Datasheet

Pinouts
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.
PPS Pin
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.
HAT EEPROM
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)
© Adafruit Industries https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi Page 5 of 18