i2c_demo.c

renasas m16c上实现iic通信的源代码.

/**************************************************************************/
/**MITSUBISHI**MITSUBISHI**MITSUBISHI**MITSUBISHI**MITSUBISHI**MITSUBISHI**/
/**************************************************************************/
/**************************************************************************/
/*  DISCLAIMER:                                                           */
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/*  PARTICULAR PURPOSE.                                                   */
/**************************************************************************/
/**************************************************************************/
/*                                                                        */
/*     Module  :   I2C_DEMO.C                                             */
/*     Purpose :   Demo I2C Bus Program                                   */
/*                                                                        */
/*     Author  :   Tim Wendland                                           */
/*     			   Mitsubishi Electric Europe B.V.                        */
/*                 EDEC                                                   */
/*     Date    :   July 2000                                              */
/*                                                                        */
/*     This program demonstrates the use the UART2 in the clock-          */
/*     synchronous mode to implement a I2C bus, which communicates        */
/*     with a Microchip 24C01 EEPROM                                      */
/*                                                                        */
/**************************************************************************/

#include    <stdio.h>
#include    <ctype.h>
#include    <stdlib.h>
#include    "sfr62.h"
#include    "alias.h"
#include 	"i2c_demo.h"
#include    "i2c.h"

/**************************************************************************
* Prototypes of Functions
**************************************************************************/

void init_sys(void);
void init_i2c_bus(void);
void read_eeprom_cmd(void);
void write_eeprom_cmd(void);

/**************************************************************************
* Global Variables
**************************************************************************/

unsigned char i2c_ram[256];	// RAM region used in I2C slave transmission and reception.
extern unsigned char status;	

/***************************************************************************/

void far main(void)
{
    init_sys();      /* Initalize System Clock   */
    init_i2c_bus();  /* Initalize i2c Bus        */
	asm("fset i");

	while (1)
	{
	    asm("nop");
	    
	    write_eeprom_cmd();

        asm("nop");

		read_eeprom_cmd();

        asm("nop");

	}					
}

/***************************************************************************/

void read_eeprom_cmd(void)
{

	while(check_i2c_bus_status(Set_flag))
	{   
		// Check if i2c bus is not busy and set the bus flag.
	} 
	
	i2c_ram[0] = 0x00;	// Start address
 	
 	if(iic_mw_start(0x01,&i2c_ram[0],0x50) != 0)// iic_mw_start(0x01,&i2c_ram[0],0x50);
												// 1st Argument: Designate data length sent by master
												// 2nd Argument: Designate leading address of where data are stored
												// 3rd Argument: Designate the address of the slave device

 	{
		// For DEMO we do not provide any error checking. 
		if(Get_error_mass() != 0)
			asm("nop");
	}

	while(check_i2c_bus_status(0))
	{    
		// wait for read to be completed.   
	}
	
	// For DEMO we do not provide any error checking. 
	if(Get_error_mass() != 0)
			asm("nop");
	else
	{
        /* read  data */
		
		while(check_i2c_bus_status(Set_flag))
		{	 
			// Check if i2c bus is not busy and set the busy flag 
		}
		if(iic_mr_start(0x02,&i2c_ram[0],0x50)!= 0)
		{
			// For DEMO we do not provide any error checking. 
			if(Get_error_mass() != 0)
				asm("nop");
		}
		while(check_i2c_bus_status(0))
		{	 
			// wait for read to be completed.   
		}
		
		// For DEMO we do not provide any error checking. 
		if(Get_error_mass() != 0)		// Post process error checking 
			asm("nop");
		else
		{	
			asm("nop");
		}
	}
 
}

/***************************************************************************/

void write_eeprom_cmd(void)
{
	i2c_ram[0] = 0x00;
	i2c_ram[1] = 0x56;
	i2c_ram[2] = 0x78;
 
    while(check_i2c_bus_status(Set_flag))
    {    
   	    // repeat until bus is finished 
   	}

	iic_mw_start(0x03,&i2c_ram[0],0x50);		// 1st Argument: Designate data length sent by master
												// 2nd Argument: Designate leading address of where data are stored
												// 3rd Argument: Designate the address of the slave device
	
	while(check_i2c_bus_status(0))
	{    
		// wait for read to be completed.   
	}
}

/***************************************************************************/

void init_sys(void)
{
/* System clock initialization */
    prc0 = 0x01;        // Write enable sys clock
    cm0  = 0x00;        // Set system clock
    cm1  = 0x00;        // divide main clock by 16
    prc0 = 0x00;        // disable protect reg
}

/***************************************************************************/

void init_i2c_bus(void)		 // Initizes I2C slave functions 
{
unsigned char *MEM;
int i;
 MEM = &i2c_ram[0];
 if( iic_stop() == 0){		 /* Check fpr current use. kill bus intialize for start of new message */
 	init_i2c_mas_func();
 	iic_ini(0x54, i2c_ram);	 // Intialize I2C device driver. 
	for (i=0;i<128;i++){
		*MEM++ = 0xff;		 /* zero out ram buffer. */ 
		}
	}
  }
/***************************************************************************/