A fully?populated NuBus has 16 possible interrupting devices. Device numbers 12, 1, 7, and 9 all interrupt at the same time. Show the sequence of operations that take place on the bus as each device requests and then gives up or retains the bus during the distributed arbitration, until device 12 wins.

What will be an ideal response?

NuBus uses active low signals; that is device 12 which is 1100 puts the signal 0011 on the bus (low, low, high, high). Remember that BuBus uses wired OR open?collector bus drivers which means that if a group of devices drive a bus line with different logic values, electrical low level wins







Only one device is left requesting the bus. Device 12 wins.