CS 2204 Spring 2007
Experiment 4
Lab 8

Experiment 4 Lab 8 Outline
 Presentation

Digital product development overview
 Using Digital Product Development

The high-level design of the term project
 The operation diagram, major operations and blocks
• Ppm blocks 2 and 3

Digital systems
 Individual work

Experiment 4
 Develop a BCD up counter (using class notes)

No new handout
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 2

Presentation
 Developing a Digital Product

CS2204 sets out to develop a prototype
 A prototype chip
 A prototype PCB

If everything goes well and the product is not
obsolete, it is mass produced
 Mass produce the prototype chip
• Whoever wants to use the chip must develop a new
PCB
 Mass produce the prototype PCB
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 3

Developing a digital product
 A new chip

Which gates/FFs and how many is determined by
 The application (major operations)
 Available components of the technology chosen
 Besides speed, cost, power, etc. : product goals
 A new PCB

Which chips and how many is determined by
 The application (major operations)
 Available chips of the technology chosen
 Besides speed, cost, power, etc. : product goals
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 4

Developing a new chip
1) Development Cycle on Computers
Major error : Redesign
Design
TEST
MODIFY
Major error : Redesign or terminate the project due to TTM
2) Development Cycle with FPGA chips
Mount
Test
Modify
Major error : Redesign or terminate the project due to TTM
3) Development Cycle on prototype chip
Fabricate
Test
CS 2204 Spring 2007
TEST : applying input combinations,
test vectors, and simulating
During testing you will see modifying
hardware to minimize it is possible. Do
that after you correct logic and timing
errors. Then, test again to see if your
minimization has logic/timing errors
Mount : FPGAs are mounted on
bread/boards, wired and programmed
Test : apply test vectors to FPGAs
Modify : either FPGA mounting/wiring
is changed or a simple design change is
made on computers, simulated, then
FPGAs are programmed and tested
Fabricate chip by sending a GDSII file
to a fabrication facility : tape out
Apply test vectors to the chip
Experiment 4 Lab 8
Page 5

Development Cycle on Computers

DESIGN
1) Input/Output Relationship
a) A simple circuit
Obtain the truth table of the combinational circuit with
less than 5 inputs then move on to Implementation (2)
Obtain the state diagram of the sequential circuit with
less than 5 FFs then move on to Implementation (2)
b) A complex circuit

Obtain the operation table or the operation diagram
►Try to implement it

If it cannot be implemented immediately in (2)
► Partition it


2) Implementation Try to use registers, counters,
TEST
MODIFY
shift registers even if it is a
simple sequential circuit
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 6

Development Cycle on Computers
For the current (sub)block we can get a truth table or a state diagram ?
Step I (a)
N
Y
Obtain an operation table or an operation diagram
Step I (b)
Current (sub)block is implementable ?
Step II
Y
Implement the current (sub)block
Step II
N
Partition it into (sub)blocks
Step I (b)
Works and satisfies design goals ?
TEST
Y
Any other (sub)block
to implement ?
Y
N
A simple design change
MODIFY
N
Design complete
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 7

Designing a Complex Block
 Partition it into pieces based on major operations

Besides the design goals and the technology
 One block for each major operation

These major operations are often
 Additions, MUXings, comparisons, decodings, encodings,
DeMuxing, registering, counting, etc.

These operations are already implemented by available
components/chips :
 ADDers, Multiplexers, Comparators, Decoders, Encoders,
DeMuxes, Registers, Counters, shift registers, etc.

This happens frequently for real-life applications
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 8

An Unusual Major Operation (an unusual block)
 Trying to implement a block

If it has < 11 inputs implement it by using programmable
components
 Memory components
• ROMs, RAMs

Otherwise (complex or too many inputs)
 Break it up or
 Repartition one level up, or
• Two levels up, or,…
• All the way up (redesign !?)
 Eventually, the resulting operations will be additions,
comparisons, multiplexing, decoding, etc.
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 9
Designing a New Chip


DESIGN
1) Input/Output relationship
a)
A simple block
Combinational circuit
A circuit with less than 5 inputs
Obtain a truth table
Obtain circuit expressions
Sequential circuit
A circuit with less than 5 FFs
 Obtain a state diagram
 Obtain circuit expressions
Move on to the Implementation step, (2)
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 10

Designing a New Chip

DESIGN
1) Input/Output relationship
b) A complex block
Obtain the operation table/diagram
Try to implement it (Step 2)
If impossible, partition the block based on
 Application (major operations) : a subblock
for each major operation
 Design goals : speed, cost, power, size,…
► Speed, cost, power,… depend on the technology
 Available components : components of the
technology
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 11
Designing a New Chip


DESIGN
2) Implement each circuit
i.
CS2204
One or more Xilinx Design Blocks, XDBs or Xilinx nonprogrammable macros (not gates and FFs) implement
the circuit ? A few gates and FFs here and there ?
• If yes, draw the schematic and move to the TEST
step
ii. One or more Programmable Xilinx macros implement
the circuit ? A few gates and FFs here and there ?
 If yes, draw the schematic, program the macros
and move to the TEST step
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 12
Designing a New Chip


DESIGN
2) Implement each circuit
CS2204
iii. Simple enough to be designed quickly using Switching
Theory (less than 5 inputs or less than 5 FFs) so a few
gates and/or FFs needed ?
• If yes, draw the schematic and move to the TEST
step
iv. The circuit can be licensed ?
• If yes, borrow it, place it and move to the TEST
step
v. If no to all the above questions, go back to step 1(b) to
partition it further or repartition one level up, two
levels up,,, or, all the way up
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 13
Designing a New Chip


TEST

Test (sub)blocks separately


Functional and timing simulations by applying test
vectors
• Pick the right test vectors and the right order of
them
• Note down these combinations and output values to
use them during later testing steps
Combine (sub)blocks one at a time
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 14

Designing a New Chip
 MODIFY
A simple change
 Minimize the circuit after you think your circuit
does not have logic and timing errors

 After the minimization, test the circuit to make sure the
minimization does not introduce logic and timing errors
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 15
Development Cycle
with FPGA chips
Development Cycle on Computers

Xilinx Project Development Steps
 Develop the schematic

DESIGN the schematic
 Design blocks, (sub)blocks
• Place the components and wires



