1. Presentation 3 – Team 6 Brian Gallert Detailed Block Design
User Interface
Microprocessor
Brian Gallert

2. User Interface Block Diagram
120 VAC
To System
ON/OFF
Push Button
5 VDC
Base Current/ Gate Voltage Rotary Dial
Left/Right Toggle Switch
To System
Device
Rotary Dial
To Microprocessor
Collector Volts
Rotary Dial
Current scaling
Rotary Dial
Series Res.
Rotary Dial
# of Steps
Rotary Dial
Brian Gallert

3. User Interface Architecture
Base Current/Gate Voltage Increments
Power
Device Tested
Series Resistance
On/Off
100uA/ 100mV
MOSFET
10uA/ 10mV
1mA/ 1V
1kΩ
PNP
100Ω
10kΩ
Left / Right Switch
10mA/ 10V
JFET
1uA/ 1mV
10Ω
100kΩ
NPN
1MΩ 1Ω
100nA/ 100uV
100mA/ 10V
10MΩ
Device Under Test
Left Right
Collector Voltage Scaling
Current Scaling
Number of Steps C C
Half B B
100uA/ DIV 2 3
10uA/ DIV
1mA/ DIV 1 E E 4
1uA/ DIV
10mA/ DIV
Reset
Full
Zero
On/Off
Activate # of Steps
Brian Gallert

4. User Interface Component Selection
Device to be tested
4 position 3 pole rotary dial
Base Current/Gate Voltage Increments
5 position 1 pole rotary dial
Series Resistance
8 position 1 pole rotary dial
Collector Voltage Scaling
Rotary Dial directly connected to potentiometer
Current Scaling
Number of Steps
4 position 1 pole rotary dial
Brian Gallert

5. User Interface Bill of Materials
Part
Part Description
Company
Part #
Quantity
Price
Push Button
Red, ON/OFF Button
Jameco
315483CC 1
$1.29
Yellow, Activate # Steps
315521CC
Momentary Push Button
White, Reset
315467CC
Toggle Switch
1 pole, 2 position switch to choose between left or right device
76241CC
$1.49
Rotary Dial
4 position, 3 pole switch to select device to be tested
101565CC
$1.95
8 position, 1 pole switch to select increments, series limiting resistance, and current scaling
101531CC 3
$1.09
6 position, 2 pole switch to select number of steps
101573CC
$1.35
Knob to connect to dials
Black with position marker can connect to dials
265009CC 6
$0.69
Brian Gallert

6. User Interface Signals to Micro
Device to be tested – Pins 11 and 12
NPN – 00 (Not Connected)
PNP – 01
N-Channel MOSFET - 10
N-Channel JFET - 11
Base Current/Gate Voltage Increments – Pins 16, 17, 18
10 uA/10mV – 000 (Not Connected)
20uA/20mV – 001
50uA/50mV – 010
100uA/.1V – 011
200uA/.2V – 100
500uA/.5V – 101
1mA/1V – 110
2mA/2V - 111
Brian Gallert

7. User Interface Signals to Micro
Reset – Pin 1
When pressed, sends a pulse to micro and restarts
Activate Number of Steps – Pin 15
Sends a 1 to the Microprocessor initiating Selectable # of Steps
Select Number of Steps – Pins 13, 14
1st Step – 00 (Not Connected)
1st and 2nd Step – 01
1st, 2nd and 3rd Step – 10
1st, 2nd, 3rd, and 4th Step - 11
Brian Gallert

8. User Interface Switches to System
Left/Right Switch
Switches between testing device on left socket and right socket, engages one or the other
Collector Voltage scaling
Connected to potentiometer to scale the collector voltage from 30V (full) – 0 V
Series Limiting Resistance
Selects between 8 different resistances to limit the current flowing to the collector of the device under test
Brian Gallert

9. User Interface Switches to System
Device to be tested
NPN – uses 2 of the 3 poles of switch to
Send positive Collector Voltage to device under test
Send positive Base Current to device under test
PNP – uses 2 of the 3 poles of switch to
Send negative Collector Voltage to device under test
Send negative Base Current to device under test
MOSFET – used 2 of the 3 poles of switch to
Send positive Drain Voltage to device under test
Send positive Gate Voltage to device under test
JFET – uses 2 of the 3 poles of switch to
Send negative Gate Voltage to device under test
Brian Gallert

