How to use AD1955 EVB

I just got the EVAL-AD1955EBZ-ND .

And I have some questions as below:


  1. The user guide UG-048 is not clearly about how to use EVB AD1955, it only shows that
  1. Install Register Window Builder.
  2. Install USBi driver
  3. Use ±12V to supply EVB.


After these steps, how to connect EVB with PC?


2. How could I transmit a single tone signal by EVB?

Is there any document can show the way step by step?


Is anyone can help me to solve these problem??

Thanks a lot.

  • Hello homeaway,

    The user guide does show how everything is setup. So I don't understand your question.

    On page three it talks about using it in standalone mode. In this way the PC is not even required. The eval board is not designed to get its audio from the computer via the USB. The audio must come in as I2S or PDM signals but the evaluation board also has an SPDIF converter that converts SPDIF signals into I2S to make it more convenient to get audio into the DAC for evaluation purposes. The CPLD is there on the eval board to help route data and clocks.

    The USB interface, otherwise known as the USBi, is there to provide a way to look at and set the control registers in the part. It is a USB to I2C/SPI converter. Then the ARWB program is there to provide some software to send and read the commands to set registers. You do not have to use it, you can use a microcontroller to send commands to the part.

    The ARWB program will open up with a blank screen. You then have to load in the file that has the register details for this part. So you go to "File" and then "Open Register Window" and load in the file that has "AD1955" in the name.

    Then you will see the registers. Well, you would have to read all because it opens up with default values.

    You connect the USBi to J26 which is labeled "Control Interface".  You are correct that this is not actually described in the user guide. So that is how the control interface is connected, or an external micro-controller.  

    Then the audio connects either into the SPDIF or using the I2S pins provided. J8 has those connections. There are still other jumpers that may have to be set depending on who is the master and where the signals are coming from.

    So how do you want to set it up for your needs? What do you need to do and perhaps I can be more specific?

    Dave T

  • Hi Dave,

    Thanks for your reply, your explanation is very clear, and  it is very very help me a lot to know the EVB.

    Now I can use ARWB via USBi to connect EVB successfully.


    Actually, I want to measure THD+N perfornance for AD1955 DAC ,so I need to transmit a single tone singal like 10kHz from EVB. I think I have to use other digital audio souce into EVB, then get the output from Analog single ended output (J15 / J23), is it right?

    Or is there any way that can let EVB transmit single tone by it self?

    BTW, my name is Homeway

    Thanks a lot.

    Homeway Chen

  • Hello Homeway,

    That you for pointing out the error in my typing your name!   My fingers automatically add the rest of the English word so I did not notice it. I am laughing at myself! Sorry, I did not mean to do that. You probably see that often. It is a study of what the brain will do to add letters that are missing. Our brains are quite good at doing that but sometimes it is a problem. I would guess the same thing happens in Chinese, you add missing characters and change the meaning? Anyhow, enough of this interesting cultural study.

    There is no signal source on the EVB. You have to either bring it in as an I2S signal. PDM signal, or via the SPDIF interface. Keep in mind that the SPDIF interface is not perfect and will add some distortion due to clocking and jitter etc. I don't remember what the distortion level is on these SPDIF interfaces but it will probably be higher than this DAC.

    So the best way would be to find an I2S signal from an Audio Precision or a DSP with an internal generator.

    Dave T

  • Hello Dave,

    Never mind about it, sometimes I typing the wrong name like you, too. It is really interesting that you said about our brain doing. Thank you for tell me this special opinion.

    Now I still have problem about EVAL-AD1955EBZ.

    Without any control interface, the EVB will run in standalone mode, so when I power on the board, and transmit signal to SPDIF INPUT(J24), then I will get analog signal at analog single ended outs(J15/J23) automatically, is it right? 

    I use Audio Precision to transmit digital signal to EVB, but it still can not work.

    Below is my setting:


     Digital signal source : Audio precision APX 515 : Digital Unbalanced / Sample rate 48kHz ->J24  

                                           Audio precision APX 515 : Digital Optical / Sample rate 48kHz   ->U15

    Input selector(SW1) : SPDIF/OPTICAL

    Mode(SW3) : 0  S/PDIF input, I2S format, 48 kHz~96 kHz fs

    SNGL_END(J12,13,17,18) : EN

    MODE B(SW4) : 0 

    MCLK(SW5) : 256FS


    Is there something wrong?

    I am a rookie in AUDIO region, maybe I will ask stupid question, hope you would excuse me.

    H.W. Chen

  • Hello homeway,

    The only way to figure out what is going wrong is to trace the signals with an oscilloscope. First check that the MCLK is getting to the part.

    J11 pins 2,4, and 6 are all connected together and this will be the MCLK signal going to the DAC. It should be the same signal that is seen on pin 3. This is the master clock coming from the SP/DIF receiver.

    Then check to see if the BCLK, LRCLK and SDATA from the SP/DIF receiver are getting to the DAC. You can see these signals on test points TP17, TP18 and TP23.

    I am wondering if the CPLD is functioning at all.

    Dave T