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