蓝桥杯-CT107单片机综合实训平台-IIC

ID:142045 · 发表于 2019-3-21 09:07

/*
  程序说明: IIC总线驱动程序
  软件环境: Keil uVision 4.10
  硬件环境: CT107单片机综合实训平台 8051，12MHz
  日期: 2011-8-9
*/

#include "reg52.h"
#include "intrins.h"

#define DELAY_TIME 5

#define SlaveAddrW 0xA0
#define SlaveAddrR 0xA1

//总线引脚定义
sbit SDA = P2^1;  /* 数据线 */
sbit SCL = P2^0;  /* 时钟线 */

void IIC_Delay(unsigned char i)
{
do{_nop_();}
while(i--);
}
//总线启动条件
void IIC_Start(void)
{
SDA = 1;
SCL = 1;
IIC_Delay(DELAY_TIME);
SDA = 0;
IIC_Delay(DELAY_TIME);
SCL = 0;
}

//总线停止条件
void IIC_Stop(void)
{
SDA = 0;
SCL = 1;
IIC_Delay(DELAY_TIME);
SDA = 1;
IIC_Delay(DELAY_TIME);
}

//发送应答
void IIC_SendAck(bit ackbit)
{
SCL = 0;
SDA = ackbit;    // 0：应答，1：非应答
IIC_Delay(DELAY_TIME);
SCL = 1;
IIC_Delay(DELAY_TIME);
SCL = 0;
SDA = 1;
IIC_Delay(DELAY_TIME);
}

//等待应答
bit IIC_WaitAck(void)
{
bit ackbit;

SCL  = 1;
IIC_Delay(DELAY_TIME);
ackbit = SDA;
SCL = 0;
IIC_Delay(DELAY_TIME);
return ackbit;
}

//通过I2C总线发送数据
void IIC_SendByte(unsigned char byt)
{
unsigned char i;

for(i=0; i<8; i++)
{
      SCL  = 0;
      IIC_Delay(DELAY_TIME);
      if(byt & 0x80) SDA  = 1;
      else SDA  = 0;
      IIC_Delay(DELAY_TIME);
      SCL = 1;
      byt <<= 1;
      IIC_Delay(DELAY_TIME);
}
SCL  = 0;
}

//从I2C总线上接收数据
unsigned char IIC_RecByte(void)
{
unsigned char i, da;
for(i=0; i<8; i++)
{
SCL = 1;
IIC_Delay(DELAY_TIME);
da <<= 1;
if(SDA) da |= 1;
SCL = 0;
IIC_Delay(DELAY_TIME);
}
return da;
}

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