蓝桥杯之单片机学习（十九）——IIC协议（PCF8591、AT24C02）的代码文件

/* 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 somenop {_nop_();_nop_();_nop_();_nop_();_nop_();} #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 */ //总线启动条件 void IIC_Start(void) { SDA = 1; SCL = 1; somenop; SDA = 0; somenop; SCL = 0; } //总线停止条件 void IIC_Stop(void) { SDA = 0; SCL = 1; somenop; SDA = 1; } //应答位控制 void IIC_Ack(bit ackbit) { if(ackbit) { SDA = 0; } else { SDA = 1; } somenop; SCL = 1; somenop; SCL = 0; SDA = 1; somenop; } //等待应答 bit IIC_WaitAck(void) { SDA = 1; somenop; SCL = 1; somenop; if(SDA) { SCL = 0; IIC_Stop(); return 0; } else { SCL = 0; return 1; } } //通过I2C总线发送数据 void IIC_SendByte(unsigned char byt) { unsigned char i; for(i=0;i<8;i++) { if(byt&0x80) { SDA = 1; } else { SDA = 0; } somenop; SCL = 1; byt <<= 1; somenop; SCL = 0; } } //从I2C总线上接收数据 unsigned char IIC_RecByte(void) { unsigned char da; unsigned char i; for(i=0;i<8;i++) { SCL = 1; somenop; da <<= 1; if(SDA) da |= 0x01; SCL = 0; somenop; } return da; }