Hi,
Im working on a project involving the AT91rm9200. Im trying to generate interrupts through the System Timer`s Periodic Interval Timer. Its not working the way i want it to. Im getting periodic interrupts all right, but im not able shut it off properly. I keep getting timer interrupts continuously..the code of my C interrupt handler is below: (as may be evident, im using atmel`s pre-canned asm routines in the file irq.mac for backstage interrupt handling, but the C routines are mine )
void timer_c_irq_handler() { //Dummy variable used for clearing ST_SR volatile int status;
AT91PS_ST pST =3D AT91C_BASE_ST;
//read ST_SR status =3D pST->ST_SR;
//clear the interrupt for re-use AT91F_AIC_ClearIt( AT91C_BASE_AIC,AT91C_ID_SYS );
//Disable interrupts by the timer //AT91F_ST_DisableIt( AT91C_BASE_ST, AT91C_ST_PITS );
AT91F_DBGU_Printk("\n\rSystem Timer interrupt..\n\r");
}
As u can see, im try =B7 PITS: Period Interval Timer Status
0 =3D The period interval timer has not reached 0 since the last read of the Status Register.
1 =3D The period interval timer has reached 0 since the last read of the Status Register.
So shouldnt PITS go to 0 if i read it again in the irq handler above, and stop bothering the AIC? Everything works fine if i uncomment the "DisableIt" function call, but just want to be clear about where im going wrong.
Thanx in anticipation
Mayank