10. User Interface Switches to System
ON/OFF
Allows power from outlet to turn on curve tracer
Current Scaling
Can be used to scale the collector voltage flowing through device under test
Allows for better resolution of the curves
Brian Gallert

11. User Interface – Analog DFM Plan
Sub Circuit
Type
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Analog Switches
Contact Type
Contact Impedance
Current Contact Rating
Semicond Package & Heatsink
1. Push Button
On/off
30 mΩ 3A
Rectangular Panel Mount
2. Toggle Switches
40 m Ω 4A
3. 8 position 1 pole dials
Make before Break
30 m Ω
.3A
Circular Panel Mount
4. 4 position 3 pole dials
Make Before Break
Brian Gallert

12. Microprocessor Block Diagram
5 V
Activate # of
Steps
Analog Input Collector Voltage
PIC 16F876
Base Current/ Gate Voltage Rotary Dial
Device
Rotary Dial
Voltage or Current Selector
(8 bit number)
Reset
Analog Input Base/Gate Voltage
# of Steps
Rotary Dial
From User Interface
Brian Gallert
Clock

13. Microprocessor Architecture Layout
Brian Gallert

14. Microprocessor Component Selection
PIC16F876
Clock
Low Profile 4 Mhz Crystal
pF Capacitors to oscillator pins 9 and 10
Analog Inputs
In series with 1kΩ resistor
Voltage divider to maintain at 0-5 V level
Brian Gallert

15. Microprocessor Analog Input DFM
Collector voltage input range 0 – 34.5 V
Acceptable microprocessor voltage input range V
Need voltage divider to scale to less than 5.5 V
Choose Vout as 4.5V
R1 as 1 k
Vin = 34.5 V (worst case)
Therefore, R2 = 150
For 10% tolerance worst case
R1 = 900
R2 = 165
Vin = 34.5
Vout = 5.35 < 5.5V
Vin
Vout
Brian Gallert

16. Microprocessor Bill of Materials
Part
Part Description
Company
Part #
Quantity
Price
Processor
PIC16F876
Jameco
193367CC 1
$7.89
4Mhz Crystal
Low profile crystal
137832CC
$.99
24pf Capacitor
Surface Mount capacitors connected to clock input 2
PCB
Fiberglass board to mount clock and processor
$10.00
1k Resistor
Surface Mount resistors to place in series with analog inputs
200 Resistor
Surface Mount resistor to place in parallel with analog input for the collector voltage
.1uF radial lead capacitor
Capacitor to protect processor- Pins across ground and +5V
Brian Gallert

17. Microprocessor – Analog DFM Plan
Sub Circuit
Type
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Task 8
Task 9
Task 10
Voltage Divider
R tolerance
Sampling time
Min Acquisition time
Specified Acquisition Time
Analog to Digital Conversion
1.6us
Capacitor selection
Capacitor tolerance
Acceptable cap range
Range with tolerance
Output Impedance
FOSC
Noise or Ripple
Semicond Package & Heatsink
Crystal Cut
Quartz Crystal
24 pf
20%
15 pf – 68 pf
19.2 pf-28.8 pf
4 Mhz
Metal Can
Brian Gallert

18. Micro DFM – DC Drive Analysis
Dig
Device
Output
Type
Input Type
Tech Type
DC Drive Device Parameters
Vil
max
Vih
min
Iil (-)
Max
Iih
Vol
Voh
Iol
Ioh (-)
Min
Vhyst
Checked
PIC16F876
STD
CMOS
.8V
2.0V
1uA
-1uA
0.6V
3.8V
15mA
-15mA
N/A
Brian Gallert

19. Micro DFM – Timing Analysis Table
Dig Signal
Output
Type
Input Type
Timing Parameters
Other
Tsu
Setup Th
Thold
Marg
Fmax F
Tpulse
Min
Checked
Device Under Test
Std
.1us
.9us
4 Mhz
Base Current
4Mhz
Number of Steps
Current Selector
Brian Gallert

20. Microprocessor PCB layout
Brian Gallert

21. Summary of work left User Interface Microprocessor
Determine pin out for mechanical switches to entire system
Assemble proto-type
Microprocessor
Write the program to accomplish task
Specify the output to the base current generator
Finish proto-type assembly
Brian Gallert