Do integrity TESTs
TEST the schematic via functional simulations
MODIFY the schematic to correct an error
What are these
components ?
 Do a Xilinx IMPLEMENTATION

It maps the components to the CLBs of the chip
 Do timing simulations to TEST the schematic

It generates the bit file
 Download the bit file to the FPGA and test the
design on the board

It programs the chip
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 16

CS2204 components
 Available components for a new chip
Use these Generic components
Lectures, homework, exams
as much
as possible
Gates
Flip-flops Popular digital circuits
AND
D
OR
JK
NOT
T
NAND
SR
NOR
…
…
To save time,
space, power.
weight,…
ADDer
Comparator
Multiplexer
DeMux
Decoder
Encoder
ALU
Counter
Register
…
Xilinx components
Labs
Gates
AND
OR
NOT
NAND
NOR
…
CS 2204 Spring 2007
Flip-flops
D
JK
Popular digital circuits
ADDer
Comparator
Multiplexer
DeMux
Decoder
Encoder
ALU
Counter
Register
…
Experiment 4 Lab 8
Page 17

Implementing a Combinational Circuit on a New Chip
 By using generic components that are AND, OR, NOT,…

a
The 2-to-1 MUX
Which components ?
1 inverter
2 2-input AND gates
1 2-input OR gate
NOT
b
AND
Total : 4 gates used
OR
c
a
AND
y(a, b, c) = a.b + a.c
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 18

Implementing a Combinational Circuit on a New Chip
 By using generic components that are AND, OR, NOT,…
a
ab
Which components ?
b
a
ad
d
z
d
a
ac
c
ab + ad + ac + c d + b c
c
c
2 inverters
5 2-input AND gates
1 5-input OR gate
Total : 8 gates used
cd
d
b
bc
c
2-bit Unsigned Binary Comparator
From Handout 5
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 19
Implementing a Sequential Circuit on a New Chip

 By using generic components that are D, J-K, AND, OR, NOT,…
The sequence detector from Handout 10

y1
x
J
y0
y1
Q
y2
Q
C
K
clock
y2
x
y0
J
x
y0
y0
y2
x
y0
Q
C
K
x
Q
y1
clock
y2
Least significant FF
x
y2
J
y0
x
y1
y2
K
C
Which components ?
y0
1 inverter
4 2-input AND gates
6 3-input AND gates
1 4-input AND gate
4 2-input OR gates
2 3-input OR gates
3 J-K FFs
most significant FF
Total : 21 components used
x
y1
x
Q
y0
y1
clock
y0
y1
CS 2204 Spring 2007
z
y2
Q
x
y2
y2
y2
x
Experiment 4 Lab 8
Page 20

CS2204 Components
Lab design
 Available components for a new chip
Generic components
Lectures, homework, exams
Gates
AND
OR
NOT
NAND
NOR…
Flip-flops
D
JK
T
SR
Popular digital circuits
ADDer
Comparator
Multiplexer
DeMux
Decoder
Encoder
ALU
Counter
Register…
Xilinx components
Labs
Gates
AND
OR
NOT
NAND
NOR…
Flip-flops Popular digital circuits
D
T
JK
Try not to use
these components
CS 2204 Spring 2007
Use Xilinx macros
as much as possible
ADDer
Comparator
Multiplexer
DeMux
Decoder
Encoder
ALU
Counter
Register…
Experiment 4 Lab 8
Page 21

Implementing a Combinational Circuit on a New Chip
 By using Xilinx components that are AND, OR, NOT,…

a
The 2-to-1 MUX
Which components ?
1 inverter
2 2-input AND gates
1 2-input OR gate
NOT
b
AND
Total : 4 gates used
OR
c
a
AND
y(a, b, c) = a.b + a.c
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 22

Implementing a Combinational Circuit on a New
Chip
 By using Xilinx components that are AND, OR, NOT,…

The 2-to-1 MUX
Xilinx already has 2-to-1 MUXes
Use them
Do not design your own 2-to-1 MUX
a
NOT
b
AND
OR
c
a
AND
CS 2204 Spring 2007
y(a, b, c) = a.b + a.c
Experiment 4 Lab 8
Page 23

Implementing a Combinational Circuit on a New Chip
 The 2-to-1 MUX

Xilinx already has 2-to-1 MUX macros
 M2_1
Which components ?
1 Xilinx M2_1 MUX
Total : 1 component used
a
NOT
b
AND
OR
c
a
AND
CS 2204 Spring 2007
y(a, b, c) = a.b + a.c
Experiment 4 Lab 8
Page 24

Implementing a Combinational Circuit on a New Chip
 By using Xilinx components that are AND, OR, NOT,…
a
ab
Which components ?
b
a
ad
d
z
d
a
ac
c
ab + ad + ac + c d + b c
c
c
2 inverters
5 2-input AND gates
1 5-input OR gate
Total : 8 gates used
cd
d
b
bc
c
2-bit Unsigned Binary Comparator
From Handout 5
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 25

Implementing a Combinational Circuit on a New Chip
 By using Xilinx components that are AND, OR, NOT,…
2-bit
Unsigned Binary Comparator
Use them
Xilinx already has Comparators
You need an extra OR gate besides the comparator
Do not design your own Comparator
a
ab
b
a
ad
d
z
d
a
ac
c
c
c
cd
d
b
bc
c
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 26

Implementing a Combinational Circuit on a New Chip
 2-bit Unsigned Binary Comparator

By using Xilinx comparators
Which components ?
1 Xilinx 74_L85 Comparator
1 Xilinx 2-input OR gate
Total : 2 components used
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 27
Implementing a Sequential Circuit on a New Chip

 By using Xilinx components that are D, J-K, AND, OR, NOT,…
 The sequence detector from Handout 10
y1
x
J
y0
y1
Q
y2
Q
C
K
clock
y2
x
y0
J
x
y0
y0
y2
x
y0
Q
C
K
x
Q
y1
clock
y2
Least significant FF
x
y2
J
y0
x
y1
y2
K
C
Which components ?
y0
1 inverter
4 2-input AND gates
6 3-input AND gates
1 4-input AND gate
4 2-input OR gates
2 3-input OR gates
3 positive-edge triggered J-K FFs
most significant FF
Total : 21 components used
x
y1
x
Q
y0
y1
clock
y0
y1
CS 2204 Spring 2007
z
y2
Q
x
y2
y2
y2
x
Experiment 4 Lab 8
Page 28

