RAM/ROM Implementation
Pre-lab: 10 pts
Provide circuit diagrams for each step. Develop tables of the
values that you need to put into RAM and ROM in steps 1, 2, and
3. Use the EPROM Programmer to verify that your EPROM is in the
erased state. Prepare a file on a 5.25" DSDD diskette that
contains the values of the table for step #3 that will be programmed
into your EPROM.
Your circuit diagrams and tables will be collected at the start
of the lab. Make a copy of them for your own use during lab.
In-lab: 15 pts
- RAM Implementation. Use a 7489 16*4 bit RAM to implement
the code converter from the previous lab. Let DCBA be the address
inputs and ZYXW the data outputs. Since the outputs of the 7489
are inverted, run the signals through inverters (7404) and then
to the logic indicators. Show your working circuit to the instructor
and have him initial this step.
- RAM Implementation Expansion. Add a second 7489 to
the circuit above to implement the code converter and its inverse.
Let a control signal of 0 specify the conversion and a 1 its inverse
(e.g., for excess-6 code: C=0, 0011-> 1001; C=1, 1000->
0010). The outputs of the 7489 are open-collector, so they can
be wired-ORed together before they are input to the inverters.
Demonstrate this to the instructor and have him initial this step.
- EPROM Implementation. NOTE: The 2716 is a static
sensitive device--take appropriate antistatic precautions.
Use a 2716 2K*8 EPROM and 74194 shift register to implement the
sequential circuit from the previous lab.
- Show your working circuit to the instructor and have him
initial this step.
- Compare the cost (with respect to chip count and wiring
complexity) of constructing this sequential circuit using
an EPROM to discrete logic components done in the last experiment.
Beginning of Lab
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