com.c

mb90540 fujitsu

/* THIS SAMPLE CODE IS PROVIDED AS IS AND IS SUBJECT TO ALTERATIONS. FUJITSU */
/* MICROELECTRONICS ACCEPTS NO RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR */
/* ELIGIBILITY FOR ANY PURPOSES.                                             */
/*                 (C) Fujitsu Microelectronics Europe GmbH                  */
/************************************************************************/
/* FFMC-16LX Softune V01												*/
/* Fujitsu Mikroelektronik/Germany										*/	
/*																		*/
/* Project UART540 Member list:											*/
/*				- start.asm												*/
/*				- mb90540.asm											*/
/*				- main.c												*/
/*				- com.c													*/
/*																		*/
/* Even the program has been carefully checked and is believed to work 	*/
/* properly no warranty is given by Fujitsu.							*/
/*																		*/
/* History																*/
/*																		*/
/* Date		Rev. 	Author		Description								*/
/*14.01.00	1.00	MEN			communication functions					*/
/************************************************************************/

/******************************* Includes ***************************************/
#include "mb90540.h"

/******************************* Gloabals ***************************************/
extern unsigned char tbuf,rbuf,temp;
extern unsigned char *p_string;
extern char length;

/******************************* Strings ****************************************/
unsigned char message[] = " No answer from slave 1, check connection ";
unsigned char message2[] = " No answer from slave 2, check connection ";

/******************************* Prototyps **************************************/
void send(unsigned char);
char wait(unsigned char);
void receive_adr(void);
void receive_data(void);
void echo_ch(void);

/*============================== PROCEDURES ====================================*/
void send(unsigned char data)
{
	switch(data){
		case '1':	tbuf = '1';		/* sending address to slave1 */
					break;
		case '2':	tbuf = '2';		/* sending address to slave2 */
					break;
		case 'd':	URD0_D8 = 0;	/* set data bit */
					tbuf = 'd';		/* send data */
					break;	
		default :	tbuf = 0;		/* send nothing */
		}
}

void receive_adr(void)
{
	switch(rbuf)					/* select the address of the slave */
	{
		case '1':	URD0_D8 = 0;
					tbuf = 'a';		/* detect slave1 */
					break;
		case '2':	URD0_D8 = 0;
					tbuf = 'b';		/* detect slave2 */
					break;
		default :	tbuf = 0;
	}
}

void receive_data(void)
{
	if(rbuf == 'd')
	{
		tbuf = 'r';			/* send acknowlegde to the master */
	}
}

char wait(unsigned char value)				/* wait for response */ 
{
	unsigned int i;
	char status = 0;
	
	for(i = 0;i < 65000; i++)	/* wait loop */
	{
		if(rbuf == 'a' || rbuf == 'r' || rbuf == 'b')	/* when receiving the correct sign */
		{
			i = 0;
			tbuf = rbuf;				/* echo received character */
			rbuf = 0;					/* clear receive buffer */
			while(tbuf != 0);			/* waiting until buffer is empty */
			break;						/* leave the timeout generator */
		}
	}
	if(i >= 64000)						/* time is over */
	{
		if(value == '1')
		{
			p_string = message;				/* send error message */
			length = strlen(p_string);		/* get string lenght */
		}
		else
		{
			p_string = message2;			/* send error message */
			length = strlen(p_string);		/* get string lenght */
		}
		status = -1;
	}
	return(status); 					/* return status */
}

void echo_ch(void)
{
	tbuf = rbuf;			/* master echos received data */
	while(tbuf != 0);		/* wait until buffer is empty */
}
/*============================== END OF PROCEDURES ======================================*/