Implementing a Combinational Circuit on a New Chip
 By using Xilinx components that are D, J-K, AND, OR, NOT,…
 The sequence detector from Handout 10
Xilinx does not have this sequence detector
We have to design our own sequence detector
y1
y0
most significant FF
x
J
y0
y1
Q
y2
Q
C
K
clock
y2
The design with
21 components
is implemented
x
y0
J
x
y0
y0
x
y2
x
y0
Q
C
K
x
Q
y1
y1
clock
y2
x
Least significant FF
x
y2
J
y0
x
y1
y2
K
C
y1
y0
Q
Q
y0
x
y2
y2
y1
z
y2
y2
x
clock
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 29

Xilinx FFs, Registers, Counters
 Many do not have direct set and direct clear
inputs

To avoid cases where both are active
 They have either

A direct set input
 Or

A direct clear input
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 30

Xilinx FFs, Registers, Counters
 Direct set and direct clear inputs

Asynchronous
 As we studied in class
• If the direct input is active, it affects the output immediately
 The name of the FF, register, counter has a
• “C” near the end if it is the direct clear input
► FDC : a D FF with an asynchronous direct clear input
• “P” near the end if it is the direct set (preset) input
► FDP : a D FF with an asynchronous direct set input
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 31

Xilinx FFs, Registers, Counters
 Direct set and direct clear inputs

Synchronous
 If the direct input is active, it affect the output when there is
the active clock edge
 The name of the FF, register, counter has an
• “R” near the end if it is the direct clear input
► FDR : a D FF with a synchronous direct clear input
• “S” near the end if it is the direct clear input
► FDS : a D FF with a synchronous set input
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 32

Xilinx FFs, Registers, Counters
 Some of them have an additional input

Clock Enable (CE)
 The name of the FF, register, counter ends with an “E”
 It controls the clock input
• If it is 1, the clock input gets the clock signal
► It can be clocked (stored)
• If it is 0, the clock input gets 0
► It cannot be clocked (cannot be stored)
 FDCE : A D FF with an asynchronous direct clear input
and a clock enable input
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 33

Xilinx FFs, Registers, Counters
 Clock Enable (CE)

FDCE : A D FF with an asynchronous direct clear input and a
clock enable input
CLR
CE
D
C
1
0
0
0
0
X
1
1
1
0
X
0
1
X
X
X
CS 2204 Spring 2007
0
X
Q
0 (Store 0)
0 (Store 0)
1 (Store 1)
NS
NS
Experiment 4 Lab 8
Page 34

Xilinx FFs, Registers, Counters
 Clock Enable (CE)

The clock enable is often connected the “Store” signal
CE is equivalent to
a
Storey0
Clock
y0
a
D
Storey0
y0
Q
C
Clock
CLR
Reset
Reset
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 35

The Ppm Term Project
 The black-box view
From the input devices
11
19
Ppm
To the output devices
Figure 1. The Ppm black box view.
 A large number of FFs are used !

We need to partition the Ppm based on major operations
 We have to obtain the operation diagram
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 36
The Ppm operation diagram
LD6-LD8 on the
FPGA board
show the
current state
Machine play block
Points Calculation block
Human play block
Input/Output Block
Play check block
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 37

The Ppm Term Project Partitioning
 We have observed the following major operations






Interfacing to the input/output devices
Handling human player’s play
Controlling display operations based on game rules
Calculating new player points
Determining the machine player play
Hint for general partitioning
 If you cannot figure out major operations, partition
one major operation at a time
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 38

The Ppm Term Project Partitioning
 Any other major operation ?

Control (time) the operations
 All other operations
CS 2204 Spring 2007
A Digital System
Experiment 4 Lab 8
Page 39

Digital Systems
 A digital system performs microoperations
 A digital system consists of digital circuits

A digital system consists of
 A data unit (datapath)

It performs microoperations
 A control unit

It controls the datapath
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 40

Digital Systems
 This first partitioning of a digital system is universal
Other digital systems/
Input/Output devices
Registers
ALUs
buses
control signals
status signals
Sequencer
Data Unit
(Datapath)
Control Unit
Figure 7. A large scale view of a digital system.
 A microprocessor is a digital system
 A computer is a collection of digital systems
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 41

Digital Systems
 The data unit has registers, ALUs and buses
to perform microoperations
Registers keep (store) data (operands and results)
 Arithmetic Logic Units (ALUs) perform additions,
subtractions, multiplications, ANDS, ORs, etc.
 Buses interconnect registers and ALUs

CS 2204 Spring 2007
Experiment 4 Lab 8
Page 42

Digital Systems
 The data unit is highly regular

Pieces of hardware repeated many times
 1-bit MUX repeated 32 times for a 32-bit MUX
 4-bit ADDer repeated 8 times for a 32-bit ADDer
 It is easier to design, test, modify,
manufacture, upgrade, service, maintain
regular hardware
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 43

Digital Systems
 The control unit determines the sequence of
microoperations based on status signals

The control unit goes through steps (states)
 In each state, it enables the microoperations of that
state to happen in the data unit based on the status
signals
• Microoperations must start at the right time with
correct inputs and end at the right time with correct
outputs
• Glitches, gate delays must be accounted for
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 44

The Ppm Term Project
 Ppm is a digital system !
 The Ppm term project partitioning

First partitioning of the digital system
 Control Unit
 Data Unit

core
Second partitioning (Data Unit partitioning)





Interfacing to the input/output devices core
Handling human player’s play core
Controlling display operations based on game rules core
Calculating new player points partially core
Determining the machine player play non-core
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 45

The Ppm Digital System Partitioning
Points Calculation
Block, Block 5
*
M1
M2
Datapath
(Data Unit)
(Experiment 5)
Machine Play Block
M3 Block 6
(Experiment 6)
Core
Play Check Block
Block 4
Input/
Output
Core
Human Play Block
*
means the block
is partially core
Block,
Block 2
Block 3 Core
Input/Output
Devices
Core
Control Unit, Block 1
(Block 1)
Figure 6. Block partitioning of the Ppm term project.
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 46

