Assume that one 16-bit and two 8-bit microprocessors are to be interfaced to a system bus. The following details are given:
1. All microprocessors have the hardware features necessary for any type of data transfer: programmed I/O, interrupt-driven I/O, and DMA.
2. All microprocessors have a 16-bit address bus.
3. Two memory boards, each of 64 KBytes capacity, are interfaced with the bus. The designer wishes to use a shared memory that is as large as possible.
4. The system bus supports a maximum of four interrupt lines and one DMA line. Make any other assumptions necessary, and
a. Give the system bus specifications in terms of number and types of lines.
b. Describe a possible protocol for communicating on the bus (i.e., read-write, interrupt, and DMA sequences).
c. Explain how the aforementioned devices are interfaced to the system bus.