Problem Using External Interrupt

[leels]

Hello All...

I am having a bit of problem trying to use the external interrupt on a PIC16F873A. I have the external interrupt port (pin b0) connected to the battery through a push button and a pull up resistor (15K) to the ground. I'm using the following routine to toggle a led everytime the pushbutton is activated.

#int_ext
void pushbutton_isr()
{
if(TransposeOn == 0)
{
output_high(LED_OUT_1);
TransposeOn = 1;
}
else if(TransposeOn == 1)
{
output_low(LED_OUT_1);
TransposeOn = 0;
}
}

I'm also using the following enables for the interrupts...

enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);


Now the problem is, the interrupt routine only seems to be working ONCE. So the first time I activate the pushbutton, the led lights but then any subsequent activation of the pushbutton does not seem to run the intrrupt service routine. So the led stays on.

[PCM programmer]

Do you have a continuous loop after you enable interrupts ?
If not, add one as shown in bold below:

[kender]

[leels]

1) I have a do{ }while(true) loop in the code.

2) Thank you for correcting the typo kender. It is a pull-down resistor connected between the pin b0 and ground. I'm quite sure that the circuit is correct. When I push the butteon, pin b0 gets high. When the button is not activated, the pin b0 stays low.

The datasheet for the controller mentions that the interrupt flag bit needs to be cleared by the code. Would this be a case? and how would I go about doing that?

Thanks for your help

[PCM programmer]

Here's an example program that might help:
http://www.ccsinfo.com/forum/viewtopic.php?t=17041&start=1

[kender]

You might also find this thread on debouncing a switch useful
http://www.ccsinfo.com/forum/viewtopic.php?t=24103

[leels]

Thank you PCM programmer and kender.
The interrupt now works flawlessly.