flash.c

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/* FLASH.C - LED Flasher for the Forth EVA 167 Board with C167CR_2 Module */

#include <reg167.h>
#include <stdio.h>
#include <intrins.h>

unsigned int t2_count = 0;

void wait (unsigned long delay)  {     /* wait function */
unsigned long cl;
  for (cl=0; cl <= delay; cl++) 
      _nop_();
}

void main (void)  {
  unsigned int i;                     /* Delay var */
  unsigned int j;                     /* LED var */

  T2CON = 0x04;  // prescaler = fCPU/128
  T2IC  = 0x51;  // enable T2 Interrrut, IL=2, GL=1
  T2R   = 0;     // stop Timer 2
  IEN   = 1;     // global Interrupt enable

  DP2  = 0x00FF;
  ODP2 = 0x0000;

  // do not use printf for Simulated Serial Interface!!  
  printf("Sorry, no LEDs available on the Forth EVA 167 board..\n");

  while (1) {                         /* Loop forever */
    //T2R = 1;                          /* run Timer 2 */
    for (j=0x0100; j != 0; j<<=1){    /* Blink LED */
      P2 = ~j & 0x00FF;               /* Output to LED Port */
      for (i = 0; i < 10000; i++)  {  /* Delay for 10000 Counts */
        wait (0);                     /* call wait function */
      }
    }

    for (j=0x8000; j>0x0080; j>>=1){  /* Blink LED */
      P2 = ~j & 0x00FF;               /* Output to LED Port */
      for (i = 0; i < 10000; i++)  {  /* Delay for 10000 Counts */
        wait (0);                     /* call wait function */
      }
    }
  }
}

void T2_ISR (void) interrupt 0x22 {
  T2R = 0;                             /* stop Timer 2 */  
  T2 = 0;                              /* reset Timer 2 */
  P1L = 0;                             /* Output to LED Port */
  wait(0x10000);                       /* wait for some time */
  printf("\rTimer2 Interrupt counter: %04D",t2_count++);
  T2R = 1;                             /* Start Timer 2 */
}