Low Power FM Receiver Andrew Young November 17, 2008.
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Low Power FM Receiver Low Power FM Receiver Andrew Young November 17, 2008
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Transcript of Low Power FM Receiver Andrew Young November 17, 2008.
Low Power FM ReceiverLow Power FM Receiver
Andrew YoungNovember 17, 2008
OverviewOverview
Project Inspiration RequirementsDifferencesDesign Block DiagramDesign SchematicOperational FlowchartLCD LayoutQuestions
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InspirationInspiration2008 IEEE Student Contest
◦ Objective: Create low power FM radio receiver ◦ Can use commercially-available IC subsystems
Senior Design Project◦ Competition between two teams◦ Goal is lowest power consumption
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Design Requirements Receive FM radio from 88.1 to 107.9 MHz Output audio at > 4mW per channel to standard 32-
Ohm headphones (33-Ohm resistors used for testing) Adjustable volume/station Interact with user via LCD interface Entire design implemented on one PCB
Competition Testing: One supply source, < 15V DC Design allows for internal circuit inspection
Optional Extras: Display RDS data (station name, artist, song title) Any extra features (signal strength, station presets,
menu) My own customization – video games, easter eggs, etc.
DifferencesWhat is different about this
design compared to the senior design project?◦Extra features – Something cool to
add which takes advantage of already-existing components, such as the attached LCD and joystick (video game, perhaps?).
Design Block DiagramDesign Block Diagram
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FM Receiver IC
(Si4703)
Microcontroller
(ATMega32)
LCD/User Interface104.1
Headphone Amplifier
Schematic - Page 1Push Buttons
FM Receiver
ATMega32
Switching Power Supply
Voltage Adjustment
LCDPort A
Port B Audio L/R
Battery Output
Si4703 Comm
Schematic - Page 2Batteries (2x AA)
Clock Generator Headphone Jack
Audio Amplifier
Gain Adjustment
Potentiometers Noise Suppression
Input Coupling
ESD Protection
Audio L/R
Low Voltage Input
On/Off Switch
AVR Application Development
Codevision AVR IDE (Evaluation) ◦Limited to 2kB code size◦Built-in libraries (LCD, I2C, Power-
Save)
AVR Studio 4.0 ◦Used to debug and set clock rates,
voltage levels, fuses
Operational FlowchartOperational Flowchart
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Power onAVR
Initializes Receiver &
LCDSet to
Default Station & Volume
Receive RDS Data
Interrupt When Button Pressed
Determine Button Pressed
(Volume Up or Down, Tune Up or Down)
Receive Signal
Strength
Output Signal & RDS to
LCD
Send Appropriate Signal to IC to Change Volume/Station
Send Appropriate Signal to Receive Current
Volume/Station
Translate Data to LCD Output
Return from Interrupt
Idle
Interrupt
LCD LayoutLCD Layout
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104.1 - KZRZArtist – Song NameSig. █ █ █ █Vol. █ █ █ █ █ █ █ █ █
SummarySummaryDesigning Low-Power FM Radio Receiver w/ Inspiration: Senior Design CompetitionExtras: Features not required by the senior
design project, such as a video game using the 4x20 LCD and the attached joystick.
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QuestionsQuestions
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ATMega32 AVR
Silicon Labs Si4703
Headphone Amplifier – MAX9725
