BusTools/1553-API does not support hardware interrupts for the PCCCARD-1553, because the PCMCIA driver has no interrupt support. However, you can use the PCCARD-1553 with software interrupts that run off a 10 millisecond timer. These interrupts work the same as hardware interrupts except that instead of getting an interrupt from the PCCARD-1553 board, you get the interrupt from the timer. The interrupt-software processes all messages in the interrupt queue at that time. You can use hardware interrupts with the PCCARD-1553 if you provide a PCMCIA driver that support interrupts. See the BusTools_API_InitExternal () in the "BusTools/1553-API Software Reference Manual".