- 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

Thursday, April 23, 2009


I've been using 5V I2C into OPUS which is a 3.3V device. So far it has worked, but I am going to find out from Wolfson if the device is 5V tolerant. However, I think it is safer to use the pull-up resistors referenced to 3.3V instead of the 5V. The 3.3V reference in Arduino can supply 50 mA. I'm going to check if this is sufficient.

Update: I've attempted to make the change to 3.3V (by changing the position of the pull-up resistors) and although everything works as before it is not yet the right solution because Arduino enables the pull up resistors internally. See post on final solution.

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