Grounding Issue with INA?

SFUSatClub / obc-hardware

PCB design for the initial prototype of OBC hardware, to interface with LaunchPad.

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Closed richarthurs closed 6 years ago

richarthurs commented 6 years ago

With the following jumpers connected:

the external UART is wonky. If you ground the external UART to the 104 connector, it shorts? If you ground it to the GND jumper, nothing changes.

With the two power jumpers connected as mentioned above but INA_EN open, everything is ok.

richarthurs commented 6 years ago

Nope, turned out to be a config issue where the reverse polarity FET gate was not being driven, causing ground to disconnect.

On 0.4:

3v3 to INA_IN, GND to 104 gnd pin. Must jump 3v3 pin (on the INA source control header) and 5V on the 104 connector to turn on the 5V reverse polarity FET and have a full loop.
or power through the 5V in on the 104 connector