I've tried this on 12C509A and 16F877 with the same result. I'm just looping
forever reading two pins and sending a text on RS-232. I'm using CCS
compiler for coding.

   while (-1){
      if (INPUT(PIN_B3)){
         printf("B3 High\n\r");
      } else {
         printf("B3 Low\n\r");}
      delay_ms(250);

      if (INPUT(PIN_B4)){
         printf("B4 High\n\r");
      } else {
         printf("B4 Low\n\r");}
      delay_ms(250);
   }

Pin B3 gets a logic 1 (4.95V) or 0 (0.01V) and pin B4 is always high. The
input to B3 comes from a Hall-effect switch. When it detects a magnet it
gows low and when magnet is removed it goes, of course, high again (pull-up
to +5V and the Hall acts like a transistor driving to ground). The logic
output is OK all the time.

When removing the magnet so it goes high again the PIC is dead. But not
compleatly dead! If I add the magnet again so it goes low the PIC continues
from where it was again.

Anyone having some hints or ideas? I'm very confused now :-)

/Johan

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements