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MSP432E401Y: Ethernet module sends malformed packets

Eugen Volkov
Prodigy 105 points
Part Number: MSP432E401Y

Hello, Support Team.

I use MSP432E401Y on our own board. I write my program in assembly code using Code Composer Studio 10.1.1.

The MSP432E401 sends UDP packets with 42 or 82 bytes payload (common length is 84 or 124 bytes respectively) with interval 40ms or 80ms respectively. The speed is 10 Mbps, full duplex, Inter-Frame Gap = 64 bit times, 7 bytes of preamble. For connecting to PC I use an old SOHO Ethernet hub SE-500.

One day I had noticed strange behavior of the EMAC module. My microcontroller sometimes (very seldom) sends malformed Ethernet packets. The packet begins normally, but since middle its bytes change to 0xAA or 0x55. The common length of the malformed packet also changes (mainly it becomes bigger). I attach some examples got with Wireshark.

Moreover, other Tx packets (ARP-messages, ICMP-messages) can also be malformed. You may notice, that 0xAAAAAAA….. or 0x5555555… in binary is the sequence of …….101010101010101010……. What does it mean for EMAC and PHY module?

I connected other Ethernet hubs. I checked the SRAM while debug session, I tried to change EMAC settings, but nothing helps. I am afraid, that it might be not software, but hardware problem.

Have you ever seen such the malformed packets? Please, help me to find the resolve.

Best regards.

  • 0
    TI__Mastermind 29286 points

    Hi Eugen,

    Have you try MSP430E401 Ethernet example in your hardware?

    I think you should be able to get those example in MSP432E SDK:https://www.ti.com/tool/SIMPLELINK-MSP432-SDK

    Thanks!

    Best Regards

    Johnson

  • +1
    Prodigy 105 points

    Hello.

    Thank you for the reply, Mister Johnson He. I checked that example too.

    Now I have resolved the problem. And I shall tell you how I have managed to do it.

    I took an old device that sends similar packets. It uses other Ethernet controller. But its packets were malformed again. Therefore the blame does not lie with the MSP432E401Y. Then I disable my Ethernet hub SE-500 and connected two devices with MSP432E401Y through an Ethernet bridge with two Ethernet cards in my computer. I have recorded about 200000 packets from the device. And I do not find any packets with wrong length.

    So I am able to conclude that my SOHO Ethernet hub SE-500 deforms packets and deserves blame. The MSP432E401Y acts rightly.

    Best regards.