/* gpiointr.c
   This program does the following: 
   - Creates a GPIO session with error checking
   - Installs an interrupt handler and enables EIR interrupts
   - Waits for EIR; invokes the handler for each interrupt
*/

#include <stdio.h>
#include <sicl.h>

void SICLCALLBACK handler(INST id, long reason, long sec)
{
   if (reason == I_INTR_GPIO_EIR) {
      printf("EIR interrupt detected\n");
      
     /* Proper protocol is for the peripheral device to hold
      * EIR asserted until the controller "acknowledges" the
      * interrupt.  The method for acknowledging and/or responding
      * to EIR is very device-dependent.  Perhaps a CTLx line is 
      * pulsed, or data is read, etc.  The response should be
      * executed at this point in the program.
      */
   }
   else
      printf("Unexpected Interrupt; reason=%d\n", reason);
}

main()
{
   INST intf;     /* interface session id */

   #if defined (__BORLANDC__) && !defined (__WIN32__)
      _InitEasyWin();  /* required for Borland EasyWin programs */
   #endif

   /* log message and exit program on error */
   ionerror(I_ERROR_EXIT);

   /* open GPIO interface session */
   intf = iopen("gpio");

   /* suspend interrupts until configured */
   iintroff();

   /* configure interrupts */
   ionintr(intf, handler);
   isetintr(intf, I_INTR_GPIO_EIR, 1);

   /* wait for interrupts */
   printf("Ready for interrupts\n");
   while (1) {
      iwaithdlr(0);  /* optional timeout can be specified here */
   }

   /* iwaithdlr performs an automatic iintron().  If your program
    * does concurrent processing, instead of waiting, then you need
    * to execute iintron() when you are ready for interrupts.
    */

   /* This simplified example loops forever.  Most real applications
    * would have termination conditions that cause the loop to exit.
    */
   iclose(intf);

   /* For WIN16 applications, call _siclcleanup before exiting to release
      resources allocated by SICL for this application.  This call
      is a no-op for WIN32 applications.
   */
   _siclcleanup();

   return 0;
}