Juergen Gnoss / Mbed 2 deprecated PolledQEI

A polled Quadrature encoder Class

Dependencies:   mbed

PolledQEI.cpp@0:7c16b1d2f01e, 2011-08-30 (annotated)

Committer:
jgnoss
Date:
Tue Aug 30 19:52:34 2011 +0000
Revision:
0:7c16b1d2f01e
Child:
1:72e6e124a7e6
Working example

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jgnoss 0:7c16b1d2f01e 1 #include "mbed.h"
jgnoss 0:7c16b1d2f01e 2 #include "PolledQEI.h"
jgnoss 0:7c16b1d2f01e 3
jgnoss 0:7c16b1d2f01e 4
jgnoss 0:7c16b1d2f01e 5
jgnoss 0:7c16b1d2f01e 6
jgnoss 0:7c16b1d2f01e 7 void PolledQEI::setSampleFrequency(int i = 10000) {
jgnoss 0:7c16b1d2f01e 8 _sample_uSec = i;
jgnoss 0:7c16b1d2f01e 9 _actEncPos = 0;
jgnoss 0:7c16b1d2f01e 10 _ticker->attach_us( this, &PolledQEI::check, _sample_uSec );
jgnoss 0:7c16b1d2f01e 11 }
jgnoss 0:7c16b1d2f01e 12
jgnoss 0:7c16b1d2f01e 13 int PolledQEI::pos(void) {
jgnoss 0:7c16b1d2f01e 14 return _actEncPos;
jgnoss 0:7c16b1d2f01e 15 }
jgnoss 0:7c16b1d2f01e 16
jgnoss 0:7c16b1d2f01e 17 int PolledQEI::dir(void) {
jgnoss 0:7c16b1d2f01e 18 return _dir;
jgnoss 0:7c16b1d2f01e 19 }
jgnoss 0:7c16b1d2f01e 20
jgnoss 0:7c16b1d2f01e 21 int PolledQEI::rev(void) {
jgnoss 0:7c16b1d2f01e 22 return _actEncRev;
jgnoss 0:7c16b1d2f01e 23 }
jgnoss 0:7c16b1d2f01e 24
jgnoss 0:7c16b1d2f01e 25 void PolledQEI::countRev(void) {
jgnoss 0:7c16b1d2f01e 26 if (_dir) {
jgnoss 0:7c16b1d2f01e 27 _actEncRev++;
jgnoss 0:7c16b1d2f01e 28 } else {
jgnoss 0:7c16b1d2f01e 29 _actEncRev--;
jgnoss 0:7c16b1d2f01e 30 }
jgnoss 0:7c16b1d2f01e 31 }
jgnoss 0:7c16b1d2f01e 32
jgnoss 0:7c16b1d2f01e 33 void PolledQEI::init(PinName a, PinName b, PinName z = NC) {
jgnoss 0:7c16b1d2f01e 34
jgnoss 0:7c16b1d2f01e 35 _phaseA = new DigitalIn( a );
jgnoss 0:7c16b1d2f01e 36 _phaseA->mode( PullUp );
jgnoss 0:7c16b1d2f01e 37 _phaseB = new DigitalIn( b );
jgnoss 0:7c16b1d2f01e 38 _phaseB->mode( PullUp );
jgnoss 0:7c16b1d2f01e 39 if (z != NC) {
jgnoss 0:7c16b1d2f01e 40 _phaseZ = new InterruptIn( z );
jgnoss 0:7c16b1d2f01e 41 _phaseZ->mode( PullUp );
jgnoss 0:7c16b1d2f01e 42 _phaseZ->fall(this, &PolledQEI::countRev);
jgnoss 0:7c16b1d2f01e 43 }
jgnoss 0:7c16b1d2f01e 44 _actEncRev = 0;
jgnoss 0:7c16b1d2f01e 45 _actEncPos = 0;
jgnoss 0:7c16b1d2f01e 46 _dir = 0;
jgnoss 0:7c16b1d2f01e 47
jgnoss 0:7c16b1d2f01e 48 _ticker = new Ticker;
jgnoss 0:7c16b1d2f01e 49 }
jgnoss 0:7c16b1d2f01e 50
jgnoss 0:7c16b1d2f01e 51 void PolledQEI::check (void) {
jgnoss 0:7c16b1d2f01e 52 unsigned int pA = _phaseA->read();
jgnoss 0:7c16b1d2f01e 53 unsigned int pB = _phaseB->read();
jgnoss 0:7c16b1d2f01e 54 unsigned int newV = 0, diffV = 0;
jgnoss 0:7c16b1d2f01e 55
jgnoss 0:7c16b1d2f01e 56
jgnoss 0:7c16b1d2f01e 57 // convert gray to binary
jgnoss 0:7c16b1d2f01e 58 if ( pA ) {
jgnoss 0:7c16b1d2f01e 59 newV = 3;
jgnoss 0:7c16b1d2f01e 60 }
jgnoss 0:7c16b1d2f01e 61 if ( pB ) {
jgnoss 0:7c16b1d2f01e 62 newV ^= 1;
jgnoss 0:7c16b1d2f01e 63 }
jgnoss 0:7c16b1d2f01e 64
jgnoss 0:7c16b1d2f01e 65 diffV = last - newV; // difference last - new
jgnoss 0:7c16b1d2f01e 66 if ( diffV & 1 ) { // bit 0 = value (1)
jgnoss 0:7c16b1d2f01e 67 last = newV; // store new as next last
jgnoss 0:7c16b1d2f01e 68 _actEncPos -= (diffV & 2) - 1; // bit 1 = direction (+/-)
jgnoss 0:7c16b1d2f01e 69 _dir = (diffV & 2)?CW:CCW;
jgnoss 0:7c16b1d2f01e 70 }
jgnoss 0:7c16b1d2f01e 71 }
jgnoss 0:7c16b1d2f01e 72
jgnoss 0:7c16b1d2f01e 73