5/26/2025 Announcement: 2.5G ETHERNET, TCXO, 1PPS INPUT, 1PPS OUTPUT FUNCTIONALITY ONLY. PLEASE NOTE V5 BOARDS DO NOT SUPPORT M.2 GNSS SLOT.

Due to this, I will be discounting V5 design by $60.

If you want to make a grandmaster setup with V5, I recommend using https://www.nettimelogic.com/shop.php#!/USB-to-RCB-M-2-PMOD/p/690205597 with the M.2 GNSS and use a cable to connect the 1PPS from the GPS to the TimeHAT SMA

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Raspberry Pi 5 PCIe HAT with I226 NIC

The Raspberry Pi 5 PCIe HAT is designed to bring precision timing and advanced network functionality to the Raspberry Pi 5 platform. Leveraging the PCIe interface via an FPC connection, this HAT expands the Pi’s capabilities by integrating a high-performance I226 Ethernet NIC, precise timing inputs and outputs via SMA connectors It’s a powerful tool for building small form-factor PTP (Precision Time Protocol) clients, ideal for time-sensitive networking applications.

Included in box

A. TimeHAT

B. 40 pin spacer

C. 16-pin FPC PCIe cable

D. Spacers, nuts, and screws for mounting to RPI5

Github Repo

For Discussions and issues or information not found in the instructions below, please visit our Github: https://github.com/Time-Appliances-Project/Products

Jeff Geerling also has a Github repo that relates to this product: https://github.com/geerlingguy/time-pi

Key Features:

I226 Ethernet NIC

The HAT features an Intel I226 NIC connected to the Raspberry Pi 5 over the PCIe interface, delivering fast, reliable Ethernet connectivity. This makes it suitable for applications requiring high-speed networking combined with precise timing.

Precision Timing via SMA Ports

The HAT includes two SMA connectors for timing signal input and output:

SMA Input (SDP1 on I226): Allows the HAT to receive a 1PPS (one pulse per second) signal, which can be used as a reference to discipline the NIC’s internal clock.

SMA Output (SDP0 on I226): Provides a 1PPS output signal from the NIC, which can be used to measure precise time intervals or synchronize external equipment.

Spare U.FL (SDP3 on I226): A raw unbuffered connection from SDP3 on the I225 goes to a spare U.FL, can be used as input or output. WARNING: This is also a strapping pin on the I226. If you have this connected when the card boots up, it may make the Ethernet connectivity not work.

These timing features enable the HAT to act as either a PTP client or a PTP grandmaster, providing precise time synchronization for your network.

Built-in TCXO

For enhanced timing stability, the HAT includes a high-precision Temperature-Compensated Crystal Oscillator (TCXO).

Improved Holdover Performance: The TCXO ensures that the NIC’s timing remains stable even during network loss.

Improved stability: Using a TCXO backed NIC, you can adjust the disciplining parameters to reduce timing jitter recovered over PTP

TCXO Used: https://www.digikey.com/en/products/detail/ecs-inc/ECS-TXO53-S3-33-250-BN-TR/17802084 +/- 280ppb stability across temperature

Applications

This HAT is designed for a variety of precision timing and networking applications:

PTP Client: Use the HAT to synchronize with sub-microsecond accuracy.

1PPS Signal Measurement: Measure and verify 1PPS signals for precise timekeeping in your system.

Edge Networking: Deploy the HAT in edge computing environments where precise timing is crucial.

Why This HAT is Special

The Raspberry Pi 5 PCIe HAT combines high-speed networking with advanced timing features in a compact, easy-to-deploy form factor. It allows makers, hobbyists, and professionals to build small yet powerful PTP solutions using the versatile Raspberry Pi 5 ecosystem. The HAT's ability to act as both a PTP client, combined with a TCXO, makes it a unique offering in the world of precision timing hardware.

What This Enables

Home Labs: Create a PTP client networkfor your home lab with ease.

IoT Gateways: Build precise IoT gateways that require synchronized time across devices.

Research and Development: Ideal for experimenting with PTP and timing protocols in various network configurations.

Whether you’re building a precise timekeeping device or exploring the world of networked time protocols, the Raspberry Pi 5 PCIe HAT is your gateway to advanced timing applications. Designed to integrate seamlessly with the Raspberry Pi 5, this HAT empowers you to bring professional-grade timing and networking to your projects.

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Usage steps

Pre-setup steps

A. Install linuxptp

sudo apt install linuxptp

B. Download testptp

cd ~ ; mkdir testptp; cd testptp

wget https://raw.githubusercontent.com/torvalds/linux/refs/heads/master/tools/testing/selftests/ptp/testptp.c

wget https://raw.githubusercontent.com/torvalds/linux/refs/heads/master/include/uapi/linux/ptp_clock.h

sudo cp ptp_clock.h /usr/include/linux/ptp_clock.h

C. Compile testptp

gcc -Wall -lrt testptp.c -o testptp

D. Install testptp

sudo cp testptp /usr/bin/

E. Verify testptp works

sudo testptp -d /dev/ptp0 -l

Should see

pi@raspberrypi:~/testptp $ sudo testptp -d /dev/ptp0 -l

name SDP0 index 0 func 0 chan 0

name SDP1 index 1 func 0 chan 0

name SDP2 index 2 func 0 chan 0

name SDP3 index 3 func 0 chan 0

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Configure 1PPS Output

1. Setup SDP0 (SMA1, closest to HAT header) as periodic output

sudo testptp -d /dev/ptp0 -L0,2

sudo testptp -d /dev/ptp0 -p 1000000000

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Read 1PPS SMA Input

A. Setup SDP1 (SMA2 , furthest from HAT header) as timestamp input

sudo testptp -d /dev/ptp0 -L1,1

B. Read timestamps, use -1 to read forever and ctrl+C to stop, using 5 here as demo. Note: I226 driver passes both edges to Linux, so both rising and falling edges will be listed. A fix for this is listed below, requires patching and building kernel

sudo testptp -d /dev/ptp0 -e 5

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Discipline to 1PPS SMA Input

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Fix 1PPS input to only use rising edge, New Method, much easier

Procedure documented on Github: https://github.com/Time-Appliances-Project/Products/tree/main/TimeHAT