RfID reader C code

Kod C - [rozwiń]
#include	<pic.h>
#include	"sci.h"
void main(void)
{
// 8-bit mode at 9600 baud using polling
unsigned char data,a=0;
sci_Init(9600,SCI_EIGHT);
sci_PutByte(0x55);	/* send 0xaa when device is ready */
data = sci_GetByte();	/* read data when device is ready */
a=data;
}

#include <pic.h>
#include "sci.h"
 
/* Routines for initialisation and use of the SCI
 * for the PIC processor.
 */
 
/* other options:
 * frame errors
 */
 
unsigned char
sci_Init(unsigned long int baud, unsigned char ninebits)
{
	int X;
	unsigned long tmp;
 
	/* calculate and set baud rate register */
	/* for asynchronous mode */
	tmp = 16UL * baud;
	X = (int)(FOSC/tmp) - 1;
	if((X>255) || (X<0))
	{
		tmp = 64UL * baud;
		X = (int)(FOSC/tmp) - 1;
		if((X>255) || (X<0))
		{
			return 1;	/* panic - baud rate unobtainable */
		}
		else
			BRGH = 0;	/* low baud rate */
	}
	else
		BRGH = 1;	/* high baud rate */
	SPBRG = X;	/* set the baud rate */
 
	SYNC = 0;	/* asynchronous */
	SPEN = 1;	/* enable serial port pins */
	CREN = 1;	/* enable reception */
	SREN = 0;	/* no effect */
	TXIE = 0;	/* disable tx interrupts */
	RCIE = 0;	/* disable rx interrupts */
	TX9  = ninebits?1:0;	/* 8- or 9-bit transmission */
	RX9  = ninebits?1:0;	/* 8- or 9-bit reception */
	TXEN = 1;	/* enable the transmitter */
 
	return 0;
}
 
void
sci_PutByte(unsigned char byte)
{
	while(!TXIF)	/* set when register is empty */
		continue;
	TXREG = byte;
 
	return;
}
 
unsigned char
sci_GetByte(void)
{
	while(!RCIF)	/* set when register is not empty */
		continue;
 
	return RCREG;	/* RXD9 and FERR are gone now */
}
 
unsigned char
sci_CheckOERR(void)
{
	if(OERR)	/* re-enable after overrun error */
	{
		CREN = 0;
		CREN = 1;
		return 1;
	}
 
	return 0;
}
 
#define sci_PutNinth(bitnine)	(TX9D = bitnine?1:0
 
unsigned char
sci_GetNinth(void)
{
	while(!RCIF)
		continue;
 
	return RX9D;	/* RCIF is not cleared until RCREG is read */
}
 
unsigned char
sci_GetFERR(void)
{
	while(!RCIF)
		continue;
 
	return FERR;	/* RCIF is not cleared until RCREG is read */
}

#define FOSC	(4000000L)
#define SCI_EIGHT	(0)
#define SCI_NINE	(1)
 
unsigned char	sci_Init(unsigned long int, unsigned char);
void 		sci_PutByte(unsigned char);
unsigned char	sci_GetByte(void);
void 		sci_PutNinth(unsigned char);
unsigned char	sci_GetNinth(void);
unsigned char	sci_GetFERR(void);
unsigned char	sci_CheckOERR(void);