- 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

Sunday, May 31, 2009

Arduino Controller & DAC

The DAC is a kit from TwistedPear Audio, based on the WM8741.
2-wire I2C connection (plus GND)

Inside the OPUS DAC: Leftmost is the toroid transformer inside a tin can. Middle is a dual DC power supply, rightmost are 3 boards stacked: top is the SPDIF receiver, middle is the asynchronous re-sampler and re-clocker board and bottom is the DAC board based on the Wolfson 8741.

Detail of the 2-wire I2C connection to the DAC board.

Detailed connection diagram

Arduino I2C connections are analog pin 4 and 5

1 comment:

Anonymous said...


Very nice post, I'm in the process of building a similar project but with some added complexity and...

...I'm having problems with the Detailed connection diagram you show in this post. I have a dual-mono configuration and I'm using also 2-wire I2C with Arduino Uno R3.
How can I contact you about this project? I have a diagram of my dual-mono with upsampler I want to send you so you can input some suggestions. My email is

P.S: I also did some modifications to the code you provide. It would be wonderful if someone could help me review it.

Thank you very much in advance...

All the best