How to supply power to and connections between GSP-RTK breakout and Teensy4.0

Components & Accessories Power
1

I am working on a rover project where I have a Sparkfun GSP-RTK-SMA breakout. I am going to use a Teensy4.0 to process the information from the GPS. I will also have a SIK Telemetry Radio and a qwiic OLED display. I see a potential problem to supply power and make I2C connections.

I have a 12V battery with a 12v to 5v converter. My plan is to connect the 5v supply to the GPS board, the Teensy board, and the radio. I plan to use I2C to connect the Teensy to the GPS board and the OLED display used the qwiic connectors. I have a qwiic adapter board that I’ll wire up to the Teensy.

My question is related to the 3.3v supplies on the GPS board and the Teensy board being connected through the qwiic connectors. Both the Teensy and GSP boards have 5v to 3.3v converters. If I connect them together with a qwiic cable could it cause issues that the two 3.3v supplies are tied together?

If this is an issue are there recommendations on the best way to handle this?

Thanks for any assistance you can provide.

2

If it were me, I’d connect a qwiic cable to 3.3v, SDA, SCL and GND on the teensy and connect the GPS and display via qwiic. The qwiic cables will provide the display and GPS with the needed 3.3 volt power from the teensy as well as I2C data.

Just supply the teensy with 5 volt power and it will handle powering everything else for you.

3

My concern here is that the Teensy can supply 250mA max on 3.3v. The gps can take up to 130mA, plus the OLED display is up to 20mA. While that is under 250, it is a limitation for future additions.

One possibility that I considered is to not use the qwiic connectors on the gps board, but to connect I2C using wires to connect SCL and SDA between teensy and gps, but not the 3.3v. Then use qwiic to connect teensy to the OLED display (and future additions).