TimeHAT I226 NIC with PPS In/Out for RPi5
Open-source Raspberry Pi 5 PCIe HAT with Intel I226 2.5G Ethernet NIC, dual SMA connectors for 1PPS input/output, built-in TCXO, and M.2 slot for GNSS modules. Ideal for PTP grandmaster clocks.
$200.00
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Specifications
Components
2.5 Gbps PCIe Ethernet controller with hardware IEEE 1588 PTP timestamping, TSN support, and four software-defined pins (SDP0-SDP3) for precision timing I/O.
Temperature-compensated crystal oscillator operating at 33.25 MHz with ±280 ppb frequency stability across the operating temperature range, providing precision clock reference and holdover capability.
Two SMA coaxial connectors for 1PPS timing signals — SDP0 for PPS output (aligned to PTP clock) and SDP1 for PPS input from external reference sources.
Spare U.FL coaxial connector providing unbuffered access to SDP3 for additional timing signal routing.
OCP-compliant M.2 2242 expansion slot for GNSS timing modules (e.g., u-blox NEO-M9N or ZED-F9T) with UART connection to Pi and 1PPS connected to I226 SDP2.
Bus Interfaces
The TimeHAT I226 is a precision timing HAT designed for the Raspberry Pi 5 that combines a high-performance Intel I226-V 2.5 Gigabit Ethernet controller with dedicated timing I/O. By connecting via the Pi 5's PCIe interface through a 16-pin FPC ribbon cable, it delivers full 2.5 Gbps line-rate networking with hardware IEEE 1588 PTP timestamping — making it capable of serving as a PTP grandmaster clock or high-accuracy PTP client right out of the box.
Two SMA connectors provide direct access to 1PPS (one pulse per second) signals: SDP0 outputs a PPS signal aligned to the PTP clock, while SDP1 accepts an external PPS reference from GPS receivers or other timing sources. A spare U.FL connector (SDP3) offers an additional unbuffered timing signal path. The onboard ECS TXO53-S3 temperature-compensated crystal oscillator (TCXO) delivers ±280 ppb frequency stability, ensuring reliable clock holdover performance when the external reference is temporarily lost.
The board includes an OCP-compliant M.2 2242 slot for adding GNSS timing modules such as the u-blox NEO-M9N or ZED-F9T. When a GNSS module is installed, its 1PPS output connects directly to the I226's SDP2 input, enabling automatic clock discipline from satellite time. The GNSS module communicates with the Raspberry Pi via UART, fully supported by gpsd and the ts2phc tool from the linuxptp suite. This combination creates a complete, self-contained GNSS-disciplined PTP grandmaster clock in a compact HAT form factor.
The TimeHAT is an open-source hardware project under the CC BY-NC 4.0 license, developed as part of the Time Appliances Project. A patched Linux igc driver (DKMS module) is provided on GitHub to address PPS edge detection and alignment issues in the stock kernel driver, supporting kernel versions 6.6.x through 6.12.x.
Use Cases
8Precision Timing
Precision time synchronization using PTP, GNSS, and atomic clock references for nanosecond-accurate timekeeping.
PTP Grandmaster Clock
Build a PTP (IEEE 1588) grandmaster clock that distributes precise time to network clients.
GNSS Time Server
GNSS-disciplined time server using satellite-derived PPS for sub-microsecond network time distribution.
Network Time Synchronization
Synchronizing clocks across network devices using NTP, PTP, or other time distribution protocols.
Wired Networking
Build reliable wired Ethernet-connected IoT nodes or edge computing devices.
Home Lab Networking
Networking equipment for home lab environments including high-speed NICs, switches, and time servers.
Edge Computing
Processing sensor data locally at the edge before transmitting to cloud for reduced latency.
IoT Gateway
Acting as a local IoT gateway that aggregates data from sensors, runs MQTT broker, Node-RED, or Home Assistant, and bridges to the cloud.
Resources
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