INTERRUPT PROGRAMMING

[mohdismiaswaly]

Hello,

I am searching if there any project in the Cytron's website that has interrupt programming code? I am using PIC18F4550 chip. I am connecting pin RB0 with push button switch and pin RB7 with LED. Currently, I am blinking the LED (pin RB7) non stop. So, I would like to introduce interrupt program inside the existing program so that when I push the button switch (pin RB0), the LED will stop blinking.

Any idea?

Thanks

[shahrul]

Open PIC18F4550 datasheet, search address INTCON. See at bit 4 of the address, INT0IE: INT0 External Interrupt Enable bit.

[mohdismiaswaly]

So I just need to enable that bit into that register?

That's all?

TQ

[shahrul]

Enable Interrupt bit and add Interrupt function.

[mohdismiaswaly]

Hello Mr.Shahrul,

Can you share with me a simple code under interrupt function in c language?
I just want to test the functionality of interrupt programming.

Thanks in advance..

[Brian Griffin]

For example, if you need to have timer0 interrupts, you have to enable the bit in the INTCON register, which is the TMR0IE, and then afterwards switch on the timer0 in T0CON register.

So, you can do this:

CODE: SELECT_ALL_CODE


INTCON.TMR0IF = 0;
INTCON.TMR0IE = 1;

T0CON.TMR0ON = 1;
//other code for setting timer0 here, like prescale and stuff

INTCON.GIE = 1;



You have to do this also, depending on the compiler, you should include a place for the interrupt to jump into when the interrupt flag is up:

CODE: SELECT_ALL_CODE

void interrupt() {

if(INTCON.TMR0IF)
{
   
   // do something here, like reload the timer0 or something.
   INTCON.TMR0IF = 0;  // clear flag.

}

}



Different C compilers for microcontrollers have their own method of handling interrupts. But the concept remains the same.

[khairul]

Hai, sorry to INTERUPT... i have a problem regarding with UART and TIMER, i have a code to transmit a serial data to a module and wait for the module to return a packet of data back..

My problem is the coding just wait forever until the packet of data received to the pic due to this coding line
"

CODE: SELECT_ALL_CODE

while(PIR1bits.RCIF==0); //wait for data to received

". and i just want it to wait for a while, if there is no data then leave from the task.

So my solution (if it is possible) is to create a TIMER to wait for a while and at the same time waiting for the packet of data to be received and eventually when the timer is off, i just create a code to jump back to the main.

So it is possible to create code like that?

[shahrul]

Hai, sorry to INTERUPT... i have a problem regarding with UART and TIMER, i have a code to transmit a serial data to a module and wait for the module to return a packet of data back..

My problem is the coding just wait forever until the packet of data received to the pic due to this coding line
"

CODE: SELECT_ALL_CODE

while(PIR1bits.RCIF==0); //wait for data to received

". and i just want it to wait for a while, if there is no data then leave from the task.

So my solution (if it is possible) is to create a TIMER to wait for a while and at the same time waiting for the packet of data to be received and eventually when the timer is off, i just create a code to jump back to the main.

So it is possible to create code like that?

This is need to use UART Interrupt. PIC not waiting for the UART data. It will remain run main program, when UART data comes in, PIC automatically read UART. So, PIC not wasting time to waiting for the data.

[khairul]

ok, i will look on that... if i cannot solve it, i post again.. tq all especially En.Shahrul for helping me.