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 chip 2. Poll FFT 3. Process data 4. Output to display • Interrupt Driven

Hardware Setup • 1 – MSGEQ7 Graphic Equalizer Display Filter • 1 – HCS12 microcontroller • 1 – MAX7219 SPI LED Driver • 1 – 8x8 LED Matrix • Various Resistors & Capacitors

Schematic

Schematic

Schematic

Schematic

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 } }

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>.

Continuous & Discrete Signals

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>.

Questions?