Ethernet.begin(mac) - MAC not set to the value passed

Official Hardware Portenta Family Portenta H7
1

I am runing this code with the standard 1 of 20 mac addresses randomly selected from a table, or using a 24AA02E48 chip, that has a unique IP address.

When running - I confirm that I pass the correct IP address to the Ethernet.begin(mac) function.

When in windows I execute

ping myIP
arp -a

The mac address of the IP address of the arduino portenta device, is not the one that is set. The unique one, is unchanging, but not the same.

Does anyone else see the same behavior?

Does the portenta have its own internal unique MAC address?

2

Without more information I will take a SWAG and say you are probably setting the MAC with HEX digits and printing it with Decimal numbers.

3

If only that easy.

The MAC address numbers - when coming from the unique on saved in EEPROM, they are printed in hex, and then viewed with arp -a in a powershell in hex as well.

When the MAC comes from the random list - they are arranged (copied from the Async Web Server examples) in hex, and again viewed in hex.

If anyone has a portenta up and running - and are using the MAC addresses from a list like that below, see if the mac assigned belongs to one in the list.

byte mac[][NUMBER_OF_MAC] = {
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x01 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x02 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x03 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x04 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x05 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x06 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x07 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x08 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x09 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0A },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0B },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0C },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0D },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0E },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x0F },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x10 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x11 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x12 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x13 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0x32, 0x14 },
};