UCR EE/CS 120B   Digital Systems   Winter 2000 Professor Frank Vahid

Homework 2  Due: Thursday, 2/17/00, BEFORE lecture.  You can turn it
in before lecture begins at 11:10, or put it under the door of
A207 before 11:00.  Remember to turn in a neat homework. 
Don't forget the required "This is my own original work" statement 
at the top. SHOW YOUR WORK for every problem.

1. (a) Draw the external interface of a 128x2 RAM, with ALL inputs
       and outputs clearly labeled. Don't forget chip chip select. Also,
       don't group your address lines, but rather draw them separately.
       Do NOT draw the internal design of the RAM.
   (b) Using some number of the RAMs created in (a), design a
       512 x 4 RAM. You may group address lines, but you must very
       clearly which bits are grouped.  Again, don't forget a chip
       select input on you 512x4 RAM.


2. Write the complete control word for the following (independent) operations 
   on the datapath of Figure 7.26(a). Use the control word format of Figure 
   7.26(d), and NOT the shorthand format of 7.27(c). Don't make any 
   assumptions as to the prior contents of the registers.  If a control 
   word can't be done in one cycle, break it into two or more control words.
   (a) R0 = Inport
   (b) R1 = R0 + R1
   (c) R2 = 1
   (d) R7 = 2 * (R6 - 1)
   (e) R5 = Inport + 1


3. Gajski problem 8.7 (Converting sequential code to an ASM chart).

4. Gajski problem 8.10 (Register sharing using left-edge algorithm).

5. Gajski problem 8.11(b) (Register sharing using graph partitioning).