User’s Guide

The MACPHY USB to T1S bridge is a software driven bridge/media converter project, allowing direct network access to a 10Base-T1S network via USB. The 10Base-T1S connectivity is provided by the Analog Devices AD3306 MACPHY. The microcontroller, including USB connectivity, is provided by the Analog Devices MAX32690 MCU. Features of this project include:

Software controlled USB networking (NCM) - Windows, Linux and Mac compatible
Integrated USB serial console for control and configuration
Non-Volatile memory for persistent settings
Bootloader with USB mass storage for easy reprogramming
Wireshark and EdgeStudio support (via networking)
EdgeStudio support (via USBi)

Getting Started

Installing Device Drivers

The MACPHY USB to T1S comes pre-loaded with the bridge software so it is ready to use out of the box. The USB descriptor features a standard NCM and CDC Serial device classes, and do not require special drivers to be installed on your system and should enumerate automatically when connected.

The device IDs are:

- VID: 0x0456 (Analog Devices)

- PID: 0x1140

Windows

Once installed, the device should appear as an Analog Devices T1S Network Interface in the device manager:

img_devman_ncm

And as a valid network device in the Network Adapters. Note the adapter name (i.e. Ethernet 9) may be different on your machine:

img_win_netadapters

As well as a Generic Serial Port in the device manager. Note the COM number may be different on your machine:

img_devman_serial

Linux

For most standard Linux installations, no additional device drivers are required for us. The project has been tested with out-of-the-box versions of Ubuntu and Raspberry PI OS. When connected to a Linux system, detection of the device can be verified with the command lsusb , looking for the 0456:1140 device VID and PID.

img_lsusb

Further, the device will appear as a network device, visible to tools such as ifconfig , as well as the device itself within /sys/class/net. Note, the device name (i.e eth1) may be different on your machine.

img_ifconfig

The integrated USB serial console will also be present within the /dev/ folder, typically as /dev/ttyACM# or /dev/ttyUSB#

img_ls_serial

Mac OS

USB-NCM and USB serial is natively supported on MacOS, however this project has not yet been tested on MacOS systems.

Network Configuration

The NCM network device will appear as any standard networking adapter for your host computer, and can be configured the same as any other connection. For use as a general network monitor (sniffer) or L2 networking only (e.g. 10Base-T1S), configuring an IP address is not necessary. However, for TCP/IP networking, it is recommended to set a compatible IP address for your network. The process for configuring an IP address is not specific to this device, however here are some helpful links:

Windows - Essential Network Settings and Tasks
Raspberry PI - Network Configuration
Ubuntu - Network Manual
Mac OS -

USB Console Port

The configuration of the device is done through a USB emulated serial port. When connecting to the port, the baud rate and other settings are ignored due to the direct USB connection. There are a variety of tools which can be used to access the console, with just a few listed below. Tool choice is a matter of preference and the functionality should be consistent regardless.

The menu system leverages VT100 style special characters. Ensure the terminal emulation mode of your tool of choice is setup for VT100 for best performance.

Windows
- Putty
- TeraTerm
Linux
- picocom
- minicom
Mac OS
- CoolTerm

Hardware Overview

img_layout

Connectors and Jumpers

P1 - USB

P1 is the USB-C connector which provides 5V power to the board and USB connectivity to the microcontroller providing the USB networking device and serial console.

P8 - T1S

P8 is the connector for joining the T1S network with unshielded, twisted pair wire. The connector is compatible with standard Phoenix Contact 3.81 mm pitch terminals.

P2 - USBi

P9 / P10 - T1S Termination

P9 and P10 provide 50 Ohm termination to the T1S data bus. When operating as the end node (the first or last node) on a bus, install jumpers on P9 and P10 to correctly terminate the bus. When installed as a drop or middle node on a multi-drop bus, leave P9 and P10 open.

LEDs

LED1 - Bootloader / USBi

LED1 is a red LED. When illuminated, it indicates the MCU is currently in the bootloader state, awaiting a new software load. The USB connection will be the bootloader’s mass storage device and normal networking bridge operation will not be active.

