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EVM430-F9779 Serial Communication

Kyle Mann
Intellectual 420 points
Other Parts Discussed in Thread: EVM430-F6779

Hello,

Currently I am trying to figure out how the GUI communicates with the EVM meter through serial in order to create my own application to read the three-phase data. I have seen the source code for the board but I am still confused as to what is going on. I am sniffing the serial traffic to my PC with a serial monitor when I run the GUI application. Results are attached. output known hex.txt

Thanks

  • 0
    TI__Guru**** 208927 points
    Hello Kyle,

    I assume we are referring to the EVM430-F6779. I will loop in the Metering Team to help provide more insight into this matter but further review of the source code is still the best approach to deciphering the UART communication. It incorporates the MSP430-ENERGY-LIBRARY and uses a packet-based communication protocol very similar to that shown in SLAA638 (you can see the start, address, and repeated start bytes quite clearly in your output file): www.ti.com/.../slaa638.pdf

    The prepare_tx_message and process_rx_message functions in emeter-dlt645.c and the ISRs in emeter-communication.c will probably be of the most help to you.

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    Intellectual 420 points

    Yes sorry I meant the  EVM430-F6779. Thank you for the PDF that helps alot. After looking at the source code and the pdf, I think I understand the client side commands well enough. I understand the header, length, checksum, commands, and stop bytes. But I still do not understand, on the board tx side, how to extract the phase data from the transmission message. Here is the example I am currently working on. 

    Client command

    [09/06/2016 10:11:54] Written data (COM10)
    fe fe fe fe 68 99 99 99 99 99 99 68 23 02 61 00 ec 16

    so we have a command of 0x61 or get phase 1 readings

    [09/06/2016 10:11:54] Read data (COM10)
    fe fe fe fe 68 99 99 99 99 99 99 68 23 1f 61 80 8f 17 e6 06 60 29 00 00 1c 00 00 00 60 29 00 00 f0 d8 6d 17 09 01 0b 00 f0 5c 82 03 00 7b 16

    Underlined is the data I just am still not understanding how to interpret it, even with the pdf. Below is the data I am expecting to find or close to it.

    Below is the work I have done so far

  • 0 in reply to Kyle Mann
    TI__Guru**** 208927 points

    I did not write the metrology code, here is what I have so far

    You really need to dive into the process_rx_message function, the phase pointer is a great hint.

    Regards, Ryan

  • 0 in reply to Kyle Mann
    Intellectual 420 points

    Thank You! Ah so its little endian. I was able to decipher most of it. However, I'm still not understanding where it transmits phase (if at all) or whats going on with DC.

     

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