Ian Aherne / quadrature_decoder

driver for incremental encoder

decoder.cpp@5:1a5772466668, 2019-03-14 (annotated)

Committer:
ianaherne
Date:
Thu Mar 14 16:05:28 2019 +0000
Revision:
5:1a5772466668
Parent:
4:9913990cfd78
Child:
6:2fdce74d2a7b
addressed encoder issues and streamlined code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ianaherne 0:c3a05fe15b84 1 #include "decoder.h"
ianaherne 0:c3a05fe15b84 2
ianaherne 5:1a5772466668 3
ianaherne 5:1a5772466668 4
ianaherne 0:c3a05fe15b84 5 /**
ianaherne 0:c3a05fe15b84 6 * @brief constructor
ianaherne 0:c3a05fe15b84 7 * @details initializes interrupt on channel A, and initialises internal variables
ianaherne 0:c3a05fe15b84 8 * @param NA
ianaherne 0:c3a05fe15b84 9 * @return NA
ianaherne 0:c3a05fe15b84 10 * @warning interrupt functionallity on channel B is not used as it is not required.
ianaherne 0:c3a05fe15b84 11 *
ianaherne 0:c3a05fe15b84 12 */
ianaherne 0:c3a05fe15b84 13
ianaherne 0:c3a05fe15b84 14 decoder :: decoder(PinName channelA, PinName channelB):_channelA(channelA),_channelB(channelB) {
ianaherne 0:c3a05fe15b84 15
ianaherne 0:c3a05fe15b84 16 _channelA.rise(this, &decoder::isr);
ianaherne 4:9913990cfd78 17
ianaherne 0:c3a05fe15b84 18 _count = 0;
ianaherne 0:c3a05fe15b84 19 _direction = 0;
ianaherne 0:c3a05fe15b84 20
ianaherne 0:c3a05fe15b84 21 }
ianaherne 0:c3a05fe15b84 22
ianaherne 0:c3a05fe15b84 23 /**
ianaherne 0:c3a05fe15b84 24 * @brief isr
ianaherne 0:c3a05fe15b84 25 * @details interrupt servive routine to decode the encoder output
ianaherne 0:c3a05fe15b84 26 * @param NA
ianaherne 0:c3a05fe15b84 27 * @return NA
ianaherne 0:c3a05fe15b84 28 * @warning
ianaherne 0:c3a05fe15b84 29 *
ianaherne 0:c3a05fe15b84 30 */
ianaherne 0:c3a05fe15b84 31
ianaherne 0:c3a05fe15b84 32
ianaherne 0:c3a05fe15b84 33
ianaherne 0:c3a05fe15b84 34 void decoder :: isr(){
ianaherne 5:1a5772466668 35 //confirmed as x1 decoding y analysing waveform
ianaherne 4:9913990cfd78 36
ianaherne 0:c3a05fe15b84 37 uint8_t chA = _channelA.read();
ianaherne 4:9913990cfd78 38
ianaherne 0:c3a05fe15b84 39 uint8_t chB = _channelB.read();
ianaherne 0:c3a05fe15b84 40
ianaherne 0:c3a05fe15b84 41 if(chA == 1){
ianaherne 0:c3a05fe15b84 42
ianaherne 4:9913990cfd78 43 if(chB == 1){
ianaherne 4:9913990cfd78 44
ianaherne 4:9913990cfd78 45 if( _count != UPPER_LIMIT){
ianaherne 4:9913990cfd78 46 _count++;
ianaherne 4:9913990cfd78 47 }
ianaherne 4:9913990cfd78 48 _direction = 1;
ianaherne 5:1a5772466668 49
ianaherne 5:1a5772466668 50 //pc.printf(" 1 %d\n\n",_count);//debug
ianaherne 4:9913990cfd78 51
ianaherne 4:9913990cfd78 52 }
ianaherne 4:9913990cfd78 53