The Ppm Data Unit
 Experiment 5 after all circuits are moved to their appropriate
places
Macro 1, M1
Macro 2, M2
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 47

The Ppm Data Unit
 Experiment 6
Macro 3, M3
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 48

The Ppm Data Unit
 Block 2, Input/Output Block
64
Block 2
34
 It controls input/output devices on the FPGA board
and generates timing signals
 Three major operations

Controls Input/Output Devices
 I/O Buffer Subblock
 Display Subblock

Generates timing signals for the digital system
 Timing Subblock
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 49

The Ppm Data Unit
 Block 2, Input/Output Block
64
Block 2
34
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 50

The Ppm Data Unit
32-bit frequency divider
 Block 2, Input/Output Block
Timing
Subblock
I/O Buffer
Subblock
Display
Subblock
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 51

The Ppm Data Unit
 Block 2, Input/Output Block

Important outputs of the block
 Sysclk : System clock at 6Hz from the Timing Subblock
• Each state in the operation diagram is at least 1 system clock period
• The machine player at the course web site takes nine (9) system clock
periods to think and play !
 Rdclk : Random digit clock at 192 Hz from Timing Subblock
• Random Digit Generation Subsubblock in Block 4 uses it to generate the
random digit
 P1SEL : Four Player Select lines coming from SW1 – SW4, indicating
which position the human player plays
• The Human Play Block uses them
• The Play Check Block selects them
 P1add : A single line coming from SW8, showing Player 1 wants to add
• The Control Unit uses to blink the display played
 P1playsynch : A single line synchronized with the system clock indicating Player 1
wants to play
 P2playsynch : A single line synchronized with the system clock indicating Player 1
wants Player 2 to play
• It means either Player 1 examined the situation after playing or Player 1
does not want play the random digit and so wants to skip the play
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Experiment 4 Lab 8
Page 52

The Ppm Data Unit
 Block 3, Human Play Block
5
Block 3
2
 Very simple for this version of the term project


Makes sure the human player does not play on two or more
positions
Generates P1played and P1skip signals
 It is kept there so that in the future this block can
be used to have another machine player so that it
becomes machine vs. machine
CS 2204 Spring 2007
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Page 53

The Ppm Data Unit
 Block 3, Human Play Block
P1SEL
4
Human Play Block
Block 3
P1played
P1skip
P2playsynch
Core
Figure 12. The detailed view of the input and output signals of the Human Play Block.
5
Block 3
CS 2204 Spring 2007
2
Experiment 4 Lab 8
Page 54

The Ppm Data Unit
 Block 3, Human Play Block
The circuit that
generates the
P1skip signal
The circuit that ensures
only one position is played
by the human player
The MUX circuit
implements a gate
network as will be
discussed in class
The gate network
ensures only one
position is played
P1played is generated
if only one position is
played
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 55

The Ppm Data Unit
 Block 3, Human Play Block
 Important outputs of the block
 P1played : A single line indicating Player 1 has played on a
position
• It is 1 if only one of SW1 – SW4 is turned on
► The MUX circuit ensures only one position is played
 P1skip : A single line indicating Player 1 has skipped the
play
• The P2play line is used to generate P1skip
► If Player 1 turns on P2play, it means Player 1 does not want
play the random digit ≡ Player 1 wants to skip
► A buffer is used to rename the P2playsynch signal
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 56

Ppm Work for the Rest of the Semester
 Move circuits in Blocks 3, 4, 5 and 6 to their
appropriate places

In Experiments 2, 3 and 4
 Read the Term Project Handout

After all circuits are in their proper places, label
the components
 Last Xilinx component label in Block 5 : U150
 Complete Block 5

In Experiment 5
 Design Block 6

In Experiment 6
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 57

Block 3
 Read the Term Project Handout to get this
schematic
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 58

Block 4
 Read the Term Project Handout to get this
schematic
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 59

Block 5
U150
 Read the Term Project Handout to get this
schematic
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 60

Block 6
 Read the Term Project Handout to get this
schematic
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 61
Q/A
Do not leave the lab before your partners finish
► Help your partners complete today’s project
Read slides on the Ppm, Project Manager,
Schematic design and other related topics
Continue reading the Term Project handout
Think about the machine player strategy
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 62

Today’s Individual Xilinx Work
 We will study (analyze) the term project

We will use our knowledge of counters to modify a portion of
a term project schematic
 We will replace a 4-bit Xilinx BCD up counter (Divide-by-10 or
Modulo-10 counter) with our own circuits
 Read slides on the Ppm, Project Manager, Schematic
design and other related topics
 Help your partners complete today’s project
 Continue reading the Term Project handout

Move circuits in Blocks 3, 4, 5 and 6 to their appropriate
places
 In Experiments 2, 3 and 4

After all circuits are in their proper places, label the
components
 Last Xilinx component label in Block 5 : U150
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 63

Today’s Individual Xilinx Lab Work
1. Copy the exp3 folder and paste it in the
cs2204 folder as the exp4 folder

We will experiment with the Ppm schematics
2. Open the Ppm project in exp4
3. Look at the six Ppm schematics



If you copy a project completely as we did and then open
its schematics, the schematics will be all Non-Project
Therefore, close all these schematics and close the
schematics window
Then, open the schematics one by one on the Project
Manager window, by double clicking on the schematic name
on the upper left side
4. Place your team info on the schematics on
schematic 1 : ppm1.sch
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Page 64

Today’s Individual Xilinx Lab Work
5. Save schematic 1
6. Switch to schematic 4
7. Zoom into the upper right area, containing the
Random Number Generation Subsubblock
8. There is a Xilinx macro (a Xilinx Design Block, XDB)

A BCD Up Counter, CD4CE, in the subsubblock




It counts up 0 to 9, inclusive
• Its clock is always enabled (CE = 1)
• Its direct clear input is always inactive (CLR = 0)
It implements the BCD Up counter similar to the modulo-12
counter implemented in class
• We used a TTL LS chip : 74LS169
See ppm4.sch on the next slide
See the subsubblock in more detail on the slide that
follows
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 65
Today’s Individual Xilinx Lab Work


Ppm Schematic 4
Xilinx BCD Up
Counter
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Experiment 4 Lab 8
Page 66
Today’s Individual Xilinx Lab Work


