Main Site Documentation

Cobra II Net MAC Address


#1

@ GHI Does each unique Cobra II NET caries the same (unassigned) MAC address?


#2

@ RobvanSchelven - Yes, the default address


#3

@ Mike - Thanks !


#4

you can always use the code I just posted to generate your OWN…

https://www.ghielectronics.com/community/forum/topic?id=13866

Cheers,
Jay.


#5

@ Jay Jay - Nice work! Any side affect to use an online generator like this, if you know?

http://www.miniwebtool.com/mac-address-generator/


#6

@ RobvanSchelven -
Side effects are many, you could be generating a one’s manufacturer’s MAC Address, second you might end up with an invalid Mac…

Please see the WIKI link i have shared in the code share to understand these issues…

Third you will have to use that online generator every time you need a Mac for a board… where using my code you don’t have to since it is automatic :slight_smile: and the Mac it generates are flagged as Locally Administered to the router…

Cheers…
Jay.


#7

@ Jay Jay - Thanks, I have read the pages of the links you provided. Does the random generator always return a unique code even when it starts with an equal string?
If so than the code is very useful.

A better option to be supplied by GHI would be to be able to buy a board or network interface with a MAC address. Especially if the board is used in a commercial applications


#8

Not everyone needs a MAC, so it may be a problem for GHI.
There are (i.e. 25AA02E64 from Microchip.com) chips for <30 cents with unique, registered MAC addresses for different protocols (I2C, SPI, etc.). These might be good if you are selling your products and want something permanent and definitely valid.


#9

I agree, but the idea was that the user has an option to select from, something with or without MAC address


#10

MAC addresses are only included with boards that have an Ethernet PHY chip. The G120 and G400 modules do not include a PHY chip. The EMX module does/did.

If there is a PHY chip on the board, then there is an E socket.


#11

If someone wants to use the Cobra II NET in a commercial application it would be desirable or maybe even obliged to have a ‘legal’ MAC address


#12

Buying a block of 4096 MAC address is a bit expensive if you only need a few.

http://standards.ieee.org/develop/regauth/iab/

For a few, it would be less expensive to buy a chip, extract the MAC, and discard the chip.

http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en538613


#13

@ Mike - That’s a creative good idea. I will have someone talk to GHI directly since they probably already own a block as used for EMX. Maybe they can sell it as an addition to Cobra II Net.


#14

@ RobvanSchelven - I believe the IEEE forbids just the sale of MAC addresses by a block holder. Sale of an address without a PHY with a board is a grey area.


#15

It would be great if GHI would include the identity chip in all of their boards, i mean look they are cheap… $0.40 a piece…

Doing this would shoot two birds with one stone… it can be used as a unique serial number for board identity and for the MAC Address…