Change ethernet MAC address on Nucleo-H753ZI board

[vsp-dev-sys]

Hello,

I’m new to MicroPython and have successfully built and deployed firmware from source for the ST Nucleo-H753ZI board. The network module functions correctly, and I’ve observed that flashing the same binary across multiple Nucleo-H753ZI boards generates unique MAC addresses for the Ethernet interface.

For my application, I need to:

Customize the MAC address for each board during setup.
Implement a command-line utility to dynamically modify the MAC address at runtime.

However, I’m unable to locate where the MAC address generation is handled in the MicroPython source code. Could someone provide guidance on:

Where the MAC address assignment logic resides in the codebase?
Steps to integrate a custom MAC configuration per device?
Recommendations for creating a runtime MAC modification tool?

Any insights or pointers would be greatly appreciated.

Thanks

[bikeNomad]

Have you tried passing the MAC address (as phy_addr) to the network.LAN constructor? See https://docs.micropython.org/en/latest/library/network.LAN.html#network.LAN

network.LAN(id, *, phy_type=<board_default>, phy_addr=<board_default>, ref_clk_mode=<board_default>)

Create a LAN driver object, initialise the LAN module using the given PHY driver name, and return the LAN object.

Arguments are:

id is the number of the Ethernet port, either 0 or 1.

phy_type is the name of the PHY driver. For most board the on-board PHY has to be used and is the default. Suitable values are port specific.

phy_addr specifies the address of the PHY interface. As with phy_type, the hardwired value has to be used for most boards and that value is the default.

ref_clk_mode specifies, whether the data clock is provided by the Ethernet controller or the PHY interface. The default value is the one that matches the board. If set to LAN.OUT or Pin.OUT or True, the clock is driven by the Ethernet controller, if set to LAN.IN or Pin.IN or False, the clock is driven by the PHY interface.

[vsp-dev-sys]

Hello @bikeNomad ,

Thanks for your response. I did give it a shot, however, on the Nucleo board port, it does not seem to work.