Ppm Schematic 4
Xilinx 4-bit register
which is stored the
random digit when
Grd (Get Random
Digit) is raised to
1 by the control
unit when BTN1
or BTN2 is pressed
Xilinx BCD
Up Counter
Xilinx D FF is
Stored 1 on the
4-bit register
during the reset
state
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Page 67

Today’s Individual Xilinx Lab Work
9. Analyze the BCD up counter to determine how its
inputs and outputs are used

It counts up at the rate of Rdclk (Random digit clock)


Rdclk is generated in the Timing Subblock of schematic 2
 It is derived from Q0 which is one of the outputs of a
16-bit Xilinx binary counter, CB16CE, U63
 Q0 has the frequency of 192 Hz
Three outputs of the counter are stored on a Xilinx 4-bit
register
 The counter value is stored as the random digit when Grd
(Get random digit) is 1
 The rightmost output of the counter is not stored on the
register !
 If this output is connected to the register, the random
digit is always odd (1, 3, 5, 7 and 9)
 It is a problem of the Xilinx software and so to get
around it the register is connected Q7 from U63 in
schematic 2
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Page 68

Today’s Individual Xilinx Lab Work
9. Analyze the BCD up counter to determine
how its inputs and outputs are used

See the correspondence between this circuit and
your class notes


The Xilinx counter is an Up counter and so does not
have the U/D input
Its internal design is for BCD counting and so no
external gate is needed
• Do a Hierarchy Push and see how it is implemented
by Xilinx
• Do a Hierarchy Pop to close the internal circuit
schematic
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Experiment 4 Lab 8
Page 69

Today’s Individual Xilinx Lab Work
10. Perform functional simulations on the Xilinx
BCD counter

In order to simulate, we need to name the
outputs of the Xilinx counter



Output Q0 does not have a wire connected
• Connect a short wire to the output and name it
RDC0 where RDC stands for “Random Digit Counter”
Name the other three output as RDC1, RDC2 and RDC3
See the next slide for the outputs of the counter
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 70
Today’s Individual Xilinx Lab Work


Ppm Schematic 4
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 71

Today’s Individual Xilinx Lab Work
10. Perform functional simulations on the Xilinx
BCD counter

When you do the simulations




See slide 112 to learn how to supply the periodic clock
signal
You can start with any initial value (initial count), since
it is a counter,
Apply at least 13-14 clock cycles to observe the outputs
so that they cycle around
See the next slide that shows the simulation for 14
clock periods
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 72
Today’s Individual Xilinx Lab Work


The simulation window for the Xilinx BCD Counter
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 73

Today’s Individual Xilinx Lab Work
11. Search for the inputs and outputs of the Counter
by clicking on the Query window button on top of
the schematic sheet to confirm your findings in
part (9)
In the Signal/Bus mode of the SC Query/Find window that
will pop up
Determine the component that generates the input
 Rdclk
Determine the components that use outputs
 RDC1, RDC2 and RDC3
12. Delete the Xilinx BCD Up Counter in schematic 4


Do not delete the wires
Save schematic 4, ppm4.sch

See modified ppm4.sch on the next slide
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 74
Today’s Individual Xilinx Lab Work


Ppm Schematic 4
Xilinx
BCD Counter
deleted
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 75

Today’s Individual Xilinx Lab Work
13. Create space in the area by moving the wires in
schematic 4
14. Draw the gate network of the BCD Up Counter by
using your class notes in the same area in schematic
4

On paper, design the circuit by using your class notes

You will use a NAND gate to detect number 9 in Unsigned
binary (1001)
•
In class, number 12 in Unsigned Binary (1100) is detected
•
In class, we loaded (0001) to the counter
•
Use, the closest one, X74_161 which is equivalent to the
74LS161 4-bit Up counter
► It is an Up Counter and so does not have the U/D input
► It has an extra input : asynchronous direct clear

You will load (0000) to the counter

Xilinx does not have the equivalent of the 74LS169 chip used
in class
 It is not needed and so connect 1 permanently
► Its ENP and ENT inputs allow counting up
 They are not needed and so connect 1 to them permanently
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 76

Today’s Individual Xilinx Lab Work
14. Draw the gate network of the BCD Up Counter by
using your class notes in the same area in schematic
4

After the paper design is complete, move the design to the
computer



Place the components on the screen based on your paper
design
Wire the components based on your paper design
Label the wires (inputs and outputs)
• Name the components of the BCD Up Counter from left
to right and top to bottom starting at U114
► The last component label is U115


Save schematic 4, ppm4.sch
See modified ppm4.sch on the next two slides


First the BCD counter circuit
Then, the modified ppm4.sch
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 77
Today’s Individual Xilinx Lab Work


The BCD counter circuit in ppm4.sch
CS 2204 Spring 2007
BCD Up Counter
Experiment 4 Lab 8
Page 78
Today’s Individual Xilinx Lab Work


Ppm Schematic 4
BCD Up Counter
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 79

Today’s Individual Xilinx Lab Work
15. Perform an integrity test to check for
errors
16. Perform functional simulations on this BCD
Up Counter in schematic 4 to verify that it
is working


See slide 112 about supplying the periodic clock
signal
Make sure the circuit is beautified and the
schematic is saved again
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Experiment 4 Lab 8
Page 80

Today’s Individual Xilinx Lab Work
17. Do a Xilinx IMPLEMENTATION

Make sure there are no errors


Make sure the IMPLEMENTATION options are
changed so that a better IMPLEMENTATION is done
Read the Implementation Log File to confirm
that

The number of warnings 12
•
These warnings are OK, we can continue
CS 2204 Spring 2007
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Page 81

Today’s Individual Xilinx Lab Work
17. Do a Xilinx IMPLEMENTATION


Read the Implementation Log File to confirm
that
Read the Implementation Log File to confirm
that

The FPGA chip utilization is 89%
•
The Xilinx IMPLEMENTATION maps the design to 175
to 176 CLBs after an IMPLEMENTATION, a feature
peculiar to FPGA testing
 The conversion of the schematic to the bit file is
“randomized” to have a better mapping of the logic to
CLBs, but it leads to this situation
 That is why we fabricate the prototype chip before we mass
produce it to test the design one more time to make sure
the design is correct
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 82

Today’s Individual Xilinx Lab Work
18. Download the Ppm project to the FPGA chip and
play the game and to verify that the schematic
works correctly

