problem in pic16f877a interrupt(reset the microcontroller when INTCON = 0xC0)

D

deepa.malagi

New Member

• Jun 21, 2011

• #1

Hello everybody,

I am using pic16f877a ic,

I am getting problem in interrupt(all peripheral interrupt).
I tried UART interrupt & timer1 interrupt
but there is same problem in these interrupt, i.e micro controller resting continually when I assign INTCON = 0xc0.

Please help me to sort out this problem,if possible give me example code for Timer1 imterrupt.

 

ericgibbs

Well-Known Member

Most Helpful Member

• Jun 21, 2011

• #2

hi,
Post or Attach your full program.

 

D

deepa.malagi

New Member

• Jun 21, 2011

• #3

Code:

unsigned int Timer_1_Reload = 62500;
void Timer_int(void)
{

    T1CON = 0x30;        // 0011 0000, 1:8 prescalar, disable timer-1
    TRISC = 0x00;
    TMR1H = (unsigned char)(Timer_1_Reload >> 8);
    TMR1L = (unsigned char)Timer_1_Reload;
    
    INTCON = 0xC0;              // Enable interrupt (bits GIE and PEIE)
    TMR1IF = 0;
    PIE1 |=    0x01;
    T1CON |= 0x01;

}    
    
void interrupt_isr(void)
{
    unsigned int Timer_1_Reload = 62500;
    if(PIR1 & TMR1IF)
    {
        //INTCON = 0xC0;
        PORTC = 0x01;
        TMR1H = (unsigned char)(Timer_1_Reload >> 8);
        TMR1L = (unsigned char)Timer_1_Reload;
        TMR1IF = 0;
    }
    PORTC |= 0x02;
}

This is my code please help me to sort out the problem.

 

Last edited by a moderator: Jun 21, 2011

3v0

Coop Build Coordinator

Forum Supporter

• Jun 21, 2011

• #4

Please use code tags [ code] ....program... [ /code]

Where is your main() function ? As ericgibbs said we need to see the entire program.

We only have one interrupt vector so what it the purpose of void Timer_int(void); ?

As ericgibbs said we need to see the entire program!

 

Last edited: Jun 21, 2011

D

deepa.malagi

New Member

• Jun 21, 2011

• #5

please find the full code attache with this mail

 

Attachments

• New Folder (4).zip

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3v0

Coop Build Coordinator

Forum Supporter

• Jun 21, 2011

• #6

I got your timer 1 interrupt working in MPLAB SIM.

First
void interrupt_isr(void)

needs to be
void interrupt isr(void)

Second
you need to turn on the interrupts outside the ISR for the ISR to be used
so putting
INTCON = 0xC0;
will not enable interrupts. Instead I used this line

Code:

//    Initialize_UART1();   /// removed this file for testing as it has redundant code
    PORTA = 0x01;
    Timer_int();
    INTCON = 0xC1;  //// added this

I do not care for
INTCON = 0xC1;
I would much rather see several lines like these bases on the bit name in the p16F877A.h file. That way everyone can see what is going on by looking at the code.
INTCONbits.TMR0IF = 1;
INTCONbits.GIE = 1;

Lastly use a __config line to set the fuses. That way you and everyone else know what they are without looking at you MPLAB project file.

Code:

#include <pic.h>
 __CONFIG(DEBUG_ON & FOSC_HS & WDTE_OFF & LVP_OFF );
#include "UART.h"
#include "TIMER.h"

Much of the code is still a mess. You need to take you time an look at the processor datasheet and examples. When you UNDERSTAND the code use the concepts and bits of code. Just copy and pasting does not cut it.

 

Attachments

• display_board.zip

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P

Pommie

Well-Known Member

Most Helpful Member

• Jun 21, 2011

• #7

Ignore me.

Mike.

 

Last edited: Jun 21, 2011

D

deepa.malagi

New Member

• Jun 21, 2011

• #8

thank u, i ll try this.

 

D

deepa.malagi

New Member

• Jun 22, 2011

• #9

I tried this debug mode for 2 ,3 it times worked fine, but after that when I restart the Micro controller, it is not at all executing the main() function ,directly moving to the interrupt subroutine for any 1 time.
I tried the same program in simulation mode I am getting the error:

CORE-E0002: Stack under flow error occurred from instruction at 0x00001d

please help me.

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jun 22, 2011

• #10

You seem to be using timer1 but enable both timer1 and timer0 interrupts. Which compiler are you using?

Mike.

 

D

deepa.malagi

New Member

• Jun 22, 2011

• #11

no I am not enabled the timer 0 interrupt,only timer1 is enabled,

& I am using hi tech c compiler.

 

3v0

Coop Build Coordinator

Forum Supporter

• Jun 22, 2011

• #12

Your code is a mess. You need to either start over or go though and understand what every line does, know why you are setting or clearing each bit of the SFR's.

That sounds like a lot, but it is the nature of programming micro controllers.

 

D

deepa.malagi

New Member

• Jun 22, 2011

• #13

I wrote separate code for timer interrupt, even in this also i am facing the same problem
its not executing the main function,(directly going to interrupt & then while(1) loop )

please find the code attached with this mail,

please help to sort out the problem.

 

Attachments

• 16f877_timer_interrupt.zip

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P

Pommie

Well-Known Member

Most Helpful Member

• Jun 22, 2011

• #14

Your code works fine in the simulator. However, if(PIR1 & TMR1IF) should be if(TMR1IF). I'm not sure what the compiler would do anding a char with a bit.

Mike.

 

D

deepa.malagi

New Member

• Jun 22, 2011

• #15

i tried this code in simulator, I am getting error
CORE-E0002: Stack under flow error occurred from instruction at 0x00001c

in which compiler u tried this?

please put break point in the main after the instruction T1CON = 0x30;
please see weather main function is executing.

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jun 22, 2011

• #16

I am using HI-TECH C PRO for the PIC10/12/16 MCU family (Lite) V9.65PL1 and I can single step all the way to main. The interrupt occurs every 24,332 cycles.

Mike.

 

D

deepa.malagi

New Member

• Jun 23, 2011

• #17

thank u it is working...

thank u.

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jun 25, 2011

• #18

It's customary to explain what the problem was so that anyone reading this in the future may be able to solve their problem.

Mike.

 

D

deepa.malagi

New Member

• Jun 27, 2011

• #19

Hi,

My problem got solved.
The issue was with the version of Hi-Tech c compiler (version 9.60) that i was using.
Once i installed latest version 9.80 the problem got solved.

Thanks again for the timely help.

Thanks & regards,
Deepa.