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Fresh Beets Graphic Equalizer Kodi Hildebrandt Colby Renfro Steven - - PowerPoint PPT Presentation
Fresh Beets Graphic Equalizer Kodi Hildebrandt Colby Renfro Steven - - PowerPoint PPT Presentation
Fresh Beets Graphic Equalizer Kodi Hildebrandt Colby Renfro Steven Wooldridge EGGN 383 November 30, 2012 Colorado School of Mines Overview Overview Input: Audio Signal Output: Graphic Equalizer 1. Provide audio signal to FFT
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Overview
- Input: Audio Signal
- Output: Graphic
Equalizer 1. Provide audio signal to FFT chip
- 2. Poll FFT
- 3. Process data
- 4. Output to display
- Interrupt Driven
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Hardware Setup
- 1 – MSGEQ7 Graphic Equalizer Display Filter
- 1 – HCS12 microcontroller
- 1 – MAX7219 SPI LED Driver
- 1 – 8x8 LED Matrix
- Various Resistors & Capacitors
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Schematic
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Schematic
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Schematic
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Schematic
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Psuedocode
Main { Initialize SPI Initialize A/D Initialize PTT for Input/Output Initialize Display Initialize RTI for 60Hz Rate, Interrupts } RTI Interrupt { Clear Interrupt Flag //Read FFT Reset FFT Chip FOR (i=0; i<7, i++) { Strobe Low Pause 50 uS Read A/D Register Strobe High } Average Last Two frequencies to achieve 8 discrete values //Write to Display //Scan through frequencies FOR (i=0; i<8, i++) { Map Magnitude from 0-255 to 0-8 Write Magnitude through SPI } }
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MSGEQ7 (FFT) Timing
"Seven Band Graphic Equalizer Data Sheet." Mixed Signal Integration, 2004. Web. 11 Nov. 2012. <https:/ / www.sparkfun.com/ datasheets/ Components/ General/ MSGEQ7.pdf>.
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Continuous & Discrete Signals
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MAX7219 LED Driver
"MAX7219/ MAX7221: Serially Interfaced, 8-Digit LED Display Drivers." Maxim Integrated. N.p., 2003. Web. 29 Nov. 2012. <http:/ / datasheets.maximintegrated.com/ en/ ds/ MAX7219-MAX7221.pdf>.
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