//等待应答信号到来
//返回值：1，接收应答失败
// 0，接收应答成功
u8 MPU_IIC_Wait_Ack(void)
{
u8 ucErrTime=0;
MPU_SDA_IN(); //SDA设置为输入
MPU_IIC_SDA=1;MPU_IIC_Delay();
MPU_IIC_SCL=1;MPU_IIC_Delay();
while(MPU_READ_SDA)
{
ucErrTime++;
if(ucErrTime>250)
{
MPU_IIC_Stop();
return 1;
}
}
MPU_IIC_SCL=0;//时钟输出0
return 0;
}
u8 MPU_I2C_readByte(u8 ack)
{
u8 i, recv = 0;
MPU_SDA_IN();
for(i = 0;i < 8;i ++)
{
MPU_I2C_SCL = 0;
MPU_I2C_DELAY();
MPU_I2C_SCL = 1;
MPU_I2C_DELAY();
if(MPU_I2C_SDA_R) recv ++;
recv <<= 1;
MPU_I2C_DELAY();
}
MPU_I2C_SCL = 0;
MPU_I2C_respond(ack);
return recv;
}
//读1个字节，ack=1时，发送ACK，ack=0，发送nACK
u8 MPU_IIC_Read_Byte(unsigned char ack)
{
unsigned char i,receive=0;
MPU_SDA_IN();//SDA设置为输入
for(i=0;i<8;i++ )
{
MPU_IIC_SCL=0;
MPU_IIC_Delay();
MPU_IIC_SCL=1;
receive<<=1;
if(MPU_READ_SDA)receive++;
MPU_IIC_Delay();
}
if (!ack)
MPU_IIC_NAck();//发送nACK
else
MPU_IIC_Ack(); //发送ACK
return receive;
}
u8 MPU_I2C_waitACK()
{
u8 errTime = 0;
//MPU_SDA_OUT();
//MPU_I2C_SCL = 0;
//MPU_I2C_DELAY();
//MPU_I2C_SDA_W = 1;
//MPU_I2C_DELAY();
MPU_I2C_SCL = 1;
MPU_I2C_DELAY();
MPU_SDA_IN();
while(MPU_I2C_SDA_R)
{
errTime ++;
if(errTime > 250)
{
MPU_I2C_stop();
return 1;
}
}
MPU_I2C_SCL = 0;//拉低SCL,等待发送或接收数据
MPU_I2C_DELAY();
return 0;
}
