ChipWise Tutor Workbook
02/11/13
1
NAME
LOGIN
COURSE
1) Aims
The aim of ChipWise Tutor is to expose you to the design and simulation of CMOS VLSI circuits at
both circuit and logic level. This is achieved through exercises, which cover circuit level design and its
effect on perform
ance, stick layout, simulation at transistor level and switch level and hierarchical
design. The subject is presented in seven parts:
A Tutorial Guide to ChipWise
Transistor Sizing of a Logic Inverter
Design and Simulation of Simple Logic Gates
Design
of a 4

bit Shift Register
Design of a Parallel Load Shift Register
Design of a Universal Logic Module using a 4:1 Multiplexer
Design of a Parity Generator
2) The Workbook
This workbook is for you to log results as you work through the ChipWise Tutor cou
rse material. For each
frame in this workbook, there is a corresponding workbook icon in the Web based courseware. As you
work through ChipWise Tutor, whenever you see a workbook icon, you know you must complete the
appropriate frame in the workbook. It sh
ould be handed in to your demonstrator when you have finished.
3) Screendumps
Throughout this workbook, you will be asked to paste in the appropriate screendump from
ChipWise. To do this, follow these steps:
Select the
Monochrome
option from the required
window's men

bar.
Press
<Alt

Print Scrn>
to copy the current window into the clipboard buffer.
Place the cursor in the appropriate frame in the workbook, and use the
Paste
command from the
MS Word
Edit
menu to copy the screendump into the workbook.
Select
the pasted image and scale it to fit the frame.
4) Module 1: A Tutorial Guide to ChipWise
For the first module
, A Tutorial Guide to ChipWise
, there is no need to take notes … just work through
the tutorial to get a feel for using the ChipWise design system
and the Web based courseware which guides
you in using the tools.
Week
15,
2000
/01
ChipWise Tutor Workbook
02/11/13
2
Module 2: Transistor Sizing of a Logic Inverter
2.2 DC Analysis of Logic Inverter
P

type width = N

type width
Vinv = ………………………………………….
P

type width = 2.5 x N

type width
Vinv = …………………
……………………….
Why is this value closer to Vdd/2 than before?
2.3 Transient Analysis of a Logic Inverter
P

type width = 2.5 x N

type width
Rise Time = ………………………………
Fall Time = …………………………
……
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
3
P

type width = N

type width
Rise Time = ………………………………
=
Fall Time = ………………………………
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
4
Module 3: Design and Simulation of Simple Logic Gates
3.4 Device Sizing and Simulation of the NAND gat
e
Minimum Sized Transistors
–
Waveforms A
Rise Time = ………………………………
Fall Time = ……………………………….
The 2

input NAND gate
Minimum Sized Transistors
–
Waveforms B
Rise Time = ………………………………
Fall Time = ……………………………….
Explain the above results
Width
of N

type transistors doubled
Rise Time = ………………………………
Fall Time = ………………………………
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
5
3.5 Design and Simulation of a 2

Input NOR Gate
Minimum Sized Devices
Rise Time = ………………………………
Fall Time = ………………………………
Sketch the circuit diagram of the 2

input NOR gate in
this frame
Explain Your Results
What should the widths of the devices be if we wish to have rise and fall
times at least as fast as the
sized logic inverter? Explain Your Results.
Size of N

type devices (in microns) ………… Size of P

type devices (in microns) …………
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
6
Module 4: Design of a 4

bit Shift Register
4.2 Circuit Level Simulation of sreg
Paste the sc
reendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
7
4.6 Logic Level Simulation of sreg
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
8
Module 5: Design of a Parallel Load Shift Register
5.1 Derivation of Circuit Diagram from a Stick Diagra
m
Transistor

level circuit diagram
Circuit Level Simulation of Shift Register Cell
Sketch the transistor

level diagram of the shift register circuit in this frame
Paste the screendump from the output of SVIEW into this frame
Sketch the logic level d
iagram of the shift register circuit in this frame
ChipWise Tutor Workbook
02/11/13
9
5.2 Design of one

