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Timed getchar() using INT_TIMER1 ISR

 
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DaveKush



Joined: 10 Jan 2006
Posts: 6

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Timed getchar() using INT_TIMER1 ISR
PostPosted: Thu Jan 12, 2006 12:10 pm     Reply with quote

Guys, do you know of any way to do a getchar() with a timeout occurring if no characters are received? In my code, I'm using INT_TIMER1 to track 1 second intervals, but when I call the soft serial read function, flow transfers to the ISR INT_TIMER1 and never returns. I'm guessing that this has something to do with the interrupts being disabled during a getchar(), but I can't figure out the work-a-round trick.

PIC18f6585, CCS: PCH version 3.218

Code:

#INT_TIMER1                       
void clock_isr() {                                           
  if(--int_count==0) {         
    ++seconds;
    int_count = INTS_PER_SECOND;
  }
}

#use rs232 (baud=9600, rcv=RS232_TO_MB_RCV)
int read_soft_serial(void) {
  while (seconds < 10) {
    getchar();
  }
}


while (1) {
  set_timer1(0);
  seconds = 0;
  result = read_soft_serial()
}
[/code]
DaveKush



Joined: 10 Jan 2006
Posts: 6

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PostPosted: Thu Jan 12, 2006 12:49 pm     Reply with quote

OK, forget it. I figured it out. kbhit() is your friend!

Dave
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Jan 12, 2006 1:03 pm     Reply with quote

Also look at the timed_getc() function in the CCS example file EX_TGETC.C
It's in this folder:
c:\program files\picc\examples
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