В datasheet на SAM7S сказано, что [24.6.2] PMC has no effect on the AIC behavior. Тогда зачем в lib_AT91SAM7S64.h ... ... тогда зачем в lib_AT91SAM7S64.h например вот это:
//*---------------------------------------------------------------------------- //* \fn AT91F_AIC_CfgPMC //* \brief Enable Peripheral clock in PMC for AIC //*---------------------------------------------------------------------------- __inline void AT91F_AIC_CfgPMC (void) { AT91F_PMC_EnablePeriphClock( AT91C_BASE_PMC, // PIO controller base address ((unsigned int) 1 << AT91C_ID_FIQ) | ((unsigned int) 1 << AT91C_ID_IRQ0) | ((unsigned int) 1 << AT91C_ID_IRQ1)); }