This mode also allows the USBi connector to be used for direct SPI interaction with the AD3306 MACPHY for use with EdgeStudio and USBi adapter. The MCU’s SPI peripheral will be in reset, allowing unrestricted access to the SPI signals.

LED2 - T1S Activity

LED2 is a greed LED. Flashing indicates inbound activity on the T1S network interface. Given the functionality of the software is a bridge, the LED indicates inbound activity only to help determine the origin of network traffic.

LED4 - USB Activity

LED4 is a greed LED. Flashing indicates inbound activity on the USB network interface. Given the functionality of the software is a bridge, the LED indicates inbound activity only to help determine the origin of network traffic.

D7 - Mode

D7 is a tri-color LED used to indicate operating mode.

Green - When illuminated green, this indicates the software is operating in bridge mode, allowing bidirectional traffic between the USB network interface and the T1S network
Blue - When illuminated blue, this indicates the software is operating in sniffer mode, allowing the USB network interface to monitor T1S traffic, but not send data onto the T1S network.

Power Good LEDs

In addition, D2 (1.1V), D3 (5V), and D4 (3.3V) are red LEDs providing power good indicators for the on-board power supplies. It is expected these are all illuminated upon USB-C power being applied. These LEDs are not called out in the above figure.

Push Buttons

SW1 - Reset

The reset button is connected directly to the physical reset line(s) of the devices issuing a board-wide reset.

The reset button may be also used to enter the bootloader by pressing the reset button twice, within 500ms of each other. This will enter bootloader mode and allow for reprogramming or USBi operation.

SW2 - BOOT

The BOOT button allows the user to enter the bootloader from the software application. While the bridge software is running, press and hold BOOT for 3 seconds, this will restart the MCU into bootloader/USBi mode without needing to perform a Reset double tap.

SW3 - USER

The USER button allows switching between bridge and sniffer modes in real time during operation. Press and hold USER for 3 seconds to toggle the current operating mode.

Note: The operating mode selected by the USER button is not saved through power cycles. See the Configuration section for information on setting the power up default.

General Operation

Bridge Mode

Bridge mode is the primary operating mode of the system, allowing a host computer to join a 10Base-T1S network via the USB network interface.

It is important to understand that the Bridge should be considered a transparent device similar to a USB to Ethernet or Wifi adapter would be. In other words, the bridge itself is not a node on the network, but rather the USB host is the active network node. As part of the configuration, the bridge has an assignable MAC address. This MAC address is the address of the USB interface of the host.

During operation, the bridge transparently moves incoming frames from USB out T1S, and vice versa, The T1S network is capable of a maximum of 10Mbps, while the USB network interface is capable of supporting more. Through the use of internal buffers, there is some tolerance for USB rates exceeding 10Mbps, however if the host exceeds this rate beyond the capacity of buffering, the frames will be silently dropped by the bridge. The statistics of network traffic, including the number of dropped frames can be seen from the console interface stats command.

This mode is indicated by a green status LED D7. To switch to Bridge mode from sniffer mode, hold down the USER button for 3 seconds until D7 turns green. Bridge mode can be set as the power on default mode via the console interface.

Sniffer Mode

Sniffer mode provides similar functionality to Bridge mode by joining a T1S network via USB, however traffic is restricted to the USB host only receiving T1S bus data, not allowing data to be put on to the bus. The primary use case of this mode is with tools such as Wireshark to allow passive monitoring and inspection of the bus traffic for debugging and characterization.

From a host computer stand point, there is no visible difference between bridge and sniffer modes in how the network interface is added and displayed in the system, as standard USB network interfaces (NCM in this case) do not offer a simplex configuration option. The traffic control preventing USB origin traffic from the T1S bus is done in the bridge software, where USB frames are silently dropped. These dropped frames will not be indicated in the stats display when in sniffer mode.

