I'm programming a PIC18F452 microcontroller, using CCS C Compiler. I have to regulate the interrupt levels of external interrupt 0,1,2 and timer 0 interrupt. Timer0 interrupt will be the lowest one and external interrupt 2 is the highest one. The high level interrupt vector is at 000008h and low priority interrupt vector is at 000018h. Can anyone give some information about how can i set priority levels of interrupts with C language.
Thanks!

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--- In , Eirik Karlsen <eikarlse@o...> wrote: > In that vector you need polling to find out which device caused the > interrupt. > Well, that's the way I was doing it before, but having different priority interrupts has the benefit that you don't have to do that anymore (unless you have multiple sources for the same priority, which I don't.)

> You need to set the IPEN bit in the RCON REGISTER to > enable interrupt priority levels. Ah! I knew there was something I was forgetting. Thanks, I'm sure it will fix things.

In that vector you need polling to find out which device caused the interrupt.

john wrote:

--- In p...@yahoogroups.com, "Vecheslav Silagadze"
<uwobjectivist@h...> wrote:
>
> Oh, I should mention the chip is PIC18F458 and the high vector is
> 0x08, and the low vector is 0x18
>
> --- In p...@yahoogroups.com, "Vecheslav Silagadze"
> <uwobjectivist@h...> wrote:
> >
> > I've setup two interrupt routines. One for a timer and one for
I2C.
> > It seems both are sent to the high priority vector even though I
> > setup the I2C as low priority.
> >
> > here's the relevant part of the code
> >
> > //Configure interrupts
> > INTCON2bits.TMR0IP = 1; //set timer0 interrupt at high priority
> > IPR1bits.TMR1IP = 1; //set timer1 interrupt at high priority
> > PIE1bits.SSPIE = 1; //enable MSSP interrupts
> > IPR1bits.SSPIP = 0; //set MSSP interrupt as low priority
> > INTCONbits.GIE = 1; //global interrupts enable
> >
> > can anyone help me out here?
You need to set the IPEN bit in the RCON REGISTER to
enable interrupt priority levels.

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--- In , "Vecheslav Silagadze" <uwobjectivist@h...> wrote: > > Oh, I should mention the chip is PIC18F458 and the high vector is > 0x08, and the low vector is 0x18 > > --- In , "Vecheslav Silagadze" > <uwobjectivist@h...> wrote: > > > > I've setup two interrupt routines. One for a timer and one for I2C. > > It seems both are sent to the high priority vector even though I > > setup the I2C as low priority. > > > > here's the relevant part of the code > > > > //Configure interrupts > > INTCON2bits.TMR0IP = 1; //set timer0 interrupt at high priority > > IPR1bits.TMR1IP = 1; //set timer1 interrupt at high priority > > PIE1bits.SSPIE = 1; //enable MSSP interrupts > > IPR1bits.SSPIP = 0; //set MSSP interrupt as low priority > > INTCONbits.GIE = 1; //global interrupts enable > > > > can anyone help me out here? You need to set the IPEN bit in the RCON REGISTER to enable interrupt priority levels.

Oh, I should mention the chip is PIC18F458 and the high vector is 0x08, and the low vector is 0x18 --- In , "Vecheslav Silagadze" <uwobjectivist@h...> wrote: > > I've setup two interrupt routines. One for a timer and one for I2C. > It seems both are sent to the high priority vector even though I > setup the I2C as low priority. > > here's the relevant part of the code > > //Configure interrupts > INTCON2bits.TMR0IP = 1; //set timer0 interrupt at high priority > IPR1bits.TMR1IP = 1; //set timer1 interrupt at high priority > PIE1bits.SSPIE = 1; //enable MSSP interrupts > IPR1bits.SSPIP = 0; //set MSSP interrupt as low priority > INTCONbits.GIE = 1; //global interrupts enable > > can anyone help me out here?

I've setup two interrupt routines. One for a timer and one for I2C. It seems both are sent to the high priority vector even though I setup the I2C as low priority. here's the relevant part of the code //Configure interrupts INTCON2bits.TMR0IP = 1; //set timer0 interrupt at high priority IPR1bits.TMR1IP = 1; //set timer1 interrupt at high priority PIE1bits.SSPIE = 1; //enable MSSP interrupts IPR1bits.SSPIP = 0; //set MSSP interrupt as low priority INTCONbits.GIE = 1; //global interrupts enable can anyone help me out here?

Re: low VS high priority interrupt routines