ID12RFID.cpp

00001 /* mbed ID12 RFID Library
00002  * Copyright (c) 2007-2011, sford, http://mbed.org
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 // modified to use interrupts
00024 
00025 #include "ID12RFID.h"
00026 
00027 #include "mbed.h"
00028 
00029 ID12RFID::ID12RFID(PinName rx)
00030         : _rfid(NC, rx) {
00031         nbuffer = 0;
00032         last = 0;
00033         _rfid.attach(this, &ID12RFID::handler);
00034 }
00035 
00036 void ID12RFID::handler() {
00037     buffer[nbuffer] = _rfid.getc();
00038     if(buffer == 0) {               // waiting for '2'
00039         if(buffer[nbuffer] != 2) {  // is not '2'
00040             return;                 // so ignore
00041         }
00042     }
00043     nbuffer++;
00044     
00045     // 2 x x 8 chars x x x x 
00046     if(nbuffer > 15) {
00047         last = 0;
00048         for(int i=7; i>=0; i--) {
00049             char c = buffer[10 - i]; // a ascii hex char
00050             int part = c - '0';
00051             last |= part << (i * 4);
00052         }
00053         nbuffer = 0;
00054     }
00055 }
00056 
00057 int ID12RFID::readable() {
00058     return (last > 0); //_rfid.readable();
00059 }
00060 
00061 int ID12RFID::read() {
00062    int t = last;
00063    last = 0;
00064    return t;
00065 }