Problem - Embedded System Design

[jokunen]

Homework Statement

Your embedded system has an 8-bit microprocessor, which has a 16-bit address bus. In addition, you have a 32-Kbyte FLASH chip, and a 8 KByte RAM chip. You want to locate the FLASH chip right in the beginning of the address space and the RAM at the end of the address space. All the memory chips have a single /CS selection line, which is controlled by a fast 32 x 8 OTP-ROM chip.

What are you going to program into the contents of the OTP-ROM, and how do you connect it to the microprocessor and the memory chips?

I got only 1.5p out of 6 points by using a solution similar to the picture I attached. The prof told me the following:

"you got one point for the correct OTP-ROM circuit outputs connection and ½ points for connecting address lines a15 and a14 to OTP-ROM circuit. Other than that, the connection was wrong, and the contents of memory were not given/solved at all."

Please help me in this problem. Any advices are appreciated.

From where should I start? And what I should program into the opt-rom? A 32x8 matrix full of ones and zeros?

Homework Equations

block diagram of the opt-rom (see the below.):

http://oi42.tinypic.com/2m8605v.jpg

The Attempt at a Solution

my (wrong) solution:

http://oi44.tinypic.com/13zxwdc.jpg

 

[berkeman]

I'd recommend starting by drawing out the memory map for the external memory circuit. Show the address range for each memory part, and show what that means for what has to go into the decode ROM.