If it does not work, inspect your circuit in Block 4 and
correct your circuit
19. Replace your BCD Counter with a Xilinx BCD
Counter
It is a Xilinx CD4CE component
Connect its input and outputs
Label it as U114
See modified ppm4.sch on the next slide
Do a Xilinx IMPLEMENTATION
Download the ppm project to the FPGA chip and play the
game and to verify that it works correctly
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 83

Today’s Individual Xilinx Lab Work
19. Replace your BCD Counter with a Xilinx BCD Counter
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Experiment 4 Lab 8
Page 84

Today’s Individual Xilinx Lab Work
20. Read slides on the Ppm, Project Manager,
Schematic design and other related topics at the
end
21. Help your partners complete today’s project
22. Continue reading the Term Project handout

Move circuits in Blocks 3, 4, 5 and 6 to their appropriate
places


After all circuits are in their proper places, label the
components


In Experiments 2, 3 and 4
Last Xilinx component label in Block 5 : U150
If necessary, download the other two versions of the term
project to refresh your memory
•
•
Ppm human vs. human : ppmhvsh
Ppm machine vs. machine : ppmmvsm
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 85

Understand Critical Wires
RD : 4 bits
 The random digit
DISP : 16 bits
 They represent the four position displays
 In Hex
 DISP15-DISP12 : the leftmost position display, PD3
 DISP11-DISP8 : position display PD2, etc
NDISP : 16 bits
 New DISP bits
 In Hex
NPDISP : 16 bits
 Display digits plus RD
PDPRD : 4 bits
 Display overflow bits after addition
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 86

Understand Critical Wires
Selplyr : 1 bit
 The current player
 If it is 0, it is the human player, otherwise, it is the
machine player
P1SEL : 4 bits
 The position played by the human player
P2SEL : 4 bits
 The position played by the machine player
PSEL : 4 bits
 Position Select bits of current player
ENCPSEL : 2 bits
 The number of the position played
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 87

Understand Critical Wires
BRWD : 4 bits
 Basic reward
 In Hex
 The digit played and minimum points earned
Brwdeqz : 1 bit
 BRWD is zero when it is 1
EQ : 4 bits
 The equality of the four displays to the digit played
NSD : 2 bits
 The number of similar digits, i.e. the adjacency information of the position
played
REGRWD : 8 bits
 The regular reward points calculated by only using adjacencies
 In Unsigned Binary
RDRWD : 8 bits
 The random reward points generated from a freely running counter
 In Unsigned Binary
RWD : 8 bits
 The reward points earned by the play after adding REGRWD and RDRWD
 In Unsigned Binary
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 88

Understand Critical Wires
P1PT : 8 bits
 Player 1 points
 In BCD
P2PT : 8 bits
 Player 2 points
 In BCD
NPT : 8 bits
 New player points for the current player
 In BCD
Ptovf : 1 bit
The points overflow
 if it is 1, the new player points is above (255)10
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 89

Understand Critical Wires
P1add : 1 bit
 Player 1 adds when it is 1
P1rdrwd : 1 bit
 Player 1 requests a random reward when it is 1
P2add : 1 bit
 Player 2 adds when it is 1
P2rdrwd : 1 bit
 Player 2 requests a random reward when it is 1
Add : 1 bit
 The current player adds when it is 1
P1skip : 1 bit
 Player 1 skips when it is 1
P2skip : 1 bit
 Player 2 skips when it is 1
P1played : 1 bit
 Player 1 played when it is 1
P2played : 1 bit
 Player 2 played when it is 1
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 90

Understand Critical Wires
Clear : 1 bit
 Clear FFs, registers, counters, etc. during reset in Block 2 and Block 4 so
that it can play again
Clearp2ffs : 1 bit
 Clears Player 2 FFs, counters and registers
Clff : 1 bit
 Clears FFs in Block 2 so that the next player can play if there is no overflow
Stp1pt : 1 bit
 Store Player 1 points
Stp2pt : 1 bit
 Store Player 2 points
Rdrwdsel : 1 bit
 Current player has requested a random reward when it is 1
Sysclk : 1 bit
 System clock of the operation diagram at 6 Hz to the digit played
S1 : 1 bit
 State 1 where when it is 1, the Ppm is in state 1
S4 : 1 bit
 State 4 where when it is 1, the Ppm is in state 4
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 91

Project Manager Actions and Reminders
 Make sure there is a CS2204 folder
 Make sure there is an experiment folder for
the current experiment

You can check the folder the current project is in
by selecting File -> Project Info
 Make sure the FPGA chip and its model are
correct when a new Xilinx project is created

You can check the FPGA chip and its model by
selecting File -> Project Type…
 The selections must be as follows
• The chip : Spartan
• The model : S10PC84
• Speed : 3
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 92

Project Manager Actions and Reminders
 If you copy a project completely and paste it as a
new project, its schematic files cannot be worked on
right away




After you open the schematics, they are all Non-Project
schematics
Close all the schematics
Close the schematics window
Open the schematics one by one on the Project Manager
window
 Double click on the schematic name on the upper left side for
each schematic file
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 93

Project Manager Actions and Reminders
 When you do the first Xilinx
IMPLEMENTATION or after clearing the
implementation data, you need to change
implementation options before clicking on
“Run” in the Implement Design Window

You can change the options by selecting Options…
in the same window and then
 Increase the Place & Route Level to the Highest Effort
on the “Options” window
 Click on the Edit Options… button for Implementation: in
the Program Options area of the “Options” window
 Click on Place and Route on the “Spartan Implementation
Options: Default” window
 Increase Router Options to 5 and 5 for both Routing
Passes and Delay-Based Cleanup Passes
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 94

Project Manager Actions and Reminders
 After a successful IMPLEMENTATION




The schematic files have a check mark next to them
The Design Entry button will have a check mark
The IMPLEMENTATION button has a check mark (after a
delay of minutes sometimes)
The PROGRAMMING button is highlighted
 If not, just click in anywhere in the Flow tab area of the
Project Manager window, it will be highlighted
 If the IMPLEMENTATION is not successful due to
errors, the IMPLEMENTATION button will have an
“X” mark

The error can be because of wrong chip selection or
schematic design errors
 Correct them then !
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 95

