Unfortunately, not all good. In order for things to work at all, I have to supply the Betz board voltage from a USB cable connected to its USB connector instead of from the 5v pin from my Pololu power supply.

I'm not understanding why things are different between those two things. The USB tends to supply 4.8v and the Pololu supplies much closer to exactly 5v, but I don't see why those two things are so different as to cause a problem.

I'm happy to try different resistor values. Any ideas?

Looking at the Betz circuit board and the WT32i datasheet, my brain breaks because it goes round in circles. It looks to me like I'm supplying 5v to the VDD_CHG pin which is, I think (not sure) supposed to be the input voltage for the battery charger. Then the VDD_IO is supposed to receive about 2-3v for its main power for serial and bluetooth. I think this happens via a built-in voltage regulator which puts out some unspecified amount of voltage on the pin VDD_BAT which the Betz board does some stuff with.

Betz puts the VDD_BAT output through the SMD-2-pole switch which turns the voltage round and puts it through a little voltage regulator which then is supposed to supply 2.5 volts to VDD_IO.

This voltage only exists because the BT chip itself is putting out the voltage on its VDD_BAT pin and only because that same voltage from VDD_BAT is also looped round and goes back in VREG_ENA which enables the chip's internal voltage regulator so that it can output VDD_BAT so that it can put that voltage back in to VREG_ENA so that it can put out voltage on VDD_BAT so that it .... (sound of head exploding).

In any case, it all sorta kinda works but only if I'm giving it voltage from that USB plug and not from the 5v pin. But what's the difference? there shouldn't be, according to the schematic.

Basically, it's not working right now and I'm not understanding why.