SCOOP_ISR
bus_space_write_2(iot, ioh, SCOOP_ISR, 0x0000);
bus_space_write_2(iot, scooph, SCOOP_ISR, 0x0000);
bus_space_write_2(iot, ioh, SCOOP_ISR, 0x0000);
isr = ioreg16_read(baseaddr + SCOOP_ISR);