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High resolution Voltage Source (replaces pots)

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  • High resolution Voltage Source (replaces pots)

    I've been asked for this a few times, so I thought I'd try to come up with something.

    The resolution of the potentiometers in Proteus is not very good.
    The best you can get is 100 steps full range.
    This makes it difficult to see what effect small steps can have on the analog inputs when you are using 10-bit A/D with 1023 steps.

    So this small circuit uses a MAX5822 (12-bit Digital to Analog converter) controlled by a PIC12F1840 by way of a virtual terminal.

    It can work in any of 8, 10 or 12-bit resolutions, allowing up to 4095 steps.
    The MAX5822 has two separate DAC outputs, and you can control both of them individually.

    You can enter the desired voltage as 0.000 (3 decimal places), or as the D/A value (0-4095 for 12-bit resolution). Or the +/- keys will increment/decrement the selected channel.

    Just connect your circuit to the VA and or VB nets, and tell it what voltages to output.

    The 12F1840 runs a compiled .HEX file, so you don't have to worry about trying to compile it.



    Copy the items to your own design sheet. And copy the .HEX file into the same folder as your design.
    The terminal can be placed over the parts to use less space on the sheet.

    The design was drawn in Proteus version 7.10 SP1 (the current version as of this writing) and will not run on earlier versions.

    HTH
    Attached Files
    PBP3 Manual : Microchip Datasheets - 10F, 12F, 16F, 18F
    Never download a PIC datasheet from anywhere but microchip.com

  • #2
    Missed it

    Just missed it. I have SP0. My update facility has expired and can't afford to renew it now Any chance to get it for a version below??

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    • #3
      I can understand that.
      Upgrading Proteus isn't as easy as upgrading PBP.

      So I downgraded to Proteus 7.6, which was as far as I could go.
      Had to change the PIC to a 16F88 since the 12F1840 wasn't added until Proteus 7.9.
      It only takes up a little more sheet space, and you can overlap the parts if needed.

      A few modifications to the program, and now anyone with 7.6 or higher should be able to use it.



      Same as before:
      Copy the items to your own design sheet. And copy the .HEX file into the same folder as your design.
      Attached Files
      PBP3 Manual : Microