Reading RFID tags
From Mech
Original Assignment
Interface your PIC with an RFID reader (see here) and demonstrate recognition of various RFID tags.
Overview
Radio Frequency Identification (RFID) reads passive RFID transponder tags up to 4 inches away from the reader. The RFID communicates using rs232 and transmits a 12-byte ASCII string. The first byte (start byte) is always $0A and the last byte (stop byte) is always $0D. The 10 middle digits are the 10 unique id digits that are unique to every RFID transponder.
Circuit
Code
/* RFID_Input.c J.Cooper and C.Ryan 2009-2-04 Read in from RFID Card on pin RC7 Write out RFID unique number on pin RC6 */
#include <18f4520.h> #fuses HS,NOLVP,NOWDT,NOPROTECT #use delay(clock=40000000) // 40 MHz crystal on PCB #use rs232(baud=2400, UART1) // hardware UART; uses RC6/TX and RC7/RX int16 i; char value[12];//12 values of tag ID output_low(PIN_D7); //Set enable to low void main() { for (i=0; i<12; i++) { //read in the 12 values value[i]=getc(); } printf("rfid# %c %c %c %c %c %c %c %c %c %c \r\n", value[1] value[2] value[3] value[4] value[5] value[6] value[7] value[8] value[9] value[10]); //display 10 unique id digits }