• Resolved

ADS1118evm SPI trouble

Hello I am currently using an ADS1118evm hooked up to a Beagleboard

I just need to make sure I can get voltage readings from the ADC to the beagleboard.

For thw interface I am using SpiMode1 and connecting the ADS1118evm chip select, clck, mosi and miso to the appropriate ports (or at least I hope so)

Here is the code I am using


I am doing a one shot mode read so that I can see how to interpret my raw voltage.

But I don't think I am doing it correctly, is there anything wrong with my code?

Thank you,


  • Hi Alonzo,

    Would it be possible for you to send us a screen shot of your SPI communication with the ADS1118 along with details of how you have the boards wired together?  




  • In reply to Tom Hendrick:

    Yes I can provide them, I am thinking it is either the code or I should purchase some extra alligator clips for this.  I tested the ADS1118evm on the USB connecter and it works just fine:

    photo 1

    photo 2

    photo 3

    photo 4

  • In reply to Alonzo Espinoza:

    Hi Alonzo,

    The pictures that Tom was asking for is oscilloscope pictures of the communication so that we can verify that the clock edges are correct for the spi communication.  A couple of things to keep in mind is CS must be low for the entire communication transaction.  The other consideration is the part defaults to power down single shot mode, so you must write a start conversion to the ADS1118, and then must wait for the conversion to complete before reading out the data.

    It would be good if we can see DIN, DOUT, SCLK and CS signals on an oscilloscope plot.

    Best regards,
    Bob B

  • In reply to Bob Benjamin:

    As Bob mentioned, screen shots from an oscilloscope would be great.  The pictures you did send look like you have simple 'wire loops' on the test points to the ADS1118EVM.  You might consider adding a bit of solder there to ensure you have good connections.




  • In reply to Tom Hendrick:

    Okay thank you, I will try to get the oscilloscope data as soon as I get back into the lab.