View previous topic :: View next topic |
Author |
Message |
Guest
|
Simple RB0 interrupt (#int_ext) |
Posted: Thu May 12, 2005 6:12 pm |
|
|
I am learning PIC C, I try to work with external interrupt. I can't not get it to work. Can any body help?
here is my code:
Code: |
#include <18F452.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
/*
*LED connect to RB1 is active low (0=ON, 1=OFF)
*/
//Start interrupt subroutine.
#int_ext //Set external interrupt on pin RB0
void ISR()
{
output_low(pin_b1); // when RB0 is low turn on LED
}
// End Interrupt routine
//Main program start here
void main()
{
output_b(0x00);
set_tris_b(0x01); // Set RB0 to input, RB1-7 output
ext_int_edge(H_TO_L); // init interrupt triggering for button press
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
while (1) // keep LED off.
{
output_high(pin_b1);
}
}
|
I am looking forward to hear from soon.
Thanks.... |
|
![](templates/subSilver/images/spacer.gif) |
iso9001
Joined: 02 Dec 2003 Posts: 262
|
|
Posted: Thu May 12, 2005 9:24 pm |
|
|
You are going back to the while() and then the output_high so fast I'm guessing you are just not seeing it.
Holding the int pin low will not hold the LED on if that is what you were thinking.
try
Code: |
void main()
{
output_b(0x00);
set_tris_b(0x01); // Set RB0 to input, RB1-7 output
ext_int_edge(H_TO_L); // init interrupt triggering for button press
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
output_high(pin_b1);
while (1) // keep LED off.
{
}
}
|
With that the led should turn on when the int is driven low. |
|
![](templates/subSilver/images/spacer.gif) |
Guest
|
Interrupt |
Posted: Mon May 16, 2005 10:41 am |
|
|
I have tried that and it does not respond to the RBO sw. When the sw=0,
it does not turn on the LED on pin_b1. Anyone has a sample code for interrupt to do this simple interrupt? I have read the example came with
the manual, but I do not get it, I am may be too new to PIC.
Please help..... |
|
![](templates/subSilver/images/spacer.gif) |
John P
Joined: 17 Sep 2003 Posts: 331
|
|
Posted: Mon May 16, 2005 11:48 am |
|
|
Try adding a delay to the interrupt so it has time to let you see the light before returning to the main program. See addition:
Code: |
#include <18F452.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
/*
*LED connect to RB1 is active low (0=ON, 1=OFF)
*/
//Start interrupt subroutine.
#int_ext //Set external interrupt on pin RB0
void ISR()
{
output_low(pin_b1); // when RB0 is low turn on LED
delay_ms(200); // Wait 0.2 second with light on before returning
}
// End Interrupt routine
//Main program start here
void main()
{
output_b(0x00);
set_tris_b(0x01); // Set RB0 to input, RB1-7 output
ext_int_edge(H_TO_L); // init interrupt triggering for button press
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
while (1) // keep LED off.
{
output_high(pin_b1);
}
}
|
|
|
![](templates/subSilver/images/spacer.gif) |
iso9001
Joined: 02 Dec 2003 Posts: 262
|
|
Posted: Mon May 16, 2005 11:49 am |
|
|
Exactly, When I posted I only posted the part you needed to change, and even then it was a single shot switch, |
|
![](templates/subSilver/images/spacer.gif) |
sseidman
Joined: 14 Mar 2005 Posts: 159
|
|
Posted: Mon May 16, 2005 1:38 pm |
|
|
John P wrote: | Try adding a delay to the interrupt so it has time to let you see the light before returning to the main program. |
Putting 200ms delays in interrupt routines is a habit best left undeveloped.
Scott |
|
![](templates/subSilver/images/spacer.gif) |
PCM programmer
Joined: 06 Sep 2003 Posts: 21708
|
|
![](templates/subSilver/images/spacer.gif) |
Guest
|
interrupt |
Posted: Mon May 16, 2005 2:43 pm |
|
|
Thanks....
I got it working, somehow the SW on RB0 of my demo 2 plus board does
not work, that's why I didn't see it. But actually the software is working fine. |
|
![](templates/subSilver/images/spacer.gif) |
|