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ECE 477
Digital Systems Senior Design Project
Fall 2008
Homework 6: Printed Circuit Board Layout Design Narrative
Due: Friday, October 10, at NOON
Team Code Name: ___MultiTouch Remote________________________ Group No. __4___
Team Member Completing This Homework: _KyungTae Kim________________________
e-mail Address of Team Member: ___kimk______ @ purdue.edu
NOTE: This is the third in a series of four “design component” homework assignments, each
of which is to be completed by one team member. The completed homework will count for
20% of the individual component of the team member’s grade. The body of the report should
be 3-5 pages, not including this cover sheet, references, attachments or appendices.
Evaluation:
SCORE
DESCRIPTION
Excellent – among the best papers submitted for this assignment. Very few
corrections needed for version submitted in Final Report.
Very good – all requirements aptly met. Minor additions/corrections needed for
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version submitted in Final Report.
Good – all requirements considered and addressed. Several noteworthy
8
additions/corrections needed for version submitted in Final Report.
Average – all requirements basically met, but some revisions in content should
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be made for the version submitted in the Final Report.
Marginal – all requirements met at a nominal level. Significant revisions in
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content should be made for the version submitted in the Final Report.
Below the passing threshold – major revisions required to meet report
*
requirements at a nominal level. Revise and resubmit.
* Resubmissions are due within one week of the date of return, and will be awarded a score of
“6” provided all report requirements have been met at a nominal level.
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Comments:
Comments from the grader will be inserted here.
ECE 477
Digital Systems Senior Design Project
Fall 2008
1.0 Introduction
The Mutlitouch Remote requires IR camera, video decoder, DSP, video encoder, LCD
monitor, SDRAM, voltage regulator and possible use of voltage level shifter. The BlackFin
DSP has ability to acquire video signal or generate RGB signal from its own. So it might be
possible to get rid of either video encoder or video encoder. Getting NTSC camera signal
through RCA jack, and output through VGA cable.
2.0 PCB Layout Design Considerations – Overall
I. CA-84A CMOS Camera [1]
a. CMOS camera that it generates NTSC signal.
b. Operating voltage 5V-15V
c. Current Compsumtion : [email protected]
II. ADV-7181B Video Decoder [2]
a. Take NTSC signal through RCA jack.
b. Output 4:2:2 YCrCb(The process only need grayscale image, microcontroller will
be fed only 4bits Y data.) or I2C interface
c. 3.3V analog, 1.8V digital core, 3.3V IO supply
d. Analog Interface Inputs: Track lengths should be kept to a minimum, and 75Ω
impedances should be used when possible. It is recommended to decouple each
power supply pin with 0.1uF and 10nF capacitors. The fundamental idea is to
have a decoupling capacitor within about 0.5cm of each power pin. Also, avoid
placing the capacitor on the opposite side of the PC board from the ADV7181B,
as doing so interposes resistive vias in the path. The decoupling capacitors should
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ECE 477
Digital Systems Senior Design Project
Fall 2008
be located between the power plane and the power pin. Current should flow from
the power plane to the capacitor to the power pin. Do not make the power
connection between the capacitor and the power pin.
e. Digital Outputs : Try to minimize the trace length the digital outputs have to drive.
Longer traces have higher capacitance, which requires more current, which causes
more internal digital noise. Shorter traces reduce the possibility of reflections.
Adding a 30 Ω to 50 Ω series resistor can suppress reflections, reduce EMI, and
reduce the current spikes inside the ADV7181B. If series resistors are used, place
them as close as possible to the ADV7181B pins. However, try not to add vias or
extra length to the output trace to make the resistors closer.
f. Digital Inputs : The digital inputs on the ADV7181B are designed to work with
3.3 V signals, and are not tolerant of 5 V signals. Extra components are needed if
5 V logic signals are required to be applied to the decoder.
III. ADSP-BF532 [3]
a. Details on Section 3.0
IV. ADV-7171 Video Encoder [4]
a. Get digital signal and convert into analog signal
b. Outputs R/G/B, VSync and HSync
c. The metallization gap separating device power plane and board power plane
should be as narrow as possible to minimize the obstruction to the flow of heat
from the device into the general board.
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ECE 477
Digital Systems Senior Design Project
Fall 2008
d. bypass capacitors should be installed using the shortest leads possible, consistent
with reliable operation, to reduce the lead inductance. Best performance is
obtained with 0.1 μF ceramic capacitor decoupling.
e. The digital inputs to the ADV7170/ADV7171 should be isolated as much as
possible from the analog outputs and other analog circuitry. Also, these input
signals should not overlay the analog power plane.
f. The ADV7170/ADV7171 should be located as close as possible to the output
connectors to minimize noise pickup and reflections due to impedance mismatch.
V. MT48LC32M 512M SDRAM [5]
a. Decoupling capacitors 0.1uF for every power line.
VI. Voltage Regulators
a. Detail on section 4.0
3.0 PCB Layout Design Considerations – Microcontroller
1) Powered by 1.2 V (from uC) and 3.3 V (from the voltage regulator)
2) Requires a 40 MHz crystal for a clock signal and a 32.768 KHz crystal for real time
interrupts. According to AN1259, the crystal need to be placed as close as possible.
3) Decoupling capacitors need to be close to the microprocessor as well.
4) Also needs connections to EEPROM, and possible use of FLASH ROM.
4.0 PCB Layout Design Considerations - Power Supply
a) The system needs 3types of input 1.8V, 3.3V and 5.0V. 1.8V and 3.3V are for
microprocessor and video encoder/decoder. 5.0V is for NTSC IR camera. Main
power source is going to be power supply from LCD screen. Assuming the range of
operating voltage is 12V~24V which is suitable input for voltage regulators.
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ECE 477
Digital Systems Senior Design Project
Fall 2008
b) Recommend 0.luF for input decoupling capacitor, recommend 10uF for output
decoupling capacitor.
5.0 Summary
According to the AN1259, decoupling capacitor needs to be placed as close as the
microprocessor. The PCB need enough trace width for the power line, such as line from
voltage regulators, and power supply.
Be sure to read Motorola Application Note AN1259 (posted on course web
site) before you begin your PCB layout.
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ECE 477
Digital Systems Senior Design Project
Fall 2008
List of References
[1] “CMOS Camera CA-84A”, SparkFun,
http://www.sparkfun.com/datasheets/Sensors/Imaging/CA-84AC.pdf
[2] “ADV-7181B Multiformat Video Decoder”, Analog Device,
http://www.analog.com/static/imported-files/data_sheets/ADV7181B.pdf
[3] “BlackFin 532 Embedded Processor”, Analog Devices,
http://www.analog.com/static/imported-files/data_sheets/ADSP-BF531_BF532_BF533.pdf
[4] “ADV-7171” Video Encoder”, Analog Devices, http://www.analog.com/static/importedfiles/data_sheets/ADV7170_7171.pdf
[5] “MT48LC32M
512M
SDRAM”,
Micron
Technonlogy,
http://www.ic-on-
line.cn/IOL/datasheet/MT48LC128M4A2_9374.pdf
IMPORTANT: Use standard IEEE format for references, and CITE ALL REFERENCES
listed in the body of your report. Provide “live” links to all data sheets utilized.
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