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HSDC Pro Ver 4.70 Binary Output Data File Numbers

Roger Backhus
Intellectual 425 points

Other Parts Discussed in Thread: ADC3244

Hello,

After some forum help I am able to read and parse the HSDC software output binary data file.  I'm using the TSW1400EVM and the ADC3244EVM.  The ADC3244EVM has a 14 bit ADC3244 converter on it.  The ADC is set to output 2's complement numbers (the register bit setting for this is zero).  Channel 1 has a 10.1 MHz tone going into it and channel 2 is terminated in 50 Ohms.  The spectrum plot for channel 1 looks like I would expect.  So some recorded time ordered, time contiguous read, parsed and printed samples in hex from the HSDC binary file are,

Channel 1 value = 202b
Channel 2 value = 2000
Channel 1 value = 205f
Channel 2 value = 2003
Channel 1 value = 1ff8
Channel 2 value = 2000
Channel 1 value = 1ffd
Channel 2 value = 2004

These numbers do correspond to what I'm seeing in the "codes" plot in the software.  What bothers me is that channel 2 which has no signal applied is recording and showing what corresponds to nearly -2V (negative maximum)  assuming 2's complement format.   I would expect it to record near zero. These numbers would make more sense if the chip were set to output offset binary but I checked the ADC register setting and also reviewed the HSDC Pro users guide to see if it defaults to offset binary and there was no indication of that. So, am I interpreting these numbers correctly?  Are they 2's complement or offset binary?

Thanks 

 

  • 0
    TI__Mastermind 44680 points

    Hi Roger

    I'm glad you're able to read and parse the binary data file.

    The reason the numbers appear to be in offset binary instead of 2's complement is because of some processing done in the High Speed Data Converter Pro software.

    Each ADC used with HSDC Pro has one or more associated .ini files. For the TSW1400, the files are located in this folder:

    C:\Program Files (x86)\Texas Instruments\High Speed Data Converter Pro\1400 Details\ADC files

    For the ADC3244EVM the file used is "ADC324x_2W_14bit.ini".

    Near the top of the file is a section used to provide manipulation of the data as it is pulled into HSDC Pro. In this case the line utilized is:

    Data Postprocessing=1:8192

    Descriptions of the processing commands and an example are provided in-line in the file as follows:
    \\operation:operand
    \\operaion
    \\0=bit shift
    \\1=xor
    \\2=and
    \\3=or
    \\4=not
    \\operand
    \\value(+ve if bitshift by right and -ve if bitshift by left)
    \\E.g 0:-2,1:1024
    \\bitshift by left 2 times and then xor by 1024

    In this case the processing is doing an xor of the data value with 8192 decimal. This will invert the most significant bit of the data, changing it from 2's complement to offset binary.

    If you want to work with 2's complement and don't care whether HSDC Pro can properly calculate FFTs, etc. you can comment out this line of text. Then the binary files exported should give you what you are expecting.

    I hope this is helpful.

    Best regards,

    Jim B