bit Shift Register Cell with Parallel Load
Symbolic Level Design of Modified Shift Register Cell
Explain how the shift register cell operates
Paste the screendump of the modified s
hift register cell into this frame
ChipWise Tutor Workbook
02/11/13
10
Circuit Simulation of modified Shift Register Cell
Circuit Diagram of Modified Shift Register Cell
Paste the screendump from the output of SVIEW into this frame
Sketch the circuit diagram of the modified shift regis
ter circuit in this frame
ChipWise Tutor Workbook
02/11/13
11
5.3 Design of a 4

bit Shift Register with Parallel Load
Logic Level Simulation of
preg4
–
Serial Input Mode
Describe briefly the operation of your modified cell with reference to the simulation results
Paste the screendump f
rom the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
12
Logic Level Simulation of
preg4
–
Parallel Load Mode
Mask Level Design of preg4
Paste the screendump from the output of SVIEW into this frame
Paste the screendump of preg4 into this frame
ChipWise Tutor Workbook
02/11/13
13
Logic Level Simula
tion of
preg4
with given waveforms
The following waveforms will cause the register to parallel load ‘0101’ and then to serially shift it out of
q3 whilst loading new data through d0:
Paste the screendump from the output of SVIEW for the above input wa
veforms, into this frame
ChipWise Tutor Workbook
02/11/13
14
Module 6: Design of a 4:1 Multiplexer
6.1 Design of a 4:1 Multiplexer
Circuit Level Simulation of 4:1 Multiplexer cell
Maximum voltage swing = ………………………………………….
Minimum voltage swing = …………………………………………..
Explain the effect
ChipWise Tutor Workbook
02/11/13
15
Improving the Output Swing
This circuit, added to the output of the Multiplexer,
improves the output swing of your Multiplexer
Explain how transistor Tp and the inverter
impr
ove the output voltage swing of the circuit
An interesting experiment that you can carry out is to monitor the current drawn by the inverter when
‘out’ is high and compare that to the current drawn under the same circumstances but with Tp removed.
Ex
plain the difference.
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
16
6.2 Use of a 4 to 1 Multiplexer as a programmable Logic Element
Paste the screendump of your stick diagram into this frame
ChipWise Tutor Workbook
02/11/13
17
The circuit on the left can be used to generate
various logic functions of a and b under the contro
l
of [c3 … c0]. From the result of the circuit level
simulation of this circuit with 0V applied to c3, 5V
applied to c2, c1 and c0, identify the logic function
produced.
Identify the logic levels which need to be
applied to [c3 … c0] to achieve the
logic
functions shown.
function
c3
c2
c1
c0
1
a + b
2
a EXOR b
3
a AND b
4
b
5
1
Sketch the floorplan of a structure , based on the programmable Logic Element, which can be used in
an ALU to produce various logic funct
ions of two 16

bit words, showing the flow of Data and Control.
ChipWise Tutor Workbook
02/11/13
18
Module 7: Parity Generator Cell
7.2 A VLSI Implementation of a Parity Generator Cell
The circuit shown below
can be used as a Parity
Generator Cell:
Circuit Level Simulation of the Parity Cell
Paste the screendump of your stick diagram of the Parity Cell
into this frame
Paste the screendump from the output of SVIEW for the circuit level simulation of the Parity Cell, into this frame
ChipWise Tutor Workbook
02/11/13
19
Circuit Level Simulation of Parity Cell with lev
el

restore stage
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
20
7.3 An 8

bit Parity Generator
Circuit Level Simulation of an 8

bit Parity Generator
The circuit level simu
lation of the one

bit parity cell showed an output logic 1 voltage of approximately
4Volts. What is the output voltage swing of the 8

bit parity generator?
Explain the result
Paste the screendump from the output of SVIEW into this frame
ChipWise Tutor Workbook
02/11/13
21
Logic Level Simulation of an 8

bit Parity Generator
Comment on any differences between these results and those obtained from circuit level simulation with
SPICE.
Paste the screendu
mp from the output of SVIEW into this frame
Comments 0
Log in to post a comment