i2c.c

来自「AVR,系列单片机MEGA48应用例程,包括原理图,代码基本包括全部资源的配置应」· C语言 代码 · 共 86 行

#include"I2C.H"
#ifdef  IAR_DEMO
#include <iom48.h>
#include <ioavr.h>
#include <inavr.h>
#else 
#include <iom48v.h>
#include <macros.h>
#endif


unsigned char i2c_Write(unsigned char Addr,unsigned char Write_Byte) 
{     
    //  PORTC|=0x30;
	
	  Start();//I2C启动
	  Wait();
	  if(TestAck()!=START) 
	  goto end_i2c_write;
	  
	  Write8Bit(wr_device_add);//写I2C从器件地址和写方式
	  Wait();
	  if(TestAck()!=MT_ADDR_ACK)
	  goto end_i2c_write;
	    	
	  Write8Bit(Addr);	 		//写24C02的ROM地址
	  Wait();
	  if(TestAck()!=MT_DATA_ACK)
	  goto end_i2c_write;

	  Write8Bit(Write_Byte);//写数据到24C02的ROM
	  Wait();
	  if(TestAck()!=MT_DATA_ACK) 	
	  goto end_i2c_write;
	  Stop();//I2C停止
	  return 1;
end_i2c_write:
	  Stop();//I2C停止
      return 0;
	
}

/******************************************
      I2C总线读一个字节(Mega8 as Master)
		   如果读失败也返回0
*/
unsigned char i2c_Read(unsigned char Addr, unsigned char * Read_Byte)       //this is a sample of reading 24c01(EEPROM)
      {
	   
	  // PORTC|=0x30;
	
	   Start();//I2C启动
	   Wait();
	   if (TestAck()!=START) 
	   goto end_i2c_read;//ACK	   
	   Write8Bit(wr_device_add);//写I2C从器件地址和写方式
	   Wait(); 
	   if (TestAck()!=MT_ADDR_ACK) 
	   goto end_i2c_read;//ACK
	  
	   Write8Bit(Addr);//写24C02的ROM地址
	   Wait();
	   if (TestAck()!=MT_DATA_ACK) 
	   goto end_i2c_read;;

	   Start();//I2C重新启动
	   Wait();
	   if (TestAck()!=RE_START)  
	   goto end_i2c_read;
	   Write8Bit(rd_device_add);//写I2C从器件地址和读方式
	   Wait();
	   if(TestAck()!=MR_ADDR_ACK) 
	   goto end_i2c_read;
	   Twi();//启动主I2C读方式
	   Wait();
	   if(TestAck()!=MR_DATA_NOACK) 
	   goto end_i2c_read;
	   *Read_Byte=TWDR;//读取I2C接收数据
	   Stop();//I2C停止
       return 1;
	   end_i2c_read:
	   Stop();//I2C停止
       return 0; 
      }