Hey, Mark, can I please have some more EE help? smile

I'm confused about something on the WT32i datasheet.

I'm going by this document:
https://www.silabs.com/documents/login/data-sheets/WT32i-DataSheet.pdf

My current goal is to try powering the chip entirely from the already-regulated 3v line coming off the Arduino. I'll cut the CHG_ENA jumper on the Betz board and/or simply not supply any voltage to the Betz 5vin pin (both will accomplish the same thing based on the Betz schematic).

It looks like, if I'm going to power the chip with pure 3v and not use the BATT or CHG lines, then that is theoretically supposed to be supported on the WT32i datasheet since there's a sentence saying so.

It says in section 6, "The module can be powered from a single 3.3 V supply provided that VDD_CHG is floating." Great, that's what I'm planning to do: Supply it with a single 3v supply and completely disconnect VDD_CHG.

I think I might need to do this:

- 3v into VDD_IO, definitely.
- (some unspecified amount of voltage) into VREG_ENA? (Not sure the dox aren't clear.) Can that be the same 3v too?
- Not sure what to do with VDD_BAT - I think I should supply 3v to that one too?

I'm pretty sure I need all of the above because the serial communications are driven off of VDD_IO but the radio is driven off of VDD_BAT which powers an internal voltage regulator that gets activated by power on VREG_ENA. That's great, but there is nothing in the datasheet that indicates what voltage is expected to be applied to VREG_ENA and what its limits are.

However, there's this confusion. It has a warning which says:

"Figure 10 shows an example how to arrange power control when on/off button is not implemented. VREG_ENA pin must not be connected to VDD_IO because leakage from VDD_BAT to VDD_IO will prevent VREG_ENA to fall low enough to turn off the internal regulators."

But... Figure 10 is in fact illustrating an On/Off control. The sentence says "When on/off button is not implemented", but then Figure 10 has a part on the drawing that says "On/Off Control". That's opposite of what the above sentence says. True, it's in a different spot than on Figure 9 (Figure 9 shows a temporary pushbutton), but it's still an "on/off control" of some kind. In fact the title of Figure 10 is "Figure 10: Correct and wrong connection for the power on/off control". So the datasheet is contradicting itself and now I don't know what to do.

What I want to do is take the 3v pin from the Arduino and supply 3v to the WT32i from that pin. I don't think I should need to go through yet another voltage regulator to supply power to VREG_ENA. And looking at Figure 8 seems to indicate that there's a voltage regulator inside the chip, which is connected to the OUT of the battery charger. That makes sense that leakage from that would cause problems there in the ENA pin of that internal regulator. But the instructions are weird, they say "leakage from VDD_BAT to VDD_IO will prevent VREG_ENA to fall low enough to turn off the internal regulators" but that's the opposite of what I want: I want the internal regulator ON all the time so that the chip never turns off.

Is it simply that I need to supply 3v to all three of VDD_BAT, VREG_ENA, and VDD_IO, and since I'm powering it up 100 percent of the time, ignore that warning in the datasheet about not tying to tie VREG_ENA to VDD_IO?

Can you tell based on the data sheet, specifically, figures 8, 9, and 10?

Thanks!
_________________________
Tony Fabris