- Support for 4x20 LCD Display and large number display
- Brightness and contrast adjustment with remote
- (OPUS/Wolfson WM8741) DAC volume control: remote and rotary encoder
- (OPUS/Wolfson WM8741) DAC random filter selection 1 to 5 with remote
- (OPUS/Wolfson WM8741) DAC upsampling selection (L, M, H -this is the OSR setting)
- I2C level shifting (5V to 3.3V)
- Optimized power-up sequence

Friday, March 20, 2009

Why Rotary Encoder?

One of the main functions of a controller for audio is to control volume. Typically, volume is controlled with a potentiometer on the analog audio signal. But we want to use a controller to control another device that will control the volume. For example, controlling the digital volume capabilities of a modern DAC such as the Wolfson 8741 or audio volume chips such as TI PGA2320

A rotary encoder is a device that will keep on turning (there is no maximum or minimum) producing a signal with "clicks" indicating clockwise motion or counter-clockwise motion as shows in the following diagram

Why use a rotary encoder instead of a potentiometer? A rotary encoder will allow you to:
  • Use a preset volume level every time you turn on your stereo system (without having to turn a knob to a preset position)
  • Use an IR remote and a knob on the same system (without having a motor move the knob)
  • Change the sensitivity of the adjustment in software
  • Add a volume offset in software

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