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CCS/ADS131A04EVM: SSI bus for ADS131A04EVM

Chunwu Wu
Prodigy 10 points
Part Number: ADS131A04EVM
Other Parts Discussed in Thread: ADS131A04, , EK-TM4C1294XL

Tool/software: Code Composer Studio

I choose ADS131A04 24 bit ADC for my project.  I bought the ADS131A04EVM EV board to jump start the project.  I got it work with Delta-Sigma ADC Evaluation tool.  I notice it uses TM4C1294.  So I thought maybe I can get the source code for TM4C1294 and speed up the project.  I looked for the source code for the firmware for the ADS131A04EVM.  TI forum said the source code is not available.  I do not understand the logic behind this.  TI is a chip company.  Why not give your source code for your evaluation board to users so that they can use your chip in their product?

Anyway, TI forum said the source code is not available and ask users to looking at SSI interface for TM4C1294 evaluation board.  So I bought EK-TM4C1294XL board to study this micro chip and its SSI interface.  After some struggle, I am able to get the SSI spi_master project working.  However, there still one problem.  The spi_matser.c example use SSIDataPut function to put number one at a time in the SSI bus.  This results the FSS chip select line to go high after each number segment.  But the ADS131A04 chip expect the FSS chip select line to stay low during the entire 5 24-bit data transmission.  Once the FSS goes high, ADS131A04 stops data transmission.

Could someone either find the source code for the ADS131A04EVM or tell me how to transmit several numbers on SSI interface and has the FSS stay low during the transmission for all the numbers?

I attach 2 photos here.  First is the signal on SSI bus on the ADS131A04EVM.  Second is the signal on SSI bus on the EK-TM4C1294XL.

Thanks for your help.

   

  • 0
    TI__Guru* 92655 points

    Chunwu,


    We don't give always the source code for our EVMs because the software is built on a platform that supports many different devices. Because of this, the source code for particular device EVM may be written in a way that may be hard to follow (not written in a way that would be easy to copy and reuse). Additionally, sending out software now is subject to export control and any example code that we give as example is subject to review before being sent out.

    I do know that there is some example code that is in the works for the ADS131A04. I'll need to see where in the process it is and if it's near ready for release. I believe that this particular example code is written for the MSP432E Launchpad. I would imagine that the device is not similar to the TIVA and may not port over well. I'll need to follow up with you on that.

    If you continue to use the use the TM4C1294XL, I may be able to check on how the code's used with the SSI bus, but I would also check with the TM4C forum just in case. Follow the link there, if you like.

    https://e2e.ti.com/support/microcontrollers/other/f/908

    Additionally, I know there are a few errors in the ADS131A04EVM. I've listed them here:

    https://e2e.ti.com/support/data-converters/f/73/t/781986


    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Guru* 92655 points

    Chunwu,

    In my last post, I mentioned that we're still working on releasing example code for the ADS131A04. I did find a reference to some different example code in a TI design that's referenced in this post:

    https://e2e.ti.com/support/data-converters/f/73/t/684834

    I'll close this post for now, but you can post back with additional questions later if you continue to have problems. I'll also post back when the example code is released.

    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Guru* 92655 points

    Chunwu,

    In one of my previous posts I mentioned that we were in the process of releasing some example code for the ADS131A04. It's not from the EVM, but it does show how code can be written for this device.

    It can be found in the Design and Development tab of the ADS131A04 product folder, but there is a direct link to a zip file here:

    http://www.ti.com/lit/zip/sbac267

    Joseph Wu