This version (15 Jun 2022 14:46) was approved by Alexandru Tachici.

Open Alliance TC6-10BASE-T1x MAC-PHY Serial Interface

Supported Devices

Supported Boards


The IEEE 802.3cg project defines two 10 Mbit/s PHYs operating over a single pair of conductors. The 10BASE-T1L (Clause 146) is a long reach PHY supporting full duplex point-to-point operation over 1 km of single balanced pair of conductors. The 10BASE-T1S (Clause 147) is a short reach PHY supporting full / half duplex point-to-point operation over 15 m of single balanced pair of conductors, or half duplex multidrop bus operation over 25 m of single balanced pair of conductors.

Furthermore, the IEEE 802.3cg project defines the new Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (Clause 148) meant to provide improved determinism to the CSMA/CD media access method. PLCA works in conjunction with the 10BASE-T1S PHY operating in multidrop mode.

The aforementioned PHYs are intended to cover the low-speed / low-cost applications in industrial and automotive environment. The large number of pins (16) required by the MII interface, which is specified by the IEEE 802.3 in Clause 22, is one of the major cost factors that need to be addressed to fulfil this objective.

The MAC-PHY solution integrates an IEEE Clause 4 MAC and a 10BASE-T1x PHY exposing a low pin count Serial Peripheral Interface (SPI) to the host microcontroller. This also enables the addition of Ethernet functionality to existing low-end microcontrollers which do not integrate a MAC controller.

Source Code



Enabling Linux driver support

Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)

  1. Hit the search button (typically the slash “/” key)
  2. Type open_alliance, then hit Enter; if nothing shows up, the driver is not available in your kernel tree, please use the ADI linux tree
  3. Press 1 (the key), then hit Enter
  4. You should see the location + dependencies for enabling the driver
The Open Alliance SPI protocol is used on 10BASE-T1x                                                                                                                                              
MACPHY Serial Interface for communication                                                                                                                                                          
with the host controller.
Say Y to include support for the OPEN_ALLIANCE.                                                                                                                                                    
To compile this driver as a module, choose M here: the module                                                                                                                                      
will be called dnet.                                                                                                                                                                               

Symbol: OPEN_ALLIANCE [=y]                                                                                                                                                                         
Type  : tristate                                                                                                                                                                                   
Defined at drivers/net/ethernet/Kconfig:147                                                                                                                                                        
    Prompt: Open Alliance 10BASE-T1x support.                                                                                                                                                        
    Depends on: NETDEVICES [=y] && ETHERNET [=y] && SPI [=y]                                                                                                                                         
        -> Device Drivers                                                                                                                                                                              
            -> Network device support (NETDEVICES [=y])                                                                                                                                                  
                -> Ethernet driver support (ETHERNET [=y])                                                                                                                                                 
    Selects: CRC8 [=y]

Driver testing

This requires that another 10BASE-T1L PHY be connected to the other end of the network cable, or that a media converter be used to convert to normal twisted-pair ethernet that standard ethernet cables use.

ADIN1110 communicates with the host via SPI. For 10 Mbps bandwidth, SPI frequency needs to be around 23 MHz. Lower SPI frequencies are supported but will result in a lower bandwidth. At 1 MHz the MAC will provide aprox. 0.4 Mbps of bandwidth.

Connect to host the SCLK, CS_N, SDI, SDO and INT_N. (The INT_N is mandatory, see DT bindings). RX frames and sent TX frames are signaled to the host by INT_N IRQ pin.

Device Tree

ADIN1110 probes via devicetree.

ethernet@0 {
	compatible = "adi,adin1110";
        /* SPI CS number */
        reg = <0>;

        /* will need 13.5 MHz for 10 Mbps, lower speeds will result in lower bandwidth */
	spi-max-frequency = <13500000>;

        /* Enables Open Alliance Mode */        

        /* optional, will check all control read/writes over SPI */

	#address-cells = <1>;
	#size-cells = <0>;

        /* an IRQ is required, INT_N pin is configured to signal RX/TX frames */
	interrupt-parent = <&gpio>;
	interrupts = <25 2>;

	mac-address = [ CA 2F B7 10 23 63 ];

	phy@0 {
		compatible = "ethernet-phy-id0283.bc91";
		reg = <0x0>;


This tool will display the general status of the available network interfaces. If they’ve obtained an IP address, RX packets/errors/dropped/etc, TX packets/errors/dropped/etc, MAC address, etc.

Typically, if both TX & RX values are incremented, it means that it is working. Also note that there are error counters; if only the TX/RX counters increment, something may be wrong with the network connection. Check error/dropped counters too.

root@analog:~# ifconfig eth1
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 fe80::c82f:b7ff:fe10:2363  prefixlen 64  scopeid 0x20<link>
        ether ca:2f:b7:10:23:63  txqueuelen 1000  (Ethernet)
        RX packets 132  bytes 8548 (8.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 79  bytes 9943 (9.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 55


This tool queries the MAC & PHY via the MAC driver. The MAC driver also allows access to the PHY registers. ethtool can be used to show & override link settings and other parameters for the MAC & PHY.

Links for the tool:

Some features of ethtool described here are available in newer versions of ethtool. If some of them don't work, consider upgrading or getting a newer version

Example: Seeing MAC & PHY info

Settings for eth1:
	Supported ports: [ TP MII ]
	Supported link modes:   10baseT/Full 
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Full 
	Advertised pause frame use: No
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Link partner advertised link modes:  10baseT/Full 
	Link partner advertised pause frame use: No
	Link partner advertised auto-negotiation: Yes
	Link partner advertised FEC modes: Not reported
	Speed: 10Mb/s
	Duplex: Full
	Port: MII
	Transceiver: internal
	Auto-negotiation: on
	Link detected: yes

Open Alliance also exposes Chunk level statistics:

root@analog:~/ethtool-5.15# ethtool -S adin2111-0-p0
NIC statistics:
     RX valid data chunks received: 362
     TX chunks sent: 1440
     RX end valid chunks received: 61
     RX chunks to frames: 362
     OA chunks transfered: 1802
resources/tools-software/linux-drivers/net-mac-phy/open_alliance.txt · Last modified: 15 Jun 2022 14:45 by Alexandru Tachici