1st test: Voltage divider 4K7-4K7 using TPS56637 5V 5A drop-down circuit.

ADC readings for voltage-divider:

9VDC wall adapter, 63-66
XP-581 set at 9VDC, 61-64
XP-605 set at 9VDC, 62-64

(Elenco desktop power supplies)

Naturally the pots jitter a bit more than the fixed divider.

Game plan:
1. remove the PWM and use a fix resistor for backlight.
2. feed the TPS56637 using a 9-12V battery.
3. try using 2 separate TPS56637 circuits:
- 1 for ADC (all inputs).
- 1 for PWM and LCD (all outputs).

The one for inputs "might' be replaced with an ordinary 7805 later. I don't need a lot of current to read pots, switches and encoders.