Diff: wiegand.h

Revision:

0:033aa4854957

Child:

1:024f831fa51e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wiegand.h	Thu Feb 03 18:48:04 2011 +0000
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2011 Paul van der Wielen, Pro-Serv
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to use
+ * and implement the software for none commercial reason and usage only and
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * Usage and assumptions:
+ * a RFID reader Model MF7(1.05) is configured in wiegand mode and attached 
+ * ports per call to class (could be to p5 & p6 via a level converter as to
+ * isolate the 5V source voltage from the 3.3V needed by MCU, this can easily
+ * be done with diode in series with signal data0 and data1 of RFID reader and
+ * pull up on MCU side.
+ *
+ * Note:    using 'Wiegand' format rfid reader has one drawback as it only is capable
+ *          of returning 6 digits out of the 8 digits of the full RFID code, which is
+ *          the case for an 1K MiFare card.
+ *          Benefit is that a lot of Wiegand compatible reader do exist from various
+ *          brands at an reasonable price.
+ */
+ 
+#include "mbed.h"
+
+class Wiegand {
+public:
+    Wiegand(PinName pin0, PinName pin1) : _D0(pin0), _D1(pin1) { // create the InterruptIn on the pin specified to Wiegand
+        _D0.mode(PullUp);
+        _D1.mode(PullUp);
+        _D0.rise(this, &Wiegand::data_0); // attach data_0 function of this wiegand instance
+        _D1.rise(this, &Wiegand::data_1); // attach data_1 function of this wiegand instance         
+    }
+
+    /*
+     * Interrupt driven signal from data0 data line
+     */
+    void data_0() {
+        if (_pulses == 26) {
+            clear();
+        }
+        _wiegand = ((_wiegand << 1) & 0x3ffffff) + 0x00;
+        if (_pulses < 13) {
+            _e_par = (_e_par & 0x01);
+        } else {
+            _e_par = (_e_par & 0x01);
+        }
+        _pulses++;
+    }
+    
+    /*
+     * Interrupt driven signal from data1 data line
+     */
+    void data_1() {
+        if (_pulses == 26) {
+            clear();
+        }
+        _wiegand = ((_wiegand << 1) & 0x3ffffff) + 0x01;
+        if (_pulses < 13) {
+            _o_par = (_o_par & 0x01) + 0x01;
+        } else {
+            _o_par = (_o_par & 0x01) + 0x01;
+        }
+        _pulses++;
+    }
+    
+    /*
+     * Various callable class members as to obtain data parts
+     */
+    unsigned long site() {
+        return (_wiegand >> 17) & 0xff;
+    }
+    
+    unsigned long data() {
+        return (_wiegand >> 1) & 0xffff;
+    }
+    
+    unsigned long rfid() {
+        return (_wiegand >> 1) & 0xffffff;
+    }
+    
+    /*
+     * returns true if we have read all pulses and we have proper parity for both data halves
+     */
+    bool readable() {
+        if (( _pulses == 26) && (_e_par == 0) && (_o_par == 1)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+    
+    /*
+     * clear last read card entry, prepare for next card entry
+     */
+    void clear() {
+        _pulses = _e_par = _o_par = 0;
+        _wiegand = 0;
+    }
+    
+private:
+    InterruptIn _D0;
+    InterruptIn _D1;
+    volatile unsigned long _wiegand;
+    volatile unsigned int _pulses;
+    volatile unsigned int _e_par;
+    volatile unsigned int _o_par;
+};
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