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| Author |
Message |
plzhelp
Guest
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| Controller Resetting |
 Posted: Mon Nov 27, 2006 5:38 am |
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Hi everyone
In my code the PIC16f877a is randomly resetting. here is the code
| Code: |
#include <16F877A.h>
#device *=16
#fuses HS,NOPROTECT,NOWDT,NOLVP
#use delay(clock=20000000)
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
#use rs232(baud=19200,xmit=pin_E1,rcv=pin_E2,parity=N,stream=pc)
//switch is on C0-->C3
int value,i;
void switch_read()
{
value = input_c();//use pull down resistors!!!
for(i=4;i<8;i++)
{
bit_clear(value,i);
}
fprintf(pc,"\n\ri read:%u",value);
}
void switch_write()
{
switch(value)
{
case 1:
output_c(0);
fprintf(pc,"\n\routput: 0");
break;
case 2:
output_c(1);
fprintf(pc,"\n\routput: 1");
break;
case 3:
output_c(2);
fprintf(pc,"\n\routput: 2");
break;
case 4:
output_c(3);
fprintf(pc,"\n\routput: 3");
break;
case 5:
output_c(4);
fprintf(pc,"\n\routput: 4");
break;
case 6:
output_c(5);
fprintf(pc,"\n\routput: 5");
break;
case 7:
output_c(6);
fprintf(pc,"\n\routput: 6");
break;
case 8:
output_c(7);
fprintf(pc,"\n\routput: 7");
break;
case 9:
output_c(8);
fprintf(pc,"\n\routput: 8");
break;
case 10:
output_c(9);
fprintf(pc,"\n\routput: 9");
break;
case 11:
output_c(10);
fprintf(pc,"\n\routput: 10");
break;
case 12:
output_c(11);
fprintf(pc,"\n\routput: 11");
break;
}
}
void main()
{
setup_adc( ADC_OFF );
fprintf(pc,"\n\rstart\n\r");
while(1)
{
output_low(pin_E0);
delay_ms(40);
switch_read();
output_high(pin_E0);
delay_ms(40);
switch_write();
delay_ms(3000);
}
}
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I have also noticed that when i comment out the 'switch_write()' funtion then the controller does not reset.
Dont quite know whats going on
Many thanx |
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Ttelmah
Guest
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| Posted: Mon Nov 27, 2006 6:27 am |
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Realistically, probably electrical noise. What does output_c actually drive?. What suppression have you got close to the PIC?. How is your supply generated?. There is nothing in the code that wll itself 'cause' a reset.
However as a seperate comment, why store the same thing multiple times?.
| Code: |
void switch_write(void) {
output_c(--value);
fprintf(pc,"\n\routput: %d",value);
}
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Is a hell of a lot simpler...
Best Wishes |
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tsupuntu
Joined: 05 May 2006
Posts: 9
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| EMI/EMC |
| Posted: Mon Nov 27, 2006 10:59 am |
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| I think Reset from trace PCB of your.You should learning Electromagnetic EMI/EMC |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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SET
Joined: 15 Nov 2005
Posts: 161
Location: Glasgow, UK
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| Posted: Mon Nov 27, 2006 1:36 pm |
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| Cant see exactly what you are doing - but it does look like you read Port C, and then in 'switch_write' you write back out to Port C. But if you have pressed a switch and the output wants to go the opposite way then the processor will likely reset? |
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