homework 5: theory of operation and hardware design narrative · intel atom d525: main processor of...

ECE 477 Digital Systems Senior Design Project 8/09

Homework 5: Theory of Operation and Hardware Design Narrative

Team Code Name: ____GNMS______ Group No. ___6___

Team Member Completing This Homework: ______Jason Rice______

E-mail Address of Team Member: ____jmrice____ @ purdue.edu

NOTE: This is the second in a series of four “design component” homework assignments, each of which is to be completed by one team member. The body of the report should be 3-5 pages, not including this cover page, references, attachments or appendices. Evaluation:

SCORE DESCRIPTION

10 Excellent – among the best papers submitted for this assignment. Very few corrections needed for version submitted in Final Report.

9 Very good – all requirements aptly met. Minor additions/corrections needed for version submitted in Final Report.

8 Good – all requirements considered and addressed. Several noteworthy additions/corrections needed for version submitted in Final Report.

7 Average – all requirements basically met, but some revisions in content should be made for the version submitted in the Final Report.

6 Marginal – all requirements met at a nominal level. Significant revisions in 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. Comments:Comments from the grader will be inserted here

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1. Introduction

Our project is a touch surface with a projector display, video camera touch capture, and

application computing. The touch surface will need to interface these three concepts, as well as

extra peripherals. A processor needs to compute application data. This data will be need to be

visually displayed using the projector, and the human touches will be captured using a simple

video camera. A micro-controller will be integrated into the entire design to communicate extra

peripherals and user inputs with the motherboard.

1. Theory of Operation

The touch surface circuit design is composed of two major sections: the motherboard

and the micro-controller (see Appendix A for block diagram). The motherboard interfaces

with all of the complex circuitry dependent on the Intel processor, and the micro-controller

interfaces with all of the simple circuitry not directly dependent on the Intel processor. Complex

circuitry consists of video capture, video projection, and audio. Simple circuitry consists of the

temperature sensor, user controls (power, brightness, volume), and fan speed. Also, an array of

infrared LEDs must be organized along the perimeter of the display. These produce the lightning

necessary to capture human touches. Both the micro-controller and the motherboard are powered

by a power supply unit (PSU).

PSU [3]:

● Provides power to the motherboard and micro-controller.

● Multiple power lines of 3.3, 5, and 12V outputs.

● 3.3V from the SATA power plug will be used to power the micro-controller.

● 12V from the 4-pin ATX12V will be used to power the IR LEDs [2] (see Appendix A for

IR LED diagram).

● Normal 24-pin ATX and 4-pin ATX connectors to power the motherboard devices (CPU,

CPU fan, RAM, etc.)

Intel Atom D525:

● Main processor of the touch surface for software input and output and audio output.

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● Takes input from the Playstation Eye via USB.

● Outputs software visuals to the projector and audio to a 2.5mm audio connector.

● Powered by the PSU and On/Off functionality is controlled by the micro-controller.

Atmel AT32UC3B164 Micro-controller [1]:

● Requires 3.3V power source from PSU.

● Receives user input for projection brightness, On/Off, and audio volume via GPIOs.

● Transmits user input data to the motherboard via USB.

● Controls a projector brightness control LED and fan speeds via PWMs.

● Takes input from external temperature sensor via an ATD in order to control fan speed.

Playstation Eye:

● Sends video capture data to the motherboard via USB.

Epson EX30 Projector:

● Receives video data via VGA from the motherboard.

2.5mm Audio Jack:

● Outputs audio via a 2.5mm connection

IR LEDs:

● Powered by ATX12V connector from the PSU [2].

● 12V (11A) source chosen because our IR LED array (see Appendix A for IR LED

Diagram) will feature 27 parallel lines with 6 LEDs in each line.

● 11A / 27 = .407A... This will provide sufficient current as one IR LED parallel line draws

100mA at maximum.

● 12V / 6 = 2V... This will provide a sufficient amount of power as the forward current at

2V is 11 mA. With 11 mA, the relative radiant power (luminosity intensity) is roughly

twice the standard [2]. This will provide the ideal amount of IR light which should make

our video capture more accurate.

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Temperature Sensor:

● Gathers temperature data and transmits to micro-controller via an ATD converter.

On/Off Button:

● Transmits On/Off signal to the micro-controller via one GPIO.

