16f628 newbie problem

[|Xne.3]

hello, i am new in the pic bussines and i have a problem. i use the 16f628a with an internal clock, a switch with an 10kohm resistant(pull down) on the RB0 - EXT_INT and a transistor to switch on a led.

the problem is that the systems works perfect when i pull my finger on the chip and it doesn't work when i give my hand away.

here is the source:

#include <16F628.h>
#use delay(clock=4000000)
#fuses INTRC_IO,NOWDT

#EXT_INT
void isr(){
output_high(PIN_B3);
delay_ms(500);



}


void main() {
ext_int_edge(H_TO_L); // init interrupt triggering for button press
enable_interrupts(INT_EXT);// turn on interrupts
enable_interrupts(GLOBAL);

set_tris_a(0);
set_tris_b(0b00000001); // RB0 wird als Eingang definiert



while (1)
{
delay_ms(500);
output_low(PIN_B3); //LED wird auf LOW gesetzt
delay_ms(500);
output_high(PIN_B3);

}
}


simple, but it doesn't work.


thanks for help!

[PCM programmer]

[Guest]

make sure your switch is held high and grounds when button pressed. i had a similar problem with a pic because i was letting the pins float and they would go high when a hand was waved near the circuit.