INTERRUPTS

[fariq23]

Situation
1. Pic will continuously toggle LED at PORT RB1, RB2 and RB3, and toggle
buzzer ON and OFF in sequence every 1 sec.

2. When interrupt occur, ALL LED and buzzer will automatically turn
OFF, and only turn ON LED RB4.

3. After 2 sec, all sequence function back as normal.

Buzzer Q1-RD0
Buzzer GND-GND

[asmallri]

It's homework time again...
_________________
Regards, Andrew

http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!!

[fariq23]

hmm...i had a problem..that why i post in this forum..
i need and idea not a useless comment!!!!

[Ttelmah]

Stop and think for a moment.
You want your interrupt to do something. So, why is there nothing in your interrupt handler?.
You need the handler to trigger the new operation you want.
Unfortunately, if you put a delay in your interrupt handler, the response to the button will become terrible (do a search here to find out 'why'.... :-(

Approach things differently:

Have a global 'state' variable.
Have a timer running. Have this incrementing or decrementing a tick variable, at some suitable interval (say 50*/sec).
Then in your main code, have a 'state machine'. The code sits looping _quickly_, without any delays. When the tick counter gets to a particular value, you increment to the next 'state', which changes the lights as required, and sets the new tick count required (so with a 50Hz tick, and wanting 1 second, 50 for example). When the state gets to the last normal state, you reset it, giving you your loop.
Then have your edge detector, change the state variable, to a new value beyond the normal range, and set a new tick. This works just like the main state machine, sequencing through the operations you want as a result of the interrupt, and when these have all finished, _resetting_ the state variable to the start of the main loop.
As a general comment, try to avoid 'goto' loops. While _occasionally_ useful, their operation can be done more safely, using a 'while', and with less likelyhood of getting confused....

Best Wishes

[bkamen]

Let's break this down step by step...

Setup stuff..

[fariq23]

#include <16f877a.h>
#use delay(clock = 20000000)
#fuses hs, noprotect, nowdt, nolvp
#byte PORTB=6

#INT_EXT
void switch_isr(){
portb=0b00010000;
output_bit(pin_D0,0);
delay_ms(2000);
}

void main ()
{

set_tris_b(0b00000001);
enable_interrupts(GLOBAL);
enable_interrupts(INT_EXT);
ext_int_edge(H_TO_L);

output_bit( PIN_B1 ,1);
delay_ms(1000);
output_bit( PIN_B2 ,1);
delay_ms(1000);
output_bit( PIN_B3 ,1);
delay_ms(1000);
output_bit( PIN_D0 ,1);
delay_ms(1000);
output_bit( PIN_D0 ,0);
delay_ms(1000);
}
}While(1);



am i right with this condition??

[bkamen]

Well, yes and no.

It's bad form to use anything that purposefully passes time in an ISR (like delay_ms).

Not that it can't be done... but you will learn that optimally, it's best to set a flag in the ISR and then let main() see the flag change and then execute some commands based on that flag condition (resetting the flag at the end).

What you have would work -- but down the road is not a recommended method. (because of the delay_ms() in your ISR)

Did you try it? Does it work?

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[Ttelmah]

and, 'how long does it take to respond'.

Fourth line of my post....

Best Wishes

[bkamen]

Ha! Ttelmah and I posting at the same time.

When I was writing my post, you hadn't posted yet.
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[fariq23]

but my condition, i want interrupts take an action for 2 second..
and then continue back the main routine..i read the datasheet about interrupt.
it explain the another subroutine will take over when interrupts occur and after a few moment it will continue where it was stop..

i'm not try the coding yet because i'm do not have kit to test the program..

[bkamen]

[fariq23]

thanks bkmen..i will try to test my program on hardware..
but i need your suggestion where the part of my coding is totally wrong and the part that best part to put and interrupts subroutine..
thank for your cooperation...

[bkamen]

As Ttelmah said, you need something like this:

[fariq23]

thanks bkamen..