Brightness Rotary Pulse Generator:

● Transmits increases and decreases via 4 GPIOs of the micro-controller to handle

projection brightness.

Volume Rotary Pulse Generator:

● Transmits increases and decreases via 4 GPIOs to the micro-controller in order to handle

audio volume.

Projector Brightness Control LED:

● Receives PWM signal from the micro-controller to send infrared signal to the projector in

order to control display brightness.

Rexflo 250 Fans:

● Receives fan RPM speed via 1 PWM from the micro-controller.

2. Hardware Design Narrative

The Atmel AT32UC3B164 includes GPIOs, PWMs, ATDs, and USB. These were the main

requirements of our entire circuit (see Appendix A for micro-controller pin assignment).

GPIO:

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● One GPIO will be used to receive data from an On/Off button.

● 4 GPIOs will be used to receive data from a display brightness RPG. The RPG requires 4

GPIOs.

● 4 GPIOs will be used to receive data from an audio volume RPG. The RPG requires 4

GPIOs.

PWM:

● One GPIO pin is to be used as an output PWM to control a projector brightness control

LED.

○ PWM is useful in order to control the frequency at which the LED emits infrared

light . This mimics the functionality of a remote control in order to control the

projector.

● Another to control the rotation speed of two 250mm case fans.

○ PWM is useful in order to control the frequency of power output which can be

used to regulate fan speed. This works well because the frequency of the PWM

output correlates with fan speed.

ATD:

● One GPIO pin is to be used as an ATD converter which receives input from a

temperature sensor that monitors temperatures inside of the packaging.

○ The temperature sensor outputs data in the form of an analog signal. This must be

converted to a digital signal that the micro-controller can interpret.

USB:

● The two USB pins are to be used to send user input data (from the display brightness

RPG, the volume RPG, and the On/Off button) to the motherboard.

○ USB is the simplest and easiest way to transmit data to and from a motherboard.

3. Summary

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An important part of product design is considering the impact and functionality of

included features. Each major unit in our circuit plays an important role. The processor controls

applications, the projector produces visuals, the micro-controller controls extraneous features,

and the camera controls human touch capture. Fully integrated, the system will work as a single

functioning unit. The user will never have to know the inner workings of a single part. The

external functionality will provide everything the user wants and needs. This is what defines a

completed product.

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List of References

[1] Newegg (2012, Feb. 15) Intel BOXD525MW Intel Atom D525 [Online]. Available: http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442

[2] MDFly (2012, Feb. 15) 5mm 850nm IR Infrared LED Pack of 10 [Online]. Available: http://www.mdfly.com/index.php?main_page=product_info&products_id=124

[3] Newegg (2012, Feb. 15) RAIDMAX RX-380K 380W ATX12V Power Supply [Online]. Available: http://www.newegg.com/Product/Product.aspx?Item=N82E16817152019

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http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442





















http://www.mdfly.com/index.php?main_page=product_info&products_id=124














































Appendix A: System Block Diagram

Figure 1: Block Diagram

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Figure 2: IR LED Diagram-9-


Figure 3: Atmel AT32UC3B164 Micro-controller Pin Functionality and Assignment

Pin # Type Function In/Out To/From

1 GND GND - GND

2 GPIO (JTAG) - In/Out -




6 Core Power Micro Power In PSU

7 GPIO ATD In Temperature Sensor

8 GPIO On/Off Control In On/Off Button

9 GPIO - In/Out -

10 GPIO - In/Out -

11 GPIO PWM Out Reponse LED

12 GPIO PWM Out 250mm Fans

13 Analog GND GND - GND

14 Analog Power Micro Power In PSU

15 Analog Power Micro Power In PSU

16 Voltage Regulator Power

Power Out Motherboard

17 Voltage Regulator Power

Micro Power In PSU


19 GND GND - GND

20 GPIO - In/Out -

21 GPIO - In/Out -

22 GPIO (Oscillator) - In/Out -


24 I/O Power Micro Power In PSU

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25 GPIO Brightness Control In Brightness RPG




29 GPIO - In/Out -



32 GPIO (High Drive) - In/Out -





37 GND GND - GND

38 USB + Transmit User Input Out Motherboard

39 USB - Transmit User Input Out Motherboard

40 USB VBUS On/Off Set USB On In PSU

41 PLL Power Micro Power In PSU


43 GPIO Volume Control In Volume RPG




47 Reset - In -


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