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[Mimas V2] Goes analog... Analog In without external Hardware :)

Discussion in 'FPGA Boards' started by analog_digital, Aug 10, 2017.

  1. analog_digital

    analog_digital New Member

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    Once upon a time, long ago, there was analog. Then came the digital, to make our lives easier.


    A few days ago, I noticed on my MimasV2, the header P4. It reports
    • 3v3
    • AN1
    • AN2
    • GND

    Well, I thought, I have 2 pins, and I would like to give a more "analogic touch" to my MimasV2. Looking at the schematic, the answer came almost by itself:

    [​IMG]

    We have the possibility to read the analog voltage from pin AN1 and generate a pwm wave on AN2 with a duty cycle proportional to the voltage value. The following image makes the idea of what's going on. In reality things are different, but I think seeing it from this point of view is clearer.

    [​IMG]

    Now it's just to read the duty cycle from any GPIO pin of the FPGA and… voila. Do you think It’s possible? I say yes. You can find in reply #5 of my post about the custom firmware for pic, and the bin file to test it and ASAP I will upload the Sample project for Xilinx Ise.

    So, to get started with demo:
    1. Flash Custom Firmware
    2. Connect Pin AN2 [header P4] - Pin 8 [header P6]
    3. Connect pin AN1 to voltage you want to sample [0 - 3.3V]
    4. - Setting DIP8 - Fast Displayng
      - Setting DIP7 - Slow Displayng
      - Pushing Switch 4 - Fast Displayng
      - Pushing / Setting Nothing - Display Last Value
    5. for a fast loopback FPGA-ONLY test, connect Pin 8 [header P6] to Pin 7 [header P6] and set DIP1
    [​IMG]

    This is a Quick video showing a brief demo:


    This is the schematic on FPGA:
    [​IMG]
     
    Last edited: Aug 11, 2017
    rohith likes this.
  2. analog_digital

    analog_digital New Member

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    Reserved for some other things i've in mind :)
     
  3. rohith

    rohith Moderator Staff Member

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    Wow! Really fabulous work there! The video makes it look even more better! Excellent! ;)
     

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