[solved]PIC timer interrupt simple question

[wcgan]

pic timer interrupt

Hi all,

I have tried the code below to generate an interrupt after timer1 overflow. but it does not working.

Can anyone help to correct my code? or give me a simple example of timer interrrupt?

thanks.

#include <timers.h>
#include <p18cxxx.h>

void timer1_isr(void);

void main()
{
	TRISD = 0x00;	// RD4-7 for LCD, RD3 for SR_DATdA, RD2 for output to CPLD, RD0 for nRESET output 
	LATD = 0xFF;
	PORTD = 0xFF; // RESET alwasy high at power up		
	PORTEbits.RDPU =0;

	OpenTimer1(TIMER_INT_ON & T1_8BIT_RW & T1_SOURCE_INT & T1_PS_1_8 & T1_OSC1EN_OFF & T1_SYNC_EXT_OFF);
	WriteTimer1(0x00FF);

	RCONbits.IPEN=1;
	RCONbits.SBOREN=0;

	INTCON=0b10000000;
	IPR1bits.TMR1IP=1;
	PIE1bits.TMR1IE=1;

	while(1)
	{
	}
}

void high_ISR (void)
{
_asm goto timer1_isr _endasm
}

#pragma interrupt timer1_isr

void timer1_isr(void)
{
PIR1bits.TMR1IF=0;
WriteTimer1(0x00FF);

PORTDbits.RD7=~PORTDbits.RD7;
}

 

[shashavali_m]

mcc18 timer1 library

Just Check T1CON register value..What values it has written when u use Library function....When we use library function, we need define define MASK Value..just go through it library document...please let me know if u have not succeeded ...i am wrking in microchip..i can help

 

[umery2k75]

#pragma code high_vector

Make sure, global interrupt is enable.

 

[wcgan]

mcc18 opentimer1

Just Check T1CON register value..What values it has written when u use Library function....When we use library function, we need define define MASK Value..just go through it library document...please let me know if u have not succeeded ...i am wrking in microchip..i can help

Hi shashavali_m,

after OpenTimer1(...), T1CON value was 0x35

Make sure, global interrupt is enable.

Hi umery2k75,
I already set the global interrupt to enable.
INTCON=0b10000000;
INTCON.7 = GIE/GIEH: Global Interrupt Enable bit.

thanks.

Added after 4 hours 20 minutes:

Hi all,

I found another example and it is working. But i still have some problem on the interrupt sub-routine.

my board using ext resonator : 4Mhz

below are the code:

#include <p18f4550.h>

void timer1_isr(void); //Interrupt service routine prototype
int i; //Global counter
//Always include this code, it’s necessary when using a bootloader
extern void _startup (void);

#pragma code _RESET_INTERRUPT_VECTOR = 0x000800
void _reset (void)
{
_asm goto _startup _endasm
}
#pragma code

#pragma code high_vector = 0x000808
void high_ISR (void)
{
_asm goto timer1_isr _endasm
}
#pragma code

#pragma code _LOW_INTERRUPT_VECTOR = 0x000818
void low_ISR (void)
{
;
}
#pragma code

//End bootloader code

#pragma interrupt timer1_isr //High priority interrupt service routine
void timer1_isr(void)
{
	PIR1bits.TMR1IF = 0; //Reset Timer1 interrupt flag
	TMR1H = 0x00;
	TMR1L = 0x01;
	i = i++ % 64;  // this is line is from the original sample
	PORTAbits.RA0 = ~PORTAbits.RA0;
}
#pragma code


void main(void)
{
	TRISA = 0x00; //Port A output
	LATA=0xFF;
	ADCON1 = 0b00001111; //All ADC disabled
	RCONbits.IPEN = 1; //Enable priority levels on interrupts
	RCONbits.SBOREN = 0; //Disable BOR
	TMR1H = 0x00;
	TMR1L = 0x01;
	T1CON = 0b00110001; //Timer1 settings: 1:8 prescalar, clock = Fosc/4, Timer1 ON
	INTCONbits.GIE = 1; //Enable global interrupts
	INTCONbits.PEIE = 1; //Enable peripheral interrupts
	INTCON = 0b10000000; //
	IPR1bits.TMR1IP = 1; //Timer1 interrupt priority high
	PIE1bits.TMR1IE = 1; //Timer1 interrupt enable

	while(1)
	{
	}
}

The problem is, if i comment "i = i++ % 64;" in 'timer1_isr' sub-routine, main program will not able to trigger/jump in the interrupt "timer1_isr" function again. leave the "i = i++ % 64;" in 'timer1_isr' then everything is ok.

anyone can tell me what going on in this program?

Please find attached for my project configuration bits.
Thanks

/*===================================================
Hi all,

I found out what is the problem in my program already.
I set the wrong interrupt vector
#pragma code high_vector = 0x000808
#pragma code _LOW_INTERRUPT_VECTOR = 0x000818
the correct interrupt vector should be
#pragma code high_vector = 0x000008
#pragma code _LOW_INTERRUPT_VECTOR = 0x000018

thanks.