first re-commit.

pigpio-master/EXAMPLES/C/WIEGAND_CODE/wiegand.c

@@ -0,0 +1,137 @@
+#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);
+   }
+}
+