Sorry for delay, a nasty cold put me "out-of-the-grid" for few days.
CBDBv2 bord was designed as a educational platform to be used for many tutorials and experiments hence the different and sometime redundand functions that you might find onboard.
Regarding U1 and the SELADC 3 way jumper, both can be used (not in the same time but as an option) for the same function, switching ADC input between Voltage and Current measurement.
U1 is a SPDT analog switch IC, you can use there a low ON-state resistance one with the break-before-make feature, like TS5A3159.
Few working examples:
- U1 usage - do autoswitching between Voltage and Current measurements using internal ADC .
- 3 pin SELADC :
- manual select Voltage/Current cource for internal ADC
- choose to connect one source to the internal ADC by jumper and also can go with a second jumper wire to the high precision onboard ADC for example.
The schematics on my blog are accurate but might not include all these functions as quite a few versions released. Will do my best to keep it update (and insanely ugly, lol) but been busy as hell with a lot of things lately.
Happy breadboarding,
TJ.
PS: apparently I am wasting my time posting all these stuff but you know what: I really enjoy it.