Project Manager Actions and Reminders
 After a Xilinx IMPLEMENTATION, read the
Implementation Log File for errors, warnings and
FPGA chip utilization

You can read the Implementation Log File by selecting
Reports -> Implementation Log File
 All No driver warnings must be corrected
• No Driver means, the wire is not connected to any
component output
 All Multiple drivers warnings must be corrected
• Multiple Drivers means, a wire is connected to multiple
component outputs
 Most No Load warnings can be ignored
• Because, the software warns that a component output is
not used, because you do not need the output
• But, if a component output is needed, and not connected,
then it is an error, the output must be connected to the
input of a component
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 96

Project Manager Actions and Reminders
 After performing several Xilinx IMPLEMENTATIONs, clear the
implementation data, by selecting Project -> Clear
Implementation Data

Back to back Xilinx IMPLEMENTATIONs use previous
implementation data that is unchanged to save time
 Over time, this implementation data becomes corrupt and the bit file
has errors
• Correct designs do not perform correctly on the FPGA board

Clearing the implementation data changes the implementation
options to the default ones





The schematic files will keep their check marks
The Design Entry button will keep its check mark
But, the IMPLEMENTATION button will have a question mark
The PROGRAMMING button will not be highlighted
The implementation options must be changed to the required ones again
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 97

Schematic Design Actions, Shortcuts &
Reminders
 Place team info on schematics

You can enter the team info by selecting File -> Table
Setup…
 Place your name & a partner name on Line1:
 Place names of the other two partners on Line 2:
 On Line3: place CS2204 – Section A/B/C/D/E/F – Spring 2007
 Press F2 to enter the Select & Drag Mode

Only, in this mode components can be deleted, rotated,
copied and pasted
 You can press ESC to enter the Select & Drag Mode
 Press F3 to get component library on screen



VCC is logic 1
GND is logic 0
To quickly locate a component, enter the first few letters of
the component in the bottom area of the SC Symbols window
 To locate XOR gates, just enter letter “X” and “O”
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 98

Schematic Design Actions, Shortcuts &
Reminders
 Press F4 to draw wires
 Press F5 to draw buses
 Press F7 to search for wires and components

To search for wires, select the Signal/Bus mode
 If the wire does not have a name, the software assigns one
that starts with a “$” symbol and ends with a “_” symbol
• Use the whole name to search for a wire

To search for a component, select the Instance mode
 If a component does not have a name, the software assigns one
that starts with “$I” symbols followed by a number
• Use the whole name to search for the component
 Press F8 to start simulation quickly
 Press F10 to refresh the screen
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 99

Schematic Design Actions, Shortcuts &
Reminders
 Press ctrl-c to copy a wire or a component selected


When components are copied, their labels are not copied !
You can copy from a schematic that belongs to another
project
 To open the schematic of another project, click on
button
in the upper left corner, then select the schematic file which
will be in another folder
 Press ctrl-v to paste a wire or a component
 Press ctrl-r/ctrl-l to rotate components right/left

Wires cannot be rotated !
 You can see how a Xilinx macro is designed (the
internal structure), do a Hierarchy Push, by selecting
Hierarchy -> Hierarchy Push
 You can close the macro internal design screen, by
selecting Hierarchy -> Hierarchy Pop
CS 2204 Spring 2007
Experiment 4 Lab 8
Page 100

Schematic Design Actions, Shortcuts & Reminders
 Unless otherwise stated, use Xilinx macros instead of designing
them to save time
 Use buffers to rename wires
 Do not use unnecessary input/output buffers
 Do not use unnecessary input/output pads
 If you copy and paste components, their labels are not copied
and pasted by the software

You will need to “source” the schematic file to copy and paste
component labels as explained in the Advanced Xilinx and Digilent
Features handout
 Xilinx does not have high density ROM memory components

16x1-bit and 32x1-bit
 They may not be used at all
• If needed, its usage is described on page 9 of the Advanced
Xilinx and Digilent Features handout
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Page 101

Schematic Design Actions, Shortcuts &
Reminders
 Drawing buses by using Draw Buses button on the left
side :


Ppm buses are type None
Individual wires of a bus must have names the same as the
bus name
 The indices of individual wires start at 0 and are up to the
number of bus wires minus 1
• Bus NPT has 8 wires : NPT7, NPT6, NPT5,…, NPT1, NPT0

If a component generates a bus, there is no need to draw
the individual wires of the bus, unless a components needs
those individual wires
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
Schematic Design Actions, Shortcuts &
Reminders
 Beautify the schematic for documentation purposes

Place components of different sub/blocks separate from
each other to recognize them
 Write Comments, draw lines and rectangles and label
sub/blocks to identify them on the schematic for
documentation purposes
• Use the Graphics Toolbox button on the left :

Label components appropriately
 Wire names follow application and block partitioning naming
requirements
• Except for wires that are connected IBUFs, OBUFs, IPADs and
OPADs
 Component names start with a U
• Except if it is a BUF, IBUF, OBUF, IPAD or OPAD
 To label a component, right click on the component and select
Symbol Properties…
• Give the name in the Reference: section of the Symbol Properties
window
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
Schematic Design Actions, Shortcuts &
Reminders
 Beautify the schematic for documentation purposes


Do not leave components unused
Draw short wires and label them with the same name
 To label wires double click on the wire and enter the name in
the Net Name: area of the pop up window






Draw wires without unnecessary turn
Draw wires without tangling
Draw wires around components/labels/names
Do not short circuit input lines
Do not short circuit output lines
Do not have labels/attributes/components overlap
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform integrity tests to catch simple
errors

You can do an integrity test of the current
schematic sheet, by selecting Options -> Integrity
Test for Current Sheet
 After the completion, a window may tell you to look at
the Project Manager window to read about warnings
detected, even if it says the test passed successfully
• Look at the Project Manager window, you will see warnings
in blue
• If the last line has the Schematic Contents OK line, there
is no need to correct anything
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

Press F8 to start simulation quickly
 You will see the SC Probes window :
 To select the input wires to be simulated, click on the
Stimulator tool button of the SC Probes windows :
 Then click on the input wires by precisely clicking on their
names to select them
• There will be a square gray box shown on the left side of the
input wire name
• Wires that have no name cannot be simulated, therefore, they
must be given names for simulation
• When selecting input bus wires, click on the bus wires in the
increasing index order : ABUS0, ABUS1, ABUS2,…
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Experiment 4 Lab 8
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

