+ Post New Thread
Results 1 to 9 of 9
  1. #1
    Newbie level 4
    Points: 31, Level: 1

    Join Date
    Oct 2019
    Posts
    5
    Helped
    0 / 0
    Points
    31
    Level
    1

    Implementation of ADC

    Hello,

    Can anyone help me to know that is it possible to implement any ADC on FPGA board by using Verilog code? Or should i have to go through circuitry, and here i am not talking about implementation of onboard ADC or some external readymade ADC .

  2. #2
    Newbie level 4
    Points: 31, Level: 1

    Join Date
    Oct 2019
    Posts
    5
    Helped
    0 / 0
    Points
    31
    Level
    1

    Implemetation of ADC

    Hello,

    I want to know that can any adc implementation on fpga board by using verilog code is possible or not? Here i am not talking about implementing the onboard adc or using external readymade adc. Can anyone help me please



    •   AltAdvertisement

        
       

  3. #3
    Super Moderator
    Points: 260,308, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    45,462
    Helped
    13829 / 13829
    Points
    260,308
    Level
    100

    Re: Implemetation of ADC

    It's not possible without an analog function. Verilog is only describing digital signals.

    I have seen the FPGA development boards that implemented a simple first order sigma-delta ADC by utilizing a differential LVDS input as comparator and a digital output with an RC low pass as feedback DAC.


    1 members found this post helpful.

    •   AltAdvertisement

        
       

  4. #4
    Advanced Member level 5
    Points: 24,294, Level: 37
    barry's Avatar
    Join Date
    Mar 2005
    Location
    California, USA
    Posts
    4,659
    Helped
    1032 / 1032
    Points
    24,294
    Level
    37

    Re: Implementation of ADC

    You need more than Verilog code, you need analog circuitry to implement an ADC: comparators or opamps, etc. Unless your FPGA has those features, you're not going to be able to create an ADC.



    •   AltAdvertisement

        
       

  5. #5
    Advanced Member level 3
    Points: 5,927, Level: 18

    Join Date
    Feb 2014
    Posts
    845
    Helped
    280 / 280
    Points
    5,927
    Level
    18

    Re: Implementation of ADC

    You'll find a handful of tricks for using digital FPGA pins as an ADC. For example an LVDS input is basically a comparator. If your FPGA has that as an option you can compare an unknown input to a voltage ramp. That voltage ramp can be generated by a PWMing another FPGA pin that's filtered with an RC. See here:

    https://www.digikey.com/Site/Global/...4147EAD25E9F93

    But that's a bit of a hack. Generally if you want an ADC you should buy one and interface it to your FPGA (SPI is a good choice) or choose an FPGA that has an ADC built in (many do these days).


    1 members found this post helpful.

  6. #6
    Newbie level 4
    Points: 31, Level: 1

    Join Date
    Oct 2019
    Posts
    5
    Helped
    0 / 0
    Points
    31
    Level
    1

    Re: Implementation of ADC

    Thanks for reply, Actually i don't want to use inbuilt ADC and also don't want to buy any ADC to interface with my FPGA. Instead of these i want to implement my own ADC and i know it is possible by making circuitry in Cadence or some other software, but my concern or question is, Instead of designing a circuit is it possible to implement complete ADC by using verilog programming?
    If Yes, then how we can write program for Analog part?

    Thank you



  7. #7
    Advanced Member level 5
    Points: 24,294, Level: 37
    barry's Avatar
    Join Date
    Mar 2005
    Location
    California, USA
    Posts
    4,659
    Helped
    1032 / 1032
    Points
    24,294
    Level
    37

    Re: Implementation of ADC

    Read post #3 again. adsff explains how to use the digital elements of an FPGA to effect analog functions. But you can't "write program for analog part" in Verilog, but you can write the digital control part.


    1 members found this post helpful.

    •   AltAdvertisement

        
       

  8. #8
    Newbie level 4
    Points: 31, Level: 1

    Join Date
    Oct 2019
    Posts
    5
    Helped
    0 / 0
    Points
    31
    Level
    1

    Re: Implementation of ADC

    Ok Thankyou all for helping me, but can i take any analog signal from matlab or any other software and store it and attach it to my verilog program as analog input signal of ADC and see the results in any software like chipScope pro ,is it possible?

    By the way i am using Xilinx ise for verilog programming



  9. #9
    Super Moderator
    Points: 31,634, Level: 43
    ads-ee's Avatar
    Join Date
    Sep 2013
    Location
    USA
    Posts
    7,317
    Helped
    1719 / 1719
    Points
    31,634
    Level
    43

    Re: Implementation of ADC

    Quote Originally Posted by student21 View Post
    Ok Thankyou all for helping me, but can i take any analog signal from matlab or any other software and store it and attach it to my verilog program as analog input signal of ADC and see the results in any software like chipScope pro ,is it possible?

    By the way i am using Xilinx ise for verilog programming
    Do you understand the difference between analog and digital signal? A Xlinx FPGA is a digital device it works with two voltage states to do something. It can't use analog signals to suddenly work as an analog device.

    You can't take an analog signal and stick it into a Verilog program. You can digitize an analog signal, which is why the devices that do this are called Analog to Digital Converters (ADC). You could generate a signal from matlab or other software and format it into fixed point, integer or even IEEE float and load the equivalent binary or hex data into an array in Verilog to read out over Chipscope Pro, but why?

    I don't understand your objective here, what you seem to be trying to accomplish is better done using an actual ADC. If you are trying to learn about FPGAs then what you are attempting is, IMO, a complete waste of time.



--[[ ]]--