Nokia LCD Version
I downloaded the Adafruit Nokia LCD Libraries.
At 5v the LCD contrast was uncontrollable.
Assuming the LCD would be 5v tolerant (really I should have put serial 10k resistors in the data lines) I just powered it with the 3v3 Arduino supply.
It worked fine.
If I wire the CE or CS line low then I only need 4 outputs from the Arduino but I have not told the library as of yet (i.e. have not worked out how to do it).
Mostly a search and replace of "uView" for "display" but there were differences.
As the Nokia display is an extra 20 pixels wide I increased the data area width from 41 pixels to 61 pixels.
Here is the Nokia working with the 0-3v 1 kHz square wave signal:
The frequency does seem to be a little off (~5%)? Fixed it by timing every sample run:
For the above test:
- Sample frequency: 62437 Hz
- Nominal bandwidth: 500 Hz
- Number of samples: 249
- Maximum frequency: 6000 Hz
- Frequency bins: 61
- Noise floor <-30 dB
- Cycle time 760 ms
At 760 ms this is about as a much as this algorithm can do!
If I want more I will have to migrate to DFT.