Raspberry Pi gets 10BASE-T1S/T1L Single Pair Ethernet (SPE) HAT+ board

Germany-based Brechel Electronic has launched two new Single Pair Ethernet (SPE) expansion boards for Raspberry Pi platforms: the BE-IIS-HPP-T1S and the BE-IIS-HPP-T1L. Designed for technology evaluation, industrial network prototyping, and educational laboratory use, these boards add 10 Mbit/s Ethernet communication over a single twisted pair to standard Raspberry Pi SBCs.

The BE-IIS-HPP-T1S is based on the Microchip LAN8651 10BASE-T1S MAC-PHY and supports IEEE 802.3cg Single Pair Ethernet over multidrop networks with up to 8 nodes, enabling distances up to 25 meters on a shared bus. For longer-reach point-to-point links, the company offers the BE-IIS-HPP-T1L, built around Analog Devices ADIN1110 MAC-PHY. Both boards are part of the BE-IIS HAT++ ecosystem, which allows multiple industrial communication HATs to be stacked on a single Raspberry Pi without running into SPI or GPIO resource conflicts.

Brechel Electronic 10BASE-T1L and 10BASE-T1S specifications:

• Compatibility – Raspberry Pi HAT+ compliant
  • T1L – Supports Pi 3, 4, 5, and Zero 2 W
  • T1S – Supports Pi 2, 3, 4, 5, Zero, and Zero 2 W
• MAC-PHY
  • T1L – Analog Devices ADIN1110
  • T1S – Microchip Technology LAN8651
• Networking
  • Topology – IEEE 802.3cg
    • T1L – 10BASE-T1L long-reach point-to-point link
    • T1S – 10BASE-T1S multidrop supporting at least 8 nodes over up to 25 meters
  • Galvanic Isolation
    • T1L – via transformer coupling with 2250 V DC / 60s rating
    • T1S – via capacitive coupling with a minimum 5 mm clearance
  • Protocol
    • T1L – Transmit amplitude of 1.0 Vp-p or 2.4 Vp-p via autonegotiation
    • T1S – CSMA/CD operation support with PLCA (Physical Layer Collision Avoidance)
  • 10 Mbps data rate over a single twisted pair
  • 3.5mm terminal block or PCB headers
    • T1L – Single connection port
    • T1S – Dual multidrop connector positions (J4000, J4001) in parallel for daisy-chaining
• Host interfaces
  • 40-pin Raspberry Pi header; high-speed SPI interface (SPI0.0, SPI0.1, and SPI0.2 supported)
  • Full support for the BE-IIS HAT++ stacking ecosystem (allows stacking up to 5 different HATs or up to 3 of the same HAT type per system)
• Misc
  • Push-button for persistent Instance ID selection
  • Configuration jumper for bus termination
  • 3x Board Interconnect Options (I: Default, II: Stacking Option II, III: Stacking Option III)
  • Management IC for “Detect & Stack” functionality with persistent configuration
  • 7x on-board indicator LEDs (including SPI ACT, LINK_ST, and general status LEDs)
• Power
  • Integrated 5V main supply (draws ~35mA at 5V, ~9mA at 3.3V)
  • Supports optional Power over Single Pair Ethernet (PoSPE) via an add-on HAT; up to 1 A and input voltages from 9 V to 33 V
• Dimensions – 65 mm × 56 mm Raspberry Pi HAT+ from factor (15 mm recommended stack height)

Looking at both the boards and their specification hardware-wise, they are very similar, but the BE-IIS-HPP-T1L variant swaps the Microchip MAC-PHY for the Analog Devices ADIN1110. It is specifically optimized for longer range 10BASE-T1L point-to-point links, while maintaining the galvanic isolation and HAT+ compliance found on the T1S model.

Both HATs are supported by the BE-IIS installer, which automatically installs the required Linux drivers, Device Tree overlays, and system services on Raspberry Pi OS. After installation, the boards appear as standard Linux network interfaces, allowing configuration and testing with common networking tools such as ethtool. The company provides open-source software and documentation on GitHub.

Other interesting maker-focused Single Pair Ethernet (SPE) boards include the Arduino UNO SPE Shield, also based on the Microchip LAN8651 for 10BASE-T1S multidrop networking, and SparkFun’s MicroMod Single Pair Ethernet kit, which leverages the Analog Devices ADIN1110 for long-range 10BASE-T1L point-to-point communication. Brechel Electronic’s new HATs bring 10BASE-T1S and 10BASE-T1L Single Pair Ethernet support to Raspberry Pi, along with galvanically isolated interfaces and HAT stacking support.

The Raspberry Pi 10BASE-T1S and 10BASE-T1L HATs can be purchased from DigiKey or on the company’s Tindie store. The 10BASE-T1S version sells for €95.54 ($115), while the 10BASE-T1L model is priced at €113.07 ($135), with both products shipping from Germany. More information about the boards can be found on their respective product pages.

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