I2C通信

i2c.h

#ifndef __I2C_H__
#define __I2C_H__

void i2c_start();

void i2c_stop();

void i2c_send(unsigned char byte);

unsigned char i2c_receive();

void i2c_send_ack(bit status);

bit i2c_receive_ack();

#endif

i2c.c

#include "i2c.h"
#include <STC89C5xRC.H>

// 需要开漏输出模式
sbit i2c_scl = P0^0;
sbit i2c_sda = P0^1;

void i2c_start() {
	i2c_sda = 1;
	i2c_scl = 1;
	i2c_sda = 0;
	i2c_scl = 0;
}

void i2c_stop() {
	i2c_sda = 0;
	i2c_scl = 1;
	i2c_sda = 1;
}

void i2c_send(unsigned char byte) {
	unsigned char i = 0;
	for(i = 0; i < 8; ++i) {
		i2c_sda = byte & (0x80 >> i);
		i2c_scl = 1;
		i2c_scl = 0;
	}
}

unsigned char i2c_receive() {
	unsigned char byte = 0x00;
	unsigned char i = 0;
	i2c_sda = 1;
	for(i = 0; i < 8; ++i) {
		i2c_scl = 1;
		if(i2c_sda) {
			byte |= (0x80 >> i);
		}
		i2c_scl = 0;
	}
	return byte;
}

void i2c_send_ack(bit status) {
	i2c_sda = status;
	i2c_scl = 1;
	i2c_scl = 0;
}

bit i2c_receive_ack() {
	bit ack;

	i2c_sda = 1;
	i2c_scl = 1;
	ack = i2c_sda;
	i2c_scl = 0;

	return ack;
}