Diff: QuadEnc.cpp

Revision:

0:9afc272fa65f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QuadEnc.cpp	Fri Jun 24 21:03:20 2016 +0000
@@ -0,0 +1,56 @@
+/**
+ * @file QuadEnc.cpp
+ * @date June 2nd, 2016
+ * @author Weimen Li
+ */
+
+#include "QuadEnc.hpp"
+
+QuadEnc::QuadEnc(PinName ChannelA, PinName ChannelB, float CPR) :
+count(0), bHasNewCount(false),
+CPR(CPR), ChannelAIn(ChannelA), ChannelBIn(ChannelB), ChannelAInter(ChannelA), ChannelBInter(ChannelB),
+prevCount(0), prevRevs(0), enc_val(0) {
+    
+    // Configure Channel A interrupt to trigger on rise and fall.
+    ChannelAInter.rise(this, &QuadEnc::QuadEncISR);
+    ChannelAInter.fall(this, &QuadEnc::QuadEncISR);
+
+    // Configure Channel B interrupt to trigger on rise and fall.
+    ChannelBInter.rise(this, &QuadEnc::QuadEncISR);
+    ChannelBInter.fall(this, &QuadEnc::QuadEncISR);
+
+}
+
+QuadEnc::~QuadEnc() {
+
+}
+
+void QuadEnc::QuadEncISR() {
+    uint8_t QuadEncData = (ChannelAIn.read() << 1) | ChannelBIn.read();
+    const int8_t QuadEncLUT[16] = { 0, -1, 1, 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 1,
+            -1, 0 };
+    enc_val = enc_val << 2;
+    enc_val = enc_val | QuadEncData;
+    count += QuadEncLUT[enc_val & 0b1111];
+    bHasNewCount = true;
+}
+
+bool QuadEnc::hasNewCount() {
+    bool returnVal = bHasNewCount;
+    bHasNewCount = false;
+    return returnVal;
+}
+
+float QuadEnc::getRevs() {
+    // Capture the current count to avoid corruption.
+    float currentCount = count;
+    if (prevCount != currentCount) {
+        prevRevs = currentCount / CPR;
+    }
+    return prevRevs;
+}
+
+void QuadEnc::reset() {
+    count = 0;
+    bHasNewCount = false;
+}