Depending on the host PC, the system may attempt to send frames over the USB network interface as part of its normal operation (DHCP requests, local network advertising, etc). These frames will be dropped by the bridge, however will be visible in tools such as Wireshark as transmitted traffic. It is recommend to apply a Rx only filter when using Wireshark to get a clear visual of the actual T1S bus.

This mode is indicated by a blue status LED D7. To switch to sniffer mode from bridge mode, hold down the USER button for 3 seconds until D7 turns blue. Sniffer mode can be set as the power on default mode via the console interface.

When sniffer mode is activated, by either power on default, or the USER button, PLCA will automatically be disabled on the AD3306 T1S interface. This prevents any conflicts of PLCA IDs when using the tool on existing networks. When sniffer is not activated, the PLCA settings in the configuration will be utilized.

Bootloader / USBi Mode

In bootloader mode, the main MCU software is not loaded and instead a USB-based drag-and-drop bootloader is running to support program updates. The USB interface will appear as a mass storage device on the host PC. See Re-Programming for additional details on using this mode.

This mode is indicated by a red status LED1. To enter bootloader mode, hold the BOOT button for 3 seconds while in bridge or sniffer mode. This will reset the board into the bootloader. Alternatively, preset the RESET button twice within 500ms to enter the bootloader.

USBi

While in bootloader mode, many of the MAX32690 MCU peripheral interfaces, including the SPI bus to the AD3306 are disabled. This allows use of the P2 USBi to directly utilize the SPI bus to the AD3306 with EdgeStudio. See the EdgeStudio user’s guide for more information on using the USBi interface within the tools.

Console Interface and Configuration

The console interface is provided through a USB virtualized serial port. See USB Console Port for recommendations on terminal tools for your host computer. The terminal is a menu-based system.

On most terminal software, the Up/Down arrow keys can navigate the menu, however some terminal applications do not support the arrows correctly. As an alternative the w (up) and s (down) keys can be used instead.

Menu Navigation:

Up/Down or w/s, Move the selected menu index up or down
Enter - Enter the sub menu or configuration field
ESC - Go back a page

A typical menu will look like the following, with the actively selected row highlighted:

img_mainmenu

When editing configuration values, or other screens which require user input, contextual help will be displayed to indicate the purpose of the field, ranges and other useful information. Below is an example of a configuration screen for the MAC address:

img_mac_edit

Main Tree

For reference, the menu tree is expanded in the diagram below. Detailed descriptions of these blocks are in the paragraphs that follow.

img_menu_tree

Main Menu

Main Menu - System Information

Displays current runtime information on the system:

Version: This is the git hash used to build the running software. Code which has been modified from the commit will be tagged dirty, while releases will be tagged with their git release.
Build Date: The date and time the software was compiled
MAC: The current MAC address assigned to the USB network interface
PLCA: The current state of the PLCA function on the AD3306, its enable status, ID, and number of PLCA nodes
AD3306: Indicates the mode of the AD3306/T1S interface. This should always say Tx/Rx
USB: Indicates the mode of the USB interface. This will say Tx/Rx in bridge mode, and RX Only in sniffer mode.

Version: v1.0.0-rc2
Build Date: 06-17-2026 17:08
MAC: 00:E0:22:33:00:00
PLCA: Enabled, ID: 0, Count: 16
AD3306 (T1S): TX/RX
USB: TX/RX

Main Menu - Network Statistics

Displays the network statics of each interface, including the number of frames that were dropped. Note, the dropped frames do not include any frames intentionally dropped due to being in sniffer mode, only frames dropped due to buffer capacity or other reasons.

When operating in sniffer mode, the USB interface will only display outbound statistics as all inbound frames are dropped automatically.

AD3306 (T1S):
  Outbound: 94, Dropped: 0
  Inbound: 0, Dropped: 0
USB:
  Outbound: 0, Dropped: 0
  Inbound: 94, Dropped: 0

Main Menu - FreeRTOS Usage Information

Displays runtime information for the FreeRTOS system running the bridge software. This is useful for software development and debug, as well as understanding CPU resource utilization when operating under a variety of network conditions.

