https://www.youtube.com/watch?v=rZeh4uwSvvs&t=14s

Assignment 11

Design a microprocessor system that has the following specifications:

1. 16 Kbytes RAM chips, to hold the sampled data and processing results.
2. The available RAM units are of 2 Kbytes each.
3. 30 Kbytes ROM to hold the main program.
4. The available ROM units are of 4 interrupts done to improve processing efficiency Kbytes each.
   • Illustrate the ROM & RAM design issues
   • Illustrate the worksheet for RAM(s) & ROM(s)

Solution

RAM Design Issue:

1. Analyze the program RAM Requirements:
   • We need to add the system 8 RAMs, each of a 2 KB capacity.
   • $2K = 2*1024 = 2048 ( 0 → 2047)$ , Hex = 7FF
   • $2K = 2^1 *2^{10} =2^{11}$ → we will need 11 address lines to address each chip. → $A_1-A_{11}$
2. Determine the requirements of select lines:
   • Since we have 8 RAMs chips $8=2^3$ we will use 3 select lines. $A_{12} , A_{13} , A_{14}$
   • $A_{15} = 0$ for RAM
3. Notice that the lowest and highest address lines for each chip don’t change ⇒ we wrote the Address lines don’t care <x>
4. Last memory address occupied by RAM= 03FFF

ROM Design Issue:

1. Analyze the program ROM Requirements:
   • We need 30 Kbytes capacity for memory storage.
   • We can use 8 ROMs each of 4 KB to have enough memory (32 KB) to hold the program.
   • $4K = 4*1024 = 4096 ( 0 → 4095)$ , Hex = FFF
   • $4K = 2^2 *2^{10} =2^{12}$ → we will need 12 address lines to address each chip. → $A_1-A_{12}$