Juergen Gnoss / Mbed 2 deprecated PolledQEI

A polled Quadrature encoder Class

Dependencies:   mbed

PolledQEI.cpp@1:72e6e124a7e6, 2011-08-30 (annotated)

Committer:
jgnoss
Date:
Tue Aug 30 20:03:36 2011 +0000
Revision:
1:72e6e124a7e6
Parent:
0:7c16b1d2f01e 
Added Phase Z and Rev Counter

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jgnoss 1:72e6e124a7e6 1 #include "mbed.h"
jgnoss 1:72e6e124a7e6 2 #include "PolledQEI.h"
jgnoss 1:72e6e124a7e6 3
jgnoss 1:72e6e124a7e6 4
jgnoss 1:72e6e124a7e6 5
jgnoss 1:72e6e124a7e6 6
jgnoss 1:72e6e124a7e6 7 void PolledQEI::setSampleFrequency(int i = 10000) {
jgnoss 1:72e6e124a7e6 8 _sample_uSec = i;
jgnoss 1:72e6e124a7e6 9 _actEncPos = 0;
jgnoss 1:72e6e124a7e6 10 _ticker->attach_us( this, &PolledQEI::check, _sample_uSec );
jgnoss 1:72e6e124a7e6 11 }
jgnoss 1:72e6e124a7e6 12
jgnoss 1:72e6e124a7e6 13 int PolledQEI::pos(void) {
jgnoss 1:72e6e124a7e6 14 return _actEncPos;
jgnoss 1:72e6e124a7e6 15 }
jgnoss 1:72e6e124a7e6 16
jgnoss 1:72e6e124a7e6 17 int PolledQEI::dir(void) {
jgnoss 1:72e6e124a7e6 18 return _dir;
jgnoss 1:72e6e124a7e6 19 }
jgnoss 1:72e6e124a7e6 20
jgnoss 1:72e6e124a7e6 21 int PolledQEI::rev(void) {
jgnoss 1:72e6e124a7e6 22 return _actEncRev;
jgnoss 1:72e6e124a7e6 23 }
jgnoss 1:72e6e124a7e6 24
jgnoss 1:72e6e124a7e6 25 void PolledQEI::countRev(void) {
jgnoss 1:72e6e124a7e6 26 if (_dir) {
jgnoss 1:72e6e124a7e6 27 _actEncRev++;
jgnoss 1:72e6e124a7e6 28 } else {
jgnoss 1:72e6e124a7e6 29 _actEncRev--;
jgnoss 1:72e6e124a7e6 30 }
jgnoss 1:72e6e124a7e6 31 }
jgnoss 1:72e6e124a7e6 32
jgnoss 1:72e6e124a7e6 33 void PolledQEI::init(PinName a, PinName b, PinName z = NC) {
jgnoss 1:72e6e124a7e6 34
jgnoss 1:72e6e124a7e6 35 _phaseA = new DigitalIn( a );
jgnoss 1:72e6e124a7e6 36 _phaseA->mode( PullUp );
jgnoss 1:72e6e124a7e6 37 _phaseB = new DigitalIn( b );
jgnoss 1:72e6e124a7e6 38 _phaseB->mode( PullUp );
jgnoss 1:72e6e124a7e6 39 if (z != NC) {
jgnoss 1:72e6e124a7e6 40 _phaseZ = new InterruptIn( z );
jgnoss 1:72e6e124a7e6 41 _phaseZ->mode( PullUp );
jgnoss 1:72e6e124a7e6 42 _phaseZ->fall(this, &PolledQEI::countRev);
jgnoss 1:72e6e124a7e6 43 }
jgnoss 1:72e6e124a7e6 44 _actEncRev = 0;
jgnoss 1:72e6e124a7e6 45 _actEncPos = 0;
jgnoss 1:72e6e124a7e6 46 _dir = 0;
jgnoss 1:72e6e124a7e6 47
jgnoss 1:72e6e124a7e6 48 _ticker = new Ticker;
jgnoss 1:72e6e124a7e6 49 }
jgnoss 1:72e6e124a7e6 50
jgnoss 1:72e6e124a7e6 51 void PolledQEI::check (void) {
jgnoss 1:72e6e124a7e6 52 unsigned int pA = _phaseA->read();
jgnoss 1:72e6e124a7e6 53 unsigned int pB = _phaseB->read();
jgnoss 1:72e6e124a7e6 54 unsigned int newV = 0, diffV = 0;
jgnoss 1:72e6e124a7e6 55
jgnoss 1:72e6e124a7e6 56
jgnoss 1:72e6e124a7e6 57 // convert gray to binary
jgnoss 1:72e6e124a7e6 58 if ( pA ) {
jgnoss 1:72e6e124a7e6 59 newV = 3;
jgnoss 1:72e6e124a7e6 60 }
jgnoss 1:72e6e124a7e6 61 if ( pB ) {
jgnoss 1:72e6e124a7e6 62 newV ^= 1;
jgnoss 1:72e6e124a7e6 63 }
jgnoss 1:72e6e124a7e6 64
jgnoss 1:72e6e124a7e6 65 diffV = last - newV; // difference last - new
jgnoss 1:72e6e124a7e6 66 if ( diffV & 1 ) { // bit 0 = value (1)
jgnoss 1:72e6e124a7e6 67 last = newV; // store new as next last
jgnoss 1:72e6e124a7e6 68 _actEncPos -= (diffV & 2) - 1; // bit 1 = direction (+/-)
jgnoss 1:72e6e124a7e6 69 _dir = (diffV & 2)?CW:CCW;
jgnoss 1:72e6e124a7e6 70 }
jgnoss 1:72e6e124a7e6 71 }
jgnoss 1:72e6e124a7e6 72
jgnoss 1:72e6e124a7e6 73