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#include <stdlib.h>
#include <pigpio.h>
#include "wiegand.h"
struct _Pi_Wieg_s
{
int mygpio_0;
int mygpio_1;
int mytimeout;
int in_code;
int bits;
Pi_Wieg_CB_t mycallback;
uint32_t num;
uint32_t code_timeout;
};
void _cb(int gpio, int level, uint32_t tick, void *user)
{
/*
Accumulate bits until both gpios 0 and 1 timeout.
*/
Pi_Wieg_t *wieg;
wieg = user;
if (level == 0) /* a falling edge indicates a new bit */
{
if (!wieg->in_code)
{
wieg->bits = 1;
wieg->num = 0;
wieg->in_code = 1;
wieg->code_timeout = 0;
gpioSetWatchdog(wieg->mygpio_0, wieg->mytimeout);
gpioSetWatchdog(wieg->mygpio_1, wieg->mytimeout);
}
else
{
wieg->bits++;
wieg->num <<= 1;
}
if (gpio == wieg->mygpio_0)
{
wieg->code_timeout &= 2; /* clear gpio 0 timeout */
}
else
{
wieg->code_timeout &= 1; /* clear gpio 1 timeout */
wieg->num |= 1;
}
}
else if (level == PI_TIMEOUT)
{
if (wieg->in_code)
{
if (gpio == wieg->mygpio_0)
{
wieg->code_timeout |= 1; /* timeout gpio 0 */
}
else
{
wieg->code_timeout |= 2; /* timeout gpio 1 */
}
if (wieg->code_timeout == 3) /* both gpios timed out */
{
gpioSetWatchdog(wieg->mygpio_0, 0);
gpioSetWatchdog(wieg->mygpio_1, 0);
wieg->in_code = 0;
(wieg->mycallback)(wieg->bits, wieg->num);
}
}
}
}
Pi_Wieg_t * Pi_Wieg(
int gpio_0,
int gpio_1,
Pi_Wieg_CB_t callback,
int timeout)
{
/*
Instantiate with the gpio for 0 (green wire), the gpio for 1
(white wire), the callback function, and the timeout in
milliseconds which indicates the end of a code.
The callback is passed the code length in bits and the value.
*/
Pi_Wieg_t *wieg;
wieg = malloc(sizeof(Pi_Wieg_t));
wieg->mygpio_0 = gpio_0;
wieg->mygpio_1 = gpio_1;
wieg->mycallback = callback;
wieg->mytimeout = timeout;
wieg->in_code = 0;
gpioSetMode(gpio_0, PI_INPUT);
gpioSetMode(gpio_1, PI_INPUT);
gpioSetPullUpDown(gpio_0, PI_PUD_UP);
gpioSetPullUpDown(gpio_1, PI_PUD_UP);
gpioSetAlertFuncEx(gpio_0, _cb, wieg);
gpioSetAlertFuncEx(gpio_1, _cb, wieg);
return wieg;
}
void Pi_Wieg_cancel(Pi_Wieg_t *wieg)
{
/*
Cancel the Wiegand decoder.
*/
if (wieg)
{
gpioSetAlertFunc(wieg->mygpio_0, 0);
gpioSetAlertFunc(wieg->mygpio_1, 0);
free(wieg);
}
}
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