static void ISR_Tc2(void)
{
    AT91C_BASE_TC2->TC_SR;
}

void clock_init(void)
{
    unsigned int div, tcclks;
    AT91C_BASE_PMC->PMC_PCER = 1 << AT91C_ID_TC2;
    TC_FindMckDivisor(CLOCK_CONF_SECOND, BOARD_MCK, &div, &tcclks);
    TC_Configure(AT91C_BASE_TC2, tcclks | AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO);
    AT91C_BASE_TC2->TC_RC = BOARD_MCK / (CLOCK_CONF_SECOND * div);
    AIC_DisableIT(AT91C_ID_TC2);
    AIC_ConfigureIT(AT91C_ID_TC2, 0, ISR_Tc2);
    AT91C_BASE_TC2->TC_IER = AT91C_TC_CPCS;
    AIC_EnableIT(AT91C_ID_TC2);
    TC_Start(AT91C_BASE_TC2);
}