mirror of https://github.com/joan2937/pigpio
95 lines
1.9 KiB
C
95 lines
1.9 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <pigpio.h>
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#include "rotary_encoder.h"
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struct _Pi_Renc_s
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{
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int gpioA;
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int gpioB;
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Pi_Renc_CB_t callback;
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int levA;
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int levB;
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int lastGpio;
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};
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/*
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+---------+ +---------+ 0
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A | | | |
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+---------+ +---------+ +----- 1
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+---------+ +---------+ 0
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B | | | |
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----+ +---------+ +---------+ 1
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*/
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static void _cb(int gpio, int level, uint32_t tick, void *user)
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{
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Pi_Renc_t *renc;
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renc = user;
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if (gpio == renc->gpioA) renc->levA = level; else renc->levB = level;
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if (gpio != renc->lastGpio) /* debounce */
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{
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renc->lastGpio = gpio;
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if ((gpio == renc->gpioA) && (level == 1))
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{
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if (renc->levB) (renc->callback)(1);
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}
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else if ((gpio == renc->gpioB) && (level == 1))
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{
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if (renc->levA) (renc->callback)(-1);
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}
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}
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}
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Pi_Renc_t * Pi_Renc(int gpioA, int gpioB, Pi_Renc_CB_t callback)
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{
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Pi_Renc_t *renc;
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renc = malloc(sizeof(Pi_Renc_t));
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renc->gpioA = gpioA;
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renc->gpioB = gpioB;
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renc->callback = callback;
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renc->levA=0;
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renc->levB=0;
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renc->lastGpio = -1;
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gpioSetMode(gpioA, PI_INPUT);
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gpioSetMode(gpioB, PI_INPUT);
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/* pull up is needed as encoder common is grounded */
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gpioSetPullUpDown(gpioA, PI_PUD_UP);
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gpioSetPullUpDown(gpioB, PI_PUD_UP);
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/* monitor encoder level changes */
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gpioSetAlertFuncEx(gpioA, _cb, renc);
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gpioSetAlertFuncEx(gpioB, _cb, renc);
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}
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void Pi_Renc_cancel(Pi_Renc_t *renc)
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{
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if (renc)
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{
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gpioSetAlertFunc(renc->gpioA, 0);
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gpioSetAlertFunc(renc->gpioB, 0);
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free(renc);
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}
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}
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