I2C_WaitAck();
		BYTE_M=HC_I2C_ReadByte();//读数据
		HC_I2C_WaitAck();
		BYTE_L=HC_I2C_ReadByte();//读数据
		HC_I2C_NoAck();  
		HC_I2C_Stop(); 
		distance=((BYTE_H*65536)+(BYTE_M*256)+BYTE_L)/1000.0f;//单位mm
		return distance;
}