Uptime: The amount of time the software has been running since the last reboot or power cycles
Heap: The amount of remaining heap space in the FreeRTOS dynamic memory allocator.
- Note: The system uses dynamic allocation at start up, but not during runtime. This value should be fixed following initialization.
Task Information:
- Task: Plaintext task name
- CPU%: Approximate CPU utilization as a percentage of the overall system
- PRI: Task priority. Higher is a higher priority
- S_BASE: Base address in RAM of this task’s stack
- S_MARGIN: The number of bytes remaining in the task’s stack at its highest usage. A watermark of the least amount of stack space available since running.

Uptime: 3844 seconds
FreeRTOS Heap: 5896 / 71680 Bytes Available (8%)

| Task       | CPU% | PRI |   S_BASE   | S_MARGIN |
|============|======|=====|============|==========|
| CDC        |   <1 |   4 | 0x20057138 |    680 B |
| CONFIG     |   <1 |   3 | 0x200575b8 |    532 B |
| IDLE       |   99 |   0 | 0x20015a84 |    472 B |
| Background |   <1 |   1 | 0x20047c70 |   1240 B |
| Logging    |   <1 |   2 | 0x200489a0 |    380 B |
| USBD       |   <1 |   6 | 0x20056b18 |    696 B |
| OASPI_U0   |   <1 |   8 | 0x20056698 |    892 B |
| OASPI0     |   <1 |   7 | 0x20055a18 |   2576 B |

Main Menu - Configuration Menu

Opens the configuration menu.

Main Menu - AD3306 Debug

Opens the AD3306 debug menu.

Configuration Menu

The configuration menu is used to set the power on values for various system settings. Once a setting is changed it will automatically be saved to EEPROM. The settings will be applied at the next power cycle/boot.

This settings are the power on default values only. Changing settings here will NOT impact the current system unless the software is cycled.

Configuration Menu - MAC Address

Configures the MAC address assigned to the USB network interface. The MAC address should consist of 6 octets and is provided in the typical ordering with OUI first. When the Auto MAC Assignment mode is enabled, this will not be used as the MAC address will be derived from the MCU serial number instead.

The command accepts address in two forms:`` AABB1234DF`` or`` AA:BB:12:34:DF``.

Configuration Menu - Auto MAC Assign

Enables or disables the automatic MAC USB network address assignment at power up. When enabled, the MAC address is derived from the unique identifier of the MAX32690 MCU. The upper 3 octets will be ADI’s OUI (00:E0:22) and the lower 3 octets based on the unique identifier. When disabled, the value in the user-specified MAC Address will be used.

Configuration Menu - USB Sniffer Mode

Enables or disables the sniffer feature of the software, which silently drops the frames received on the USB network link. This command represents the default power on state of sniffer mode. See the Sniffer section for information on runtime configuration.

Configuration Menu - Load Default Settings

Restores the configuration to the default settings:

PLCA
- ID: 0
- Count: 18
- Enabled
- TO Timer: 32
- Burst Timer: 128
- Burst Count: 0
VLAN Filtering
- Disabled
- Block Mode: Off
- ID1: 0
- ID2: 0
ETHTYPE Filtering
- Disabled
- Block Mode: Off
- ID1: 0
- ID2: 0
MAC Address: 00:E0:22:FE:70:F0
Auto MAC Assign: Enabled
USB Sniffer Mode: Off

Configuration Menu - Reboot

Performs a soft reboot of the system without needing direct access to the hardware or reset button. This allows a quick shortcut to have the saved configuration settings get applied to the system.

PLCA Config Menu

Opens the PLCA Configuration Menu.

PLCA Config Menu - PLCA ID

Sets the PLCA ID for the AD3306 node on the bus. When PLCA is enabled, each node on the network should have a unique ID. This will have no effect if PLCA is disabled.

PLCA Config Menu - PLCA Count

Configures the number of PLCA nodes on the T1S network. This option will have no effect if PLCA is disabled.

