# ECE - Study Guide: Physical Memory addresses how many bytes?

Attempting to do this study guide, but i'm not finding too much help online. Any help is welcome, and a explanation would be nice, as my text book does not describe how to answer a problem given the information.

The figure: ][2]

Questions:

1. How much physical memory can the microprocessor address?

2. How many words does the memory IC contain?

3. What is the address range for the memory? That is, if one wanted to access this memory with a program, what range of addresses would "talk" to this memory chip?

• You should be able to quickly find answers to this type of question on the web. For example, I searched for address range of 24 bits and found Wikipedia "24 bit". You have been fortunate that anyone answered, we usually expect more evidence of effort. – gbulmer Dec 18 '15 at 9:38
• @gbulmer well that's not quite what I was looking for nor is that the correct cpu/memory design – StingRay21 Dec 18 '15 at 14:36
• I think the wikipedia link answers part 1 of your question, "How much physical memory can the microprocessor address?". Similarly part 2 of your question is answered by the Wikipedia 18-bit address range of the memory. If that is not the case, then IMHO you need to update your question to explain why, because the answer you have accepted is that same information. – gbulmer Dec 18 '15 at 14:41
• @gbulmer ahh I see now. I didn't see the correlation when I very first searched and looked through those wiki pages. Thank you very much :) – StingRay21 Dec 18 '15 at 15:09

3. What value do the upper bits of the address bus (those connected to the address decode module) have to be in order for the select_memory signal to be asserted? (make a lookup table for the circuit of the decode described). Now you know the starting address (upper bits select the memory, lower bits are 0), and the ending address (upper bits still selecting the memory, lower bits all 1). So convert both those binary numbers to decimal and you have your range of addresses.