I am using the Sparkfun GNSS Timing Breakout circuit with the ZED-F9T module. I know that it can be powered with USB-C or Qwiic pins, but after configuring the module I would instead like to power it with power and ground wires sending in 3.3V from a regulated battery source. Is this possible for this device and how might I make this modification?I believed this might somehow be possible via the “MEAS” jumper input but I am unsure.
You could just modify a qwiic cable wired directly to the battery and power via qwiic, or like you mentioned you could try soldering to the MEAS jumper pad https://cdn.sparkfun.com/assets/6/c/2/5/b/SparkFun_GNSS_Timing-ZED-F9T_Schematic.pdf
Hi @izsneha ,
Please be aware that the MEAS jumper is connected directly to the USB-C VBUS power. This is normally 5V. It is also “upstream” of the 3.3V regulator. It feeds the 3.3V regulator U5 (AP2112K):
To use MEAS as a voltage input, you must open the jumper on the back of the board:
Then feed in a voltage of >= 3.6V ( and <= 5.5V) so the regulator can regulate it to 3.3V. The pad next to the PWR LED feeds the regulator:
If you feed in 3.3V here, the regulator will not work correctly. The ZED will receive approximately 3.0V and will probably not work correctly.
If you want to power the board from another regulated 3.3V supply, the easiest way is to use one of the 3.3V breakout pads. But you can also use the Qwiic 3.3V pin if you want to.
I hope this helps,
Paul