This HAT is pretty simple but its worth going thru what pins are used for what!

The Ultimate GPS uses the following GPIO pins: TXD, RXD, #4 and EEDATA/EECLK

Serial Console Pins

The Raspberry Pi has only one serial port, and you do need serial to chat to a GPS so we will take over the RXD and TXD pins.


GPS's can output a 'pulse per second' for synchronizing the time. We have a breakout for this and a closed jumper that connects it to GPIO#4 - if you do not need PPS and want to  use #4 for something else, just cut the little connection on the PPS PCB line.


EEDATA/EECLK are connected to a 24C32 EEPROM that contains the name and maker of this HAT (it's not used by the Pi Kernel just yet)

This guide was first published on Dec 26, 2014. It was last updated on Mar 08, 2024.

This page (Pinouts) was last updated on Mar 08, 2024.

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