rfid_reader.c

#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

#define SPORT_NAME "/dev/ttyAMA0"
#define RFID_DATA_LENGTH 14
#define RFID_TAGCODE_LENGTH 10

//masterStart is inclusive, masterEnd is exclusive
void arrayCopy(char* master, char* slave, int masterStart, int masterEnd){
	int i;
	for (i = masterStart; i < masterEnd; i++)
	{
		slave[i] = master[i];
	}
}

int set_interface_attributes(int filedescriptor, int speed){
	struct termios tty;
	memset(&tty, 0, sizeof(tty));
	if (tcgetattr(filedescriptor, &tty) !=0){
		printf("Error %d from tcgetattr\n", errno);
		return -1;
	}

	cfsetospeed(&tty, speed);
	cfsetispeed(&tty, speed); //set the speed of the interface

	tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; //8 bit characters

	tty.c_iflag &= ~IGNBRK;
	tty.c_lflag = 0; //no signaling characters, no echo

	tty.c_oflag = 0; //no remapping, no delays
	tty.c_cc[VMIN] = 1; //should block								THIS SHOULD BE TURNED OFF FOR DEBUG. a debug needs to be run to see how many chars come from the RFID tag
	tty.c_cc[VTIME] = 10; //1 second timeout

	tty.c_iflag &= ~(IXON | IXOFF | IXANY); //shut off xon/xoff control

	tty.c_cflag |= (CLOCAL | CREAD); //ignore modem controls //enable reading

	tty.c_cflag &= ~(PARENB | PARODD); //no parity

	tty.c_cflag &= ~CSTOPB;
	tty.c_cflag &= ~CRTSCTS; //no hardware flow control

	if (tcsetattr(filedescriptor, TCSANOW, &tty) != 0) {
		printf("error %d from tcsetattr\n", errno);
		return -1;
	}

	return 0;

}

int main(int argc, char const *argv[])
{

	char *serialPortName = SPORT_NAME;

	int sport_fd = open (serialPortName, O_RDWR | O_NOCTTY | O_SYNC);
	if (sport_fd < 0){
		printf("error %d from file open\n", errno);
	}
	set_interface_attributes(sport_fd, B9600); //setup the attributes

	char *fifoName = "/var/run/RFID_FIFO"; //this needs to be the same in the java program

	mkfifo(fifoName, 0666);
	int fifo_fd;
		printf("trying to open fifo\n");
		fifo_fd = open(fifoName, O_WRONLY);
		if (fifo_fd !=0){
			printf("possible error opening FIFO - open returned %d\n", fifo_fd);
		}
		printf("Serial port setup, waiting on tag read\n");

	//Do stuff with the fifo:
	//write(fifo_fd, "test", sizeof("test"));
	int j;
	while (1)
	{
		char buf[RFID_DATA_LENGTH];
		char tagCode[RFID_TAGCODE_LENGTH];
		memset(buf, 0xFF, sizeof(buf));
		int n = read(sport_fd,buf,sizeof(buf));

		arrayCopy(buf, tagCode, 1, 12);

		int i;
		// for (i = 0; i < RFID_TAGCODE_LENGTH; ++i){
		// 	printf("%x", tagCode[i]);
		// } FROM TESTING
		// printf("\n");

		write(fifo_fd, tagCode, sizeof(tagCode));
		n = read(sport_fd, buf, sizeof(buf));
	}

	close(fifo_fd);
	unlink(fifoName);
	return 0;
}