Running dual QWIIC GPS modules

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Titan
Posts: 3
Joined: Tue Jul 31, 2018 1:34 pm

Running dual QWIIC GPS modules

Post by Titan » Thu Sep 06, 2018 2:08 pm

Hi all! I am playing with the QWIIC GPS module and the i2C breakout board from SF. I want to be able to read from both GPS modules, but I can't seem to find out how to use I2C addressing with the example sketches provided. I also have no way of knowing the I2C address of each QWIIC GPA module. I have run some of the examples and I'm able to get GPS data from a single QWIIC, but can someone point me in the right direction for pulling data from 2 of them. Thanks!!

Valen
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Posts: 1743
Joined: Wed Dec 22, 2010 2:05 am

Re: Running dual QWIIC GPS modules

Post by Valen » Sat Sep 15, 2018 6:11 am

The schematic mentions the unshifted I2C adress that the GPS module would respond to. When writing or reading to it you need to shift a direction bit in front of it (most significant bit). It's probably also mentioned in the Titan 1 GPS datasheet. (not sure, only skimmed it) It does not seem to have a way of making it respond to different adresses through pin selection. So multiple modules wil not cooperate on the same I2C bus. An I2C Bus multiplexer chip would be needed. Something like this: https://learn.adafruit.com/adafruit-tca ... t/overview

Valen
Support Volunteer
Posts: 1743
Joined: Wed Dec 22, 2010 2:05 am

Re: Running dual QWIIC GPS modules

Post by Valen » Sat Sep 15, 2018 6:18 am

I see that Sparkfun has a similar I2C bus multiplexer: https://www.sparkfun.com/products/14685

Is this the one that you mentioned using?

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