//------------------------------------------------------------------------------
/// Interrupt service routine for the PIT. Debounces the wake-up pin input.
//------------------------------------------------------------------------------
static void ISR_Pit(void)
{
static unsigned long debounceCounter = DEBOUNCE_TIME;
unsigned long pisr = 0;
// Read the PISR
pisr = PIT_GetStatus() & AT91C_PITC_PITS;
if (pisr != 0) {
// Read the PIVR. It acknowledges the IT
PIT_GetPIVR();
}
// Button released
if (PIO_Get(&pinWakeUp)) {
debounceCounter = DEBOUNCE_TIME;
}
// Button still pressed
else {
debounceCounter--;
}
// End of debounce time
if (debounceCounter == 0) {
debounceCounter = DEBOUNCE_TIME;
PIT_DisableIT();
AT91C_BASE_PITC->PITC_PIMR &= ~AT91C_PITC_PITEN;
COMPOSITEDDriver_RemoteWakeUp();
}
}
void PitInit(unsigned int msperiod)
{
PIT_DisableIT();
// Initialize the PIT to the desired frequency
PIT_Init(0, 0);
// PIT timer runs at MCK/16
// calculates the PIT Value accurate to a Millisecond interrupt
// msperiod can not be larget than 349 because PIV is at a 20bit limit
if(msperiod > 349) msperiod = 349;
PIT_SetPIV((MCK/(16*1000))*msperiod);
// Configure interrupt on PIT
AIC_DisableIT(AT91C_ID_SYS);
AIC_ConfigureIT(AT91C_ID_SYS, AT91C_AIC_PRIOR_LOWEST, ISR_Pit);
AIC_EnableIT(AT91C_ID_SYS);
PIT_EnableIT();
// Enable the pit
PIT_Enable();
}
