Taking this one as an example, do you mean picking up either 3V3 or 5v and then: Is this for feeding the I2C switch? Also, do I need to connect the LV (no number) to anywhere on our BPI?
BPI -------------- Level Shifter ---------- CH340 (or others)
RX --------------- LV1 <--> HV1 ---------- TX
TX --------------- LV2 <--> HV2 ---------- RX
GND ------------ GND <--> GND ---------- GND
------------------- HV(no number) ---------- 5v or 3V3 pin
HV an LV are used to put the corresponding voltages on the pull-up resistors and ‘feeding’ the mosfet See the schematic I send earlier.
You can choose just 1 source for 3.3V because HV and LV are equal Also be sure not to connect the 3.3V supply from the uart to the 3.3V supply of the R3.
This probably is the schematic. A very cheap and dirty way to get 3.3v. In your picture you can see the 2 orange diodes. So after seeing this I would suggest using 3.3V from R3 gpio terminal
Oh, so instead of feeding the I2C with the 3v3 coming from the UART VCC output, I’d rather power it up with a R3 3.3v from it’s GPIO, right?
I would try to find an uart that has a stable 3.3V regulator if the uart is fed from 3.3V.
Or cut away the diodes and feed all 3.3V from R3
Noticed the jumper is in the wrong spot, do not put it there it should be mirrored on the other side…
Guess this is a picture from internet, not the one from you?
Yes, mine is on VCC+3V3
