(Solved): 1. A computer has a CPU with 20-bit address bus and 16-bit data bus. We would like to add RAM to th ...

1. A computer has a CPU with 20-bit address bus and 16-bit data bus. We would like to add RAM to this system in the address range $60000\mathrm{H}?7\mathrm{FFFFH}$ with full decoding (all addresses should have corresponding physical memory, 16 bits per cell; no two addresses should map to the same physical memory location). The following chips are available: We would like to compare the cost of the memory addition using $32\mathrm{Kx}8\mathrm{RAM}$ chips versus using 16Kx16 RAM chips. In order to make a decision, however, we need to design both options and compare their costs. a) Design the memory addition using $32\mathrm{Kx}8\mathrm{RAM}$ chips, draw the circuit diagram and calculate the minimum cost. b) Design the memory addition using $16\mathrm{Kx}16$ RAM chips, draw the circuit diagram and calculate the minimum cost. 74LS138 3-to-8 decoder has two active low (assert low) and one active high (assert high) enable inputs. Assume it has active high outputs. 74LS155 2-to-4 decoder has one active low and one active high enable inputs. Assume it has active high outputs. Show chip select, address, and data connections to memory chips. Indicate the inputs and outputs of all chips clearly. You may ignore the WE and OE connections.