i2c_start.c

这是适用I/O口模拟的 I2C 程序

/***************************** File  Message *******************************
** File Name : I2C.c
** created by: ZhangBinn
** Last modified: 12/28/04 (MM/DD/YY)
** Description:  this file is specified for I2C devices,such as 24LC32
***************************************************************************/
#include   <pic.h>
#include   "delay.h"
#include   "define.h"

/* I2C module uses PORT C */
#define		I2C_CTRL        TRISC
#define		I2C_LINE        PORTC

#define		SCL             RC3                 /* clock on port C bit 3 */
#define 	SCL_DIR         TRISC3
#define 	SCL_DIR_IN()    (SCL = 1)
#define 	SCL_DIR_OUT()   (SCL = 0)

#define 	SDA     	    RC4             /* data on port C bit 4 */
#define 	SDA_DIR         TRISC4
#define 	SDA_DIR_IN()    (SDA = 1)
#define 	SDA_DIR_OUT()   (SDA = 0)

#define 	__I2C_DELAY      20
#define     I2C_DELAY()      DelayNus(__I2C_DELAY)

#define     RD_ID           	0xA1
#define     WR_ID           	0xA0



/*************************** Function  Message ****************************
** Funtion Name : I2C_Start
** Arguments: BYTE bComOrder: the communication order
** Return Value:   return  the communication status
** Restrictions:   none
** created by: ZhangBin
** Last modified: 12/2/04 (MM/DD/YY)
** Description:  the main program  of the EOS System
***************************************************************************/
void    I2C_Start(void)
{
 	SDA_DIR = 0; 
 	SCL_DIR = 0;

 	SDA_DIR_IN();              //SDA = 1;
 	I2C_DELAY();
 
 	SCL_DIR_IN();             // SCL = 1;
 	I2C_DELAY();
 
 	SDA_DIR_OUT();            // SDA = 0;
 	I2C_DELAY();       
 
 	SCL_DIR_OUT();            // SCL = 0;
};

/*************************** Function  Message ****************************
** Funtion Name : I2C_ReStart
** Arguments: BYTE bComOrder: the communication order
** Return Value:   return  the communication status
** Restrictions:   none
** created by: ZhangBin
** Last modified: 12/2/04 (MM/DD/YY)
** Description:  the main program  of the EOS System
***************************************************************************/
void    I2C_ReStart(void)
{
 	SCL_DIR_OUT();            // SCL = 0;
 	SDA_DIR_IN();             // SDA = 1;
 	I2C_DELAY();
 
 	SCL_DIR_IN();             // SCL = 1;
 	I2C_DELAY();

 	SDA_DIR_OUT();            // SDA = 0;
 	I2C_DELAY();       
 
 	SCL_DIR_OUT();            // SCL = 0;
};