0103_APP/Hardware/I2C.c

#include "I2C.h"
#include "timeout.h"

void delay_us(uint32_t nUs)
{
    uint32_t i=0,j=0;
    for(i=0;i<nUs;i++){
        for(j=0;j<9;j++){
            ;
        }
    }
}

void delay_ms(uint16_t nms)
{
    delay_us(nms*1000);
}

/*-----------------------------------------------
 *  I2C 初始化
 * ----------------------------------------------*/
void i2c_init(void)
{
    rcu_periph_clock_enable(RCU_GPIOB);/* enable GPIO clock */
    rcu_periph_clock_enable(RCU_GPIOE);/* enable GPIO clock */

    gpio_bit_set(IIC_WP_PORT,IIC_WP_PIN); /* 写保护启用 */
    gpio_init(IIC_WP_PORT, GPIO_MODE_OUT_PP, GPIO_OSPEED_2MHZ, IIC_WP_PIN);/*写使能 PE15 */

    gpio_bit_set(IIC_SCL_PORT,IIC_SCL_PIN); /* 时钟信号 置高 */
    gpio_init(IIC_SCL_PORT, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ, IIC_SCL_PIN);/* SCL 时钟信号 PB6 */

    gpio_bit_set(IIC_SDA_PORT,IIC_SDA_PIN); /* 数据信号 置高 */
    gpio_init(IIC_SDA_PORT, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ, IIC_SDA_PIN);/* DA 数据信号 PB7 */
}
/*--------------------------------------------------
 * I2C的起始信号
 * -------------------------------------------------*/
void i2c_start(void)
{
    SDA_OUT();
    IIC_SDA(1);//IIC_SDA = 1;
    IIC_SCL(1);//IIC_SCL = 1;
    delay_us(4);
    IIC_SDA(0);//IIC_SDA = 0;//START:when CLK is high,DATA change form high to low
    delay_us(4);
    IIC_SCL(0);//IIC_SCL = 0;
}
/*------------------------------------------------------
 *  I2C的停止信号
 * -----------------------------------------------------*/
void i2c_stop(void)
{
    SDA_OUT();
    IIC_SDA(0);//IIC_SDA = 0;
    IIC_SCL(0);//IIC_SCL = 0;
    delay_us(4);
    IIC_SCL(1);//IIC_SCL = 1;
	  delay_us(4);
    IIC_SDA(1);//IIC_SDA = 1;
    delay_us(4);
}
/*-----------------------------------------------------
 * I2C 等待信号应答
 * 返回： 0：接收应答成功
 *       1：接收应答失败
 * ---------------------------------------------------*/
uint8_t i2c_wait_ack(void)
{
    uint8_t ucErrTime=0;
    SDA_IN();  // SDA 配置成输入
    IIC_SDA(1);//IIC_SDA=1;
    delay_us(1);
    IIC_SCL(1);//IIC_SCL=1;
    delay_us(1);
    while(READ_SDA)
    {
        ucErrTime++;
        if(ucErrTime>250)
        {
        i2c_stop();
        return 1;
        }
    }
    IIC_SCL(0);//IIC_SCL=0;
    return 0;
}
/*-----------------------------------------------------
 *  I2C 产生应答
 * ---------------------------------------------------*/
void i2c_Ack(void)
{
    IIC_SCL(0);//IIC_SCL = 0;
    SDA_OUT();
    IIC_SDA(0);//IIC_SDA = 0;
    delay_us(4);
    IIC_SCL(1);//IIC_SCL = 1;
    delay_us(2);
    IIC_SCL(0);//IIC_SCL = 0;
}
/*-----------------------------------------------------
 *  I2C 没有产生应答
 * ---------------------------------------------------*/
void i2c_NAck(void)
{
    IIC_SCL(0);//IIC_SCL = 0;
    SDA_OUT();
    IIC_SDA(1);//IIC_SDA = 1;
    delay_us(4);
    IIC_SCL(1);//IIC_SCL = 1;
    delay_us(2);
    IIC_SCL(0);//IIC_SCL = 0;
}
/*-----------------------------------------------------
 *  IIC 发送一个字节
 *  返回 1：有应答  0：无应答
 * ---------------------------------------------------*/
void i2c_send_byte(uint8_t txd)
{
  uint8_t t;
  IIC_SCL(0);//IIC_SCL=0;// 电平置低，开始传输数据
  SDA_OUT();
  for(t=0;t<8;t++)
  {
   // IIC_SDA=(txd&0x80)>>7;
    if((txd&0x80)>>7) IIC_SDA(1);
    else IIC_SDA(0);
    txd<<=1;
    delay_us(4);   //
    IIC_SCL(1);//IIC_SCL=1;
    delay_us(2);
    IIC_SCL(0);//IIC_SCL=0;
    delay_us(2);

  }
}
/*-------------------------------------------------
 * 读1个字节，ack=1时，发送ACK，ack=0，发送nACK
 * -------------------------------------------------*/
uint8_t i2c_read_byte(uint8_t ack)
{
    uint8_t i,receive=0;
    SDA_IN();//SDA设置为输入
    for(i=0;i<8;i++ )
    {
        IIC_SCL(0);//IIC_SCL=0;
        delay_us(4);
        IIC_SCL(1);//IIC_SCL=1;
        receive<<=1;
        if(READ_SDA)receive++;
        delay_us(1);
    }
    if(!ack)
        i2c_NAck();//发送nACK
    else
        i2c_Ack(); //发送ACK
    return receive;
}