Raspberry Pi CM4/CM5 Carrier Board Rev2

A compact six-layer carrier board for the Raspberry Pi Compute Module 4, Compute Module 5 and compatible modules. Rev2 retains the 120 mm × 40 mm form factor while improving CM4 compatibility and adding an I²S connector and two underside expansion-board interfaces.

What's New in Rev2

• M.2 interface revised to support CM4, CM5 and compatible compute modules
• PWM fan control revised to operate correctly with CM4 and compatible modules
• I²S JST connector added to the main board
• Two 50-pin Hirose connectors added on the underside for a companion expansion board

On the previous revision, the M.2 interface was limited to CM5, while CM4 and compatible modules could not use the socket. PWM fan control was also unavailable with those modules, causing the fan to run continuously at full speed. Rev2 corrects both limitations.

Key Features

• Raspberry Pi Compute Module 4 and Compute Module 5 support
• Support for compatible compute modules using the same connector format
• Two 100-pin Hirose compute-module connectors
• Six-layer PCB
• 120 mm × 40 mm form factor
• USB-C data and 5 V at up to 3 A power input
• USB-C CC pull-down configuration
• Gigabit Ethernet MagJack
• 25 W PoE powered-device input
• Jumper-selectable USB-C or PoE power source
• M.2 M-Key socket supporting 2230, 2242 and 2260 modules
• microSD socket for Compute Module Lite variants
• UART, I²C, I²S and PWM fan JST connectors
• PWR and ACT indicator LEDs
• Two underside 50-pin Hirose expansion connectors

Expansion Interface

Rev2 introduces two 50-pin board-to-board connectors on the underside. These expose signals for a planned expansion board featuring:

• HDMI output
• Two CSI camera connectors

Power

The board can be powered through either:

• USB-C at 5 V, up to 3 A
• 25 W Power over Ethernet

The active power source is selected using the onboard jumper connector.

Repository Contents

This repository contains the KiCad project files, custom symbol library, footprint library and associated 3D models for the carrier board.

Status

The main carrier board design is complete. The companion HDMI and CSI expansion board is planned separately.

License

This hardware design is licensed under the Apache License 2.0.

Author

Designed by Asad Imran.