Hi. I bought some of the Pimorni BME280 breakout boards a while ago, and have recently started trying to use them. They seem to work fine when I connect using the PCB pads (where the header can be soldered), but not when I use the QWIIC connector.
On investigation, it seems that the GND wire from the QWIIC connector is not connected to the GND wire on the PCB pads (though the +V, SDA and SCL wires are all connected fine).
Is this a known issue with some (older) batches of this board?
OK just after posting I found this post with schematics, which suggests that measuring continuity between the GND on the QWIIC connector and the PCB pads may be affected by the reverse polarity protection:
I’ll investigate that angle and see whether that might explain some of what I’m seeing…
Digital ground is always a common ground. But the “GND” of the pcb-pad is actually not a GND, but connected to a mosfet. That is why you can’t measure anything. Add 5V to the 5V pin and you should see connectivity.
Ah, OK, I better clarify my above post. I haven’t had any issues using the QWICC connector, or the solder pads. From time to time I have actually used both. I have soldered (stacked) two breakouts via the solder tabs and a male header. Then used a QWICC cable to plug them into a Pi of Pico.
I’m not sure if I have ever put a meter on and measured that ground from the pad to the QWICC though?