Reiko Randoja / QED

Quadrature decoder

Dependents:   Telliskivi2_2014

qed.cpp

Committer:
Reiko
Date:
2013-09-14
Revision:
2:72d7f93f2881
Parent:
1:83b43784d90c

File content as of revision 2:72d7f93f2881:

#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; 
}