CSE370 Assignment 7

Distributed: Feb. 18, 1998
Due: Feb. 27, 1998

Reading:

Katz: Chapter 6: pp. 289, 299-301, 305-306, 309-312 (Pay attention only to what is said about positive edge-triggered flip-flops!)
Katz: Chapter 7: pp. 329-344,350 (Ignore everything uses anything besides positive edge-triggered flip-flops!)

Exercises:

1. Using just the basic D flip-flop and combinational logic, design an 8-bit register with load (clock enable), clear and output-enable (tristate) control signals. (Use abbreviations where appropriate.)

2. Write an ABEL program to implement the register of problem 1. Compile this into a block symbol, put it into a schematic and test it. Turn in everything!

3. Using the 8-bit register you designed in problem 1, design a dual-ported memory with four 8-bit words. This memory has two ports, one for reading and one for writing. Each port has a set of data lines and a set of address lines. In addition, the write port has a WRITE control line that determines whether or not the memory will load data on the next clock cycle.

4. Write an ABEL program to implement the memory of problem 3, using the register designed in problem 2. Compile this into a block symbol, put it into a schematic and test it. Turn in everything!

5. Now design a single-ported memory with four 8-bit words. This memory has a single port with data lines, address lines and a R/W signal which indicates whether the memory should be reading or writing. When R/W is 1, the memory reads the data at the given address onto the data lines. When R/W is 0, the memory writes the data that the user puts on the data lines into the given address. Note that when writing, the memory must tristate the data outputs in order not to fight with the data being written.

6. Design an 8-bit shift register with 3-bits of control (S2,S1,S0) which define the operation of the shift register as follows:

   S=0: Hold (NOP)
   S=1: Load input
   S=2: Clear
   S=3: Complement contents
   S=4: Shift right 1
   S=5: Rotate right 1
   S=6: Shift left 1
   S=7: Rotate left 1
   

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