Press F8 to start simulation quickly
 You will see the SC Probes window :
 To select the output wires to be simulated, click on the Probe
tool button of the SC Probes windows :
 Then click on the output wires by precisely clicking on
their names to select them
• There will be a square gray box shown on the left side of
the output wire name
• Wires that have no name cannot be simulated, therefore,
they must be given names for simulation
• When selecting output bus wires, click on the bus wires in
the increasing index order : OBUS0, OBUS1, OBUS2,…
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

Press F8 to start simulation quickly
 You will see the SC Probes window :


To start the simulation, click on the Simulator button of the
SC Probes window :
Once you have the simulation window on the screen
 You will see the input wires listed and then the output wires on
the left side of the Logic Simulator window
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Experiment 4 Lab 8
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

Separate the input rows from the output rows by placing a
blank row between the input and output wires sets
 Click on the top output wire
 Make selections Signal -> Empty Rows -> Insert

Combine bus bits to reduce the number of rows
 Click on the top bus wire which has the lowest index (ABUS0)
 Press shift and simultaneously click on the highest order bus
wire (ABUS7) to select all the wires of the bus
• A turquoise rectangle covers the bus wires
 Right click on the turquoise rectangle and make the following
selections Bus -> Combine
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

In order to simulate the circuit, the input wires must be
first given new names
 Click on the Select Stimulators button :
• A keypad window will be shown
 Select an input wire by clicking on it (it will be covered by a
turquoise rectangle) and then click on any letter key on the
keypad, such as “q”
• To the right of the input wire, the new name “q” is shown
• To the right of “q”, the current value of the wire is shown
►
If it is a single wire, the value is Hi-Z
◊ This has to be changed to have correct simulations
► If it is a bus, the value is shown as capital letter “Z”
◊ This has to be changed as well for correct simulations
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
Schematic Design Actions, Shortcuts & Reminders
 Perform logic simulations to catch logic errors

To change the values of wires on the simulator window
 If it is a single wire, the value is Hi-Z :
• Just click on the Hi-Z line to make the value 0
►The value is shown to the right of name “q” as 0
• Click on the 0 value line again to make the value 1
►The value is shown to the right of name “q” as 1
 If it is a bus, the value is shown as capital letter “Z”
• Click on Logical States to give a value to the bus :
►The Stimulator State Selection window will be shown
• Click on the bus name, such as ABUS
• Enter an appropriate Hex value in the Bus State area, such as “FA”
► Appropriate means the Hex value must fit the width of the
bus : “FA” implies, the bus has at least eight wires
• Click on the Bus button of the Stimulator State Selection window :
►The value assigned is shown to the right of name “q” as “FA”
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
Schematic Design Actions, Shortcuts & Reminders
 Perform logic simulations to catch logic errors

To change the values of wires on the simulator window
 To have a clock signal as an input follow the steps below :
• Make sure the input signal is not renamed as “q”, “w” etc.
• Click on the input signal to select it
• Click on the Select Stimulators button :
• Click on Formula…
• Double click on C1: under Clocks
• Enter the following in the Edit Formula area :
• 100ns=H 100ns=L
► This means a periodic signal which is 100 ns 1 and 100 ns 0 is generated
► The periodic signal has a period of 200ns or a frequency of 5MHz
• Click Accept
• Click Close
• You will see the C1 button on the Select Stimulators window
highlighted
• Click on C1 so that the input signal is renamed C1
• Click on the Simulation Step button several times :
• You will see the periodic signal automatically generated and the
output values in response to that
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
Schematic Design Actions, Shortcuts &
Reminders
 Perform logic simulations to catch logic errors

Start simulating the circuit for different input combinations
 If the circuit has 4 or less inputs, then simulate the circuit for
all input combinations (test vectors)
• 16 or less number of input combinations (test vectors)
 If the circuit has more than 4 inputs, select a number of input
combinations (test vectors) then simulate the circuit for these
test vectors
• Which test vectors to choose is a very important task !


To simulate the circuit, click on the Simulation Step button
several times :
Observe the outputs
 If they are correct, try another input combination
 If wrong, return to the schematic and try to figure out why it
is wrong !
 If an output value is Hi-Z or Unknown, there is an error,
correct it
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Experiment 4 Lab 8
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
Schematic Design Actions, Shortcuts &
Reminders

Printing schematics
1) Double click on the Printer227 icon on your desktop and
wait about a minute to allow it to affect the printing
option
2) Zoom into an area of the schematic to print the area
3) Select File -> Print on the schematic window
4) Change the option to Current View Only on the Print
window
5) Click on Setup on the Print Window
6) Change the printer to HP Printer 8150 in Room 227
7) Click on Options to select Landscape printing if
necessary
8) Click OK as many times as needed to print the page
9) Print one copy of each area and then make copies of the
printed schematics for your partners
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

What to do if the testing on the board gives wrong
results even thought the design is correct ?
If the design is absolutely correct, here are the steps to
follow in sequence :
1)
2)
3)
4)
5)
6)
7)
8)
The FPGA board is turned on ?
SW9 is in the PROG position ?
The Bitronics Data Switch selects your PC ?
The FPGA type and model are correct ?
The implementation options are changed ?
There are not too many levels of folders to reach the project on
the PC ?
Clear the implementation data, close the software, restart the
software and do a new Xilinx IMPLEMENTATION

Does it work now ?

Delete the project, recreate the project, copy the schematic design
from the saved schematic file
Save the schematic file worked on in a separate folder

•
Does it work ?
•
Does it work ?
Download the zipped project from the course web site, unzip it, copy
the schematic design from the saved schematic file
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
What to do if the testing on the board gives
wrong results even thought the design is
correct ?
9) Repeat step 7, by using your partner’s working
schematic
10) Login to another PC and try steps 5 - 8
11) Ask from the TA to help you
a) The TA will login to your original PC and try steps 5 – 8
by using your schematic design and his/her S drive
b) The TA will login to another PC and try steps 5 – 8 by
using your schematic design and his/her S drive on the
new PC
c) The TA will inform the professor
12)If the project works on the second PC, inform
the lab supervisor, Mr. Keni Yip that the original
PC has a problem
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