Diff: QED/qed.cpp

Revision:

0:ef6268629f0b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QED/qed.cpp	Fri Sep 28 10:46:57 2018 +0000
@@ -0,0 +1,33 @@
+#include "qed.h"
+
+QED::QED(PinName channelA, PinName channelB)
+    : interruptA(channelA), interruptB(channelB) {
+ 
+    pulses = 0;
+    currState = (interruptA.read() << 1) | (interruptB.read());
+    prevState = currState;
+ 
+    interruptA.rise(this, &QED::decode);
+    interruptA.fall(this, &QED::decode);
+    interruptB.rise(this, &QED::decode);
+    interruptB.fall(this, &QED::decode); 
+}
+
+int QED::read() {
+    int pulseCount = pulses;
+    pulses = 0;
+    return pulseCount;
+}
+
+void QED::decode() {
+    currState = (interruptA.read() << 1) | (interruptB.read()); 
+   
+    int change = (prevState & PREV_MASK) ^ ((currState & CURR_MASK) >> 1);
+
+    if (change == 0) {
+        change = -1;
+    }
+
+    pulses -= change;  
+    prevState = currState; 
+}
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