Ethernet problem

Your question is about as simple to answer as if I would ask "Please help me how to find the color of my t-shirt."

Don't you think it would have been good if you had given a bit more information?

It really isn't so easy to locate a device if you neither know IP nor MAC and you don't know of any broadcast message that the device responds to.

But right now, we don't even know if you have a hardware unit you want to find the MAC for, or if you have the source code but don't know where the MAC is specified.

Actually, we don't know basically anything, except the name of a specific chip. The datasheet for that chip doesn't seem to indicate that there are any magic display on it that will present the used MAC address.

You might be able to do
> ping 255.255.255.255
or
> ping 224.0.0.1

And check your arp table.

But not all devices cares about broadcast ping or multicast ping.

Or you might consider using the program arp-scan

Your question is about as simple to answer as if I would ask "Please help me how to find the color of my t-shirt."

Don't you think it would have been good if you had given a bit more information?

It really isn't so easy to locate a device if you neither know IP nor MAC and you don't know of any broadcast message that the device responds to.

But right now, we don't even know if you have a hardware unit you want to find the MAC for, or if you have the source code but don't know where the MAC is specified.

Actually, we don't know basically anything, except the name of a specific chip. The datasheet for that chip doesn't seem to indicate that there are any magic display on it that will present the used MAC address.

You might be able to do
> ping 255.255.255.255
or
> ping 224.0.0.1

And check your arp table.

But not all devices cares about broadcast ping or multicast ping.

Or you might consider using the program arp-scan

The LAN8720 doesn't know or care about the MAC.

So to extend Per's opener, your question is more like: "Please help me how to find the color of my t-shirt. My shoes are black"

i am using the sample code of lpc1788 it is working in development board............ but its not working with the other lpc1788 controller board.

it is having the same pin connections as per development board schematic.
it is showing connected but when we try to ping with the ip address of microcontoller ethernet it is not pinging...

its showing request timed out.

so how to resolve this.

Study carefully at the schematics, source code, and documentation of the working board until you understand how the MAC address is set, stored, and used.

Once you understand how the MAC address is set, stored, and used on the working board, you will be able to trace where that's going wrong on the oher board.

So your original question as made wasn't really relevant then. You have hardware that you don't know if it is correct or broken, and you have thrown in software that you don't understand in it.

Any code inside that board that is managing to make the board send something out, will result in packets that can be sniffed to know what MAC address that is used.

If you understand the code, then you should be able to know how to get the board to try to send something (assuming the hardware is actually working).

If you understand the code and hardware, then you should also be able to know if the code contains a hard-coded MAC address or if there is a MAC address stored in EEPROM or similar.

So why did you make a post where the only fact you bothered to give was "LAN8720" when you could have mentioned what development board you based your own hardware on. Or what software packet you downloaded into your board?

You often go into a car shop and demand to buy a spare part for your car, while refusing to tell them brand and model of car? You think that would be a working route to be able to actually get the correct spare part?