This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP432E401Y: Format for Sending Ethernet Frames to a Client

Part Number: MSP432E401Y
Other Parts Discussed in Thread: MSP-EXP432E401Y

Hi,

I'm trying to re-purpose the ethernet_with_lwip example (running on an MSP-EXP432E401Y development board using CCS) so I can receive short (10-byte) commands from a client and respond with a short burst back to the client. With help from a previous post I am able to receive the command successfully. Now I'm trying to send a response back to the client. To make it as simple as possible for now, I'm just trying to send the same 10 bytes that I received (05 64 05 C9 01 00 01 00 90 25).

Here is a typical ethernet frame I'm receiving from the client:

1C76FF70 265C4EBB 251E220A 00450008 63C23200 06800040 A8C0A7B4 A8C00501 C0626501 D04F0050 1980FD95 18500000 ABEBFAF0 64050000 0001C905 25900001 F143669C

And here is my "first guess" attempt at a response:

220A265C FF70251E 4EBB1C76 00450008 61C13200 06800040 A8C0A9B5 A8C06501 50000501 2854FDCD 1B05CC95 18500000 F2B2FAF0 64050000 0001C905 25900001 345D01BD

I'm pretty confident that I have the 6 byte destination mac address, 6 byte source mac address, and 2 byte type values for the ethernet frame header correct. I'm also confident I have the source and destination ip addresses correct in the IP Header, but less confident about the source and destination port #'s in the TCP header. I assume that the options and padding for both the IP header and TCP header have been left out since the data starts after 54 bytes and, after the 14 bytes necessary for the ethernet frame header are subtracted leaves only 20 bytes for each of the IP and TCP headers.

Beyond that, I pretty much don't know what I'm doing. I did a test to record some receive and transmit frames using a browser to give me some flag settings and other values to use for my first guess response but I don't know if they are correct or not. I also have no idea how the checksums should be calculated.

Does anyone know if there are any routines already present in the ethernet_with_lwip example that can be used to generate the response?

Any help anyone can provide that will get me closer to being able to get a response back to the client successfully would be greatly appreciated.

Thank you