Qwiic pHAT Extension for Raspberry Pi 400 Hookup Guide
bboyho, 
Elias The Sparkiest 
Hardware Overview
2x20 Raspberry Pi Header
The Qwiic pHAT extension connects to the Raspberry Pi 400's 2x20 port via the right angle header.
The Raspberry Pi 400's horizontal headers are rerouted and extends out to the vertical headers at the top of the board. Each pin includes a label with their associated pin function.
Qwiic Connectors
The Qwiic pHAT extension includes Qwiic connectors on both sides of the board.
Mounting Holes
There are 10 mounting holes on the board. Below is the board highlighted for boards designed with the Pi Zero footprint. You can add standoffs to the mounting holes where the arrows are pointing.
For boards designed with the Raspberry Pi footprint, you can add standoffs to the mounting holes where the arrows are pointing.
For Qwiic-enabled devices utilizing the standard 1.0"x1.0" sized boards, you can add two standoffs for each Qwiic-enabled device where the arrows are pointing.
Board Dimensions
The board is about 65mm x 78.42mm (~2.55in x ~3.08in).
By adding two large silicone bumpers under the board for stability, the height comes to about ~21.32mm (~0.84in) between the header pin and the bottom of the Silicon bumper.