PLCA Config Menu - PLCA Enabled

Enables or disables the PLCA operation of the AD3306. When in USB sniffer mode, this value is ignored, and PLCA is disabled automatically.

PLCA Config Menu - PLCA TO Timer

Configures the transmit opportunity value for the PLCA, setting the minimum duration of the PLCA transmission. Value is in units of Tbits.

PLCA Config Menu - PLCA Burst Timer

Configures the burst timer, setting the maximum wait time for a new packet in burst mode. Value is in units of 100ns.

PLCA Config Menu - PLCA Burst Count

Sets the number of frames the node can transmit in burst mode.

VLAN Filter Config Menu

Opens the VLAN Filter configuration menu.

VLAN Filter Config Menu - VLAN Filter enable

Enables or disables the VLAN filtering functionality.

VLAN Filter Config Menu - VLAN Block Mode

When enabled, the filter mechanism will block/filter out all matching VLAN frames, passing non-matching frames. When disabled, allows the matching VLAN frames, blocking non-matching frames.

VLAN Filter Config Menu - ID1

Sets the VLAN ID in filter slot #1.

VLAN Filter Config Menu - ID2

Sets the VLAN ID in filter slot #2.

ETHTYPE Filter Config Menu

Opens the ETHTYPE filter configuration menu.

ETHTYPE Filter Config Menu - ETHTYPE Filter enable

Enables or disables the ETHTYPE filtering functionality.

ETHTYPE Filter Config Menu - ETHTYPE Block Mode

When enabled, the filter mechanism will block/filter out all matching ETHTYPE frames, passing non-matching frames. When disabled, allows the matching ETHTYPE frames, blocking non-matching frames.

ETHTYPE Filter Config Menu - ID1

Sets the ETHTYPE ID in filter slot #1.

ETHTYPE Filter Config Menu - ID2

Sets the ETHTYPE ID in filter slot #2.

AD3306 Debug Menu

The AD3306 menu provides advanced debug capabilities with direct access to the AD3306 MACPHY.

This menu allows direct register writes to the device which can impact the operation of the AD3306 within the bridge software. This is intended for software development and debug use only.

Read Register(s)

Allows direct reading of register(s) on the AD3306 MACPHY. Different register spaces may be selected by a Memory Map Select (MMS) value. Each register read command requires a MMS argument and register address argument. Optionally, a count value may be given which will read the number of sequential registers at once. If no count is given, a single register will be read. The mms , reg and count may be provided in decimal or hexadecimal notations, with hexadecimal expecting a leading 0x prefix.

The resulting data will be presented on screen in the format <MMS><ADDR> - <VALUE>

Example (Single):

Example (Multiple):

Write Register

Allows direct writing of a register on the AD3306 MACPHY. Each register write command requires a MMS argument, register address argument and value argument. The mms , reg and value may be provided in decimal or hexadecimal notations, with hexadecimal expecting a leading 0x prefix.

Re-Programming

To simplify software updates, the T1S USB bridge utilizes a drag and drop USB-based bootloader for loading new software. See the Bootloader section for information on entering bootloader mode. Once bootloader mode is active, the system will appear as a mass storage device. Below is the expected storage device while running Windows.

img_uf2_drive

To reprogram the board, drop the provided .UF2 file into the mass storage drive. Once the programming is complete, the system will automatically restart into the main software. You can confirm the software version was loaded correctly through the info command in the main menu of the console interface.

The .UF2 files will be available with each release on Github.

Note

There is a known issue on Windows machines where due to the speed the device updates the flash during the drag-and-drop process and immediately resetting to run the application, Windows may throw an error about the device no longer existing. This can be ignored clicking the cancel button.

Note

There is a known issue on Mac OSX machines where once the UF2 file is copied, an error notice might appear stating “The Finder can’t complete the operation because some data … can’t be read or written”. This can be ignored by pressing OK.

Note

An additional notice of “Disk Not Ejected Properly” may appear. This can also be ignored (dismiss by pressing the notice close or cancel).