ianaherne 4:9913990cfd78 54
ianaherne 0:c3a05fe15b84 55
ianaherne 4:9913990cfd78 56 if(chB == 0){
ianaherne 4:9913990cfd78 57
ianaherne 4:9913990cfd78 58 if(_count != LOWER_LIMIT){
ianaherne 4:9913990cfd78 59 _count--;
ianaherne 4:9913990cfd78 60 }
ianaherne 4:9913990cfd78 61 _direction = 0;
ianaherne 4:9913990cfd78 62
ianaherne 5:1a5772466668 63 //pc.printf(" 0 %d\n\n",_count);//debug
ianaherne 5:1a5772466668 64
ianaherne 4:9913990cfd78 65 }
ianaherne 4:9913990cfd78 66
ianaherne 4:9913990cfd78 67 }
ianaherne 0:c3a05fe15b84 68
ianaherne 0:c3a05fe15b84 69 }
ianaherne 0:c3a05fe15b84 70
ianaherne 0:c3a05fe15b84 71 /**
ianaherne 0:c3a05fe15b84 72 * @brief getDirection()
ianaherne 0:c3a05fe15b84 73 * @details function to return the class private variable _direction
ianaherne 0:c3a05fe15b84 74 * @param NA
ianaherne 0:c3a05fe15b84 75 * @return the direction of encoder
ianaherne 0:c3a05fe15b84 76 * @warning
ianaherne 0:c3a05fe15b84 77 *
ianaherne 0:c3a05fe15b84 78 */
ianaherne 0:c3a05fe15b84 79
ianaherne 0:c3a05fe15b84 80 int8_t decoder :: getDirection(){
ianaherne 0:c3a05fe15b84 81
ianaherne 0:c3a05fe15b84 82 return _direction;
ianaherne 0:c3a05fe15b84 83
ianaherne 0:c3a05fe15b84 84
ianaherne 0:c3a05fe15b84 85
ianaherne 0:c3a05fe15b84 86 }
ianaherne 0:c3a05fe15b84 87
ianaherne 0:c3a05fe15b84 88 /**
ianaherne 0:c3a05fe15b84 89 * @brief getCount
ianaherne 0:c3a05fe15b84 90 * @details function to return the class private variable _count
ianaherne 0:c3a05fe15b84 91 * @param NA
ianaherne 0:c3a05fe15b84 92 * @return the number of turns of encoder +/-
ianaherne 0:c3a05fe15b84 93 * @warning
ianaherne 0:c3a05fe15b84 94 *
ianaherne 0:c3a05fe15b84 95 */
ianaherne 0:c3a05fe15b84 96
ianaherne 0:c3a05fe15b84 97 int16_t decoder :: getCount(){
ianaherne 0:c3a05fe15b84 98
ianaherne 0:c3a05fe15b84 99
ianaherne 0:c3a05fe15b84 100 return _count;
ianaherne 0:c3a05fe15b84 101
ianaherne 0:c3a05fe15b84 102 }
ianaherne 0:c3a05fe15b84 103
ianaherne 1:017efde7ab29 104 /**
ianaherne 1:017efde7ab29 105 * @brief reset()
ianaherne 1:017efde7ab29 106 * @details function to reset all internal counting and directional variables
ianaherne 1:017efde7ab29 107 * @param NA
ianaherne 1:017efde7ab29 108 * @return
ianaherne 1:017efde7ab29 109 * @warning
ianaherne 1:017efde7ab29 110 *
ianaherne 1:017efde7ab29 111 */
ianaherne 1:017efde7ab29 112
ianaherne 1:017efde7ab29 113 void decoder :: reset(){
ianaherne 1:017efde7ab29 114
ianaherne 4:9913990cfd78 115
ianaherne 1:017efde7ab29 116 _count = 0;
ianaherne 1:017efde7ab29 117 _direction = 0;
ianaherne 1:017efde7ab29 118
ianaherne 1:017efde7ab29 119 }
ianaherne 1:017efde7ab29 120