void AT91F_TC_Open(AT91PS_TC TC_pt, unsigned int Mode, unsigned int TimerId)
//* Begin
{
unsigned int dummy;

//* First, enable the clock of the TIMER
AT91F_PMC_EnablePeriphClock ( AT91C_BASE_PMC, 1<< TimerId ) ;

//* Disable the clock and the interrupts
TC_pt->TC_CCR = AT91C_TC_CLKDIS ;
TC_pt->TC_IDR = 0xFFFFFFFF ;

//* Clear status bit
dummy = TC_pt->TC_SR;
//* Suppress warning variable "dummy" was set but never used
dummy = dummy;
//* Set the Mode of the Timer Counter
TC_pt->TC_CMR = Mode ;

//* Enable the clock
TC_pt->TC_CCR = AT91C_TC_CLKEN ;
//* End
}

__ramfunc void timer0_c_irq_handler(void)
{
AT91PS_TC TC_pt = AT91C_BASE_TC0;
unsigned int dummy;
//* Acknowledge interrupt status
dummy = TC_pt->TC_SR;
//* Suppress warning variable "dummy" was set but never used
dummy = dummy;

}

...
AT91F_TC_Open(AT91C_BASE_TC0, TC_CLKS_MCK1024, AT91C_ID_TC0);

//* Open Timer 0 interrupt
AT91F_AIC_ConfigureIt(AT91C_BASE_AIC, AT91C_ID_TC0, 0x4, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, timer0_c_irq_handler);
AT91C_BASE_TC0->TC_IER = AT91C_TC_COVFS;
AT91F_AIC_ClearIt(AT91C_BASE_AIC, AT91C_ID_TC0);
AT91F_AIC_EnableIt(AT91C_BASE_AIC, AT91C_ID_TC0);

AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
...