Michael Shimniok / Mbed 2 deprecated AVC_2012

Code for autonomous ground vehicle, Data Bus, 3rd place winner in 2012 Sparkfun AVC.

Dependencies:   Watchdog mbed Schedule SimpleFilter LSM303DLM PinDetect DebounceIn Servo

Sensors/IncrementalEncoder/IncrementalEncoder.cpp@0:826c6171fc1b, 2012-06-20 (annotated)

Committer:
shimniok
Date:
Wed Jun 20 14:57:48 2012 +0000
Revision:
0:826c6171fc1b
Updated documentation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shimniok 0:826c6171fc1b 1 #include "IncrementalEncoder.h"
shimniok 0:826c6171fc1b 2
shimniok 0:826c6171fc1b 3 IncrementalEncoder::IncrementalEncoder(PinName pin): _lastTicks(0), _ticks(0), _new(false), _interrupt(pin) {
shimniok 0:826c6171fc1b 4 _interrupt.mode(PullNone); // default is pulldown but my encoder board uses a pull-up and that just don't work
shimniok 0:826c6171fc1b 5 _interrupt.rise(this, &IncrementalEncoder::_incRise);
shimniok 0:826c6171fc1b 6 _interrupt.fall(this, &IncrementalEncoder::_incFall);
shimniok 0:826c6171fc1b 7 _t.start();
shimniok 0:826c6171fc1b 8 _t.reset();
shimniok 0:826c6171fc1b 9 _lastTime = _t.read_us();
shimniok 0:826c6171fc1b 10 }
shimniok 0:826c6171fc1b 11
shimniok 0:826c6171fc1b 12 unsigned int IncrementalEncoder::read() {
shimniok 0:826c6171fc1b 13 // disable interrupts?
shimniok 0:826c6171fc1b 14 unsigned int ticks = _ticks - _lastTicks;
shimniok 0:826c6171fc1b 15 _lastTicks = _ticks;
shimniok 0:826c6171fc1b 16 _new=false;
shimniok 0:826c6171fc1b 17 return ticks;
shimniok 0:826c6171fc1b 18 }
shimniok 0:826c6171fc1b 19
shimniok 0:826c6171fc1b 20 unsigned int IncrementalEncoder::readTotal() {
shimniok 0:826c6171fc1b 21 _new=false;
shimniok 0:826c6171fc1b 22 return _ticks;
shimniok 0:826c6171fc1b 23 }
shimniok 0:826c6171fc1b 24
shimniok 0:826c6171fc1b 25 unsigned int IncrementalEncoder::readRise() {
shimniok 0:826c6171fc1b 26 _new=false;
shimniok 0:826c6171fc1b 27 return _rise;
shimniok 0:826c6171fc1b 28 }
shimniok 0:826c6171fc1b 29
shimniok 0:826c6171fc1b 30 unsigned int IncrementalEncoder::readFall() {
shimniok 0:826c6171fc1b 31 _new=false;
shimniok 0:826c6171fc1b 32 return _fall;
shimniok 0:826c6171fc1b 33 }
shimniok 0:826c6171fc1b 34
shimniok 0:826c6171fc1b 35 unsigned int IncrementalEncoder::readTime() {
shimniok 0:826c6171fc1b 36 return _time;
shimniok 0:826c6171fc1b 37 }
shimniok 0:826c6171fc1b 38
shimniok 0:826c6171fc1b 39 void IncrementalEncoder::reset() {
shimniok 0:826c6171fc1b 40 _ticks = _lastTicks = 0;
shimniok 0:826c6171fc1b 41 }
shimniok 0:826c6171fc1b 42
shimniok 0:826c6171fc1b 43 void IncrementalEncoder::_increment() {
shimniok 0:826c6171fc1b 44 _ticks++;
shimniok 0:826c6171fc1b 45 }
shimniok 0:826c6171fc1b 46
shimniok 0:826c6171fc1b 47 #define A 0.3 // mix in how much from previous readings?
shimniok 0:826c6171fc1b 48 void IncrementalEncoder::_incRise() {
shimniok 0:826c6171fc1b 49 _rise++;
shimniok 0:826c6171fc1b 50 _ticks++;
shimniok 0:826c6171fc1b 51 _new=true;
shimniok 0:826c6171fc1b 52 // compute time between ticks; only do this for rise
shimniok 0:826c6171fc1b 53 // to eliminate jitter
shimniok 0:826c6171fc1b 54 int now = _t.read_us();
shimniok 0:826c6171fc1b 55 _time = A*_time + (1-A)*(now - _lastTime);
shimniok 0:826c6171fc1b 56 // Dead band: if _time > xxxx then turn off and wait until next tick
shimniok 0:826c6171fc1b 57 // to start up again
shimniok 0:826c6171fc1b 58 _lastTime = now;
shimniok 0:826c6171fc1b 59 }
shimniok 0:826c6171fc1b 60
shimniok 0:826c6171fc1b 61 void IncrementalEncoder::_incFall() {
shimniok 0:826c6171fc1b 62 _fall++;
shimniok 0:826c6171fc1b 63 _ticks++;
shimniok 0:826c6171fc1b 64 _new=true;
shimniok 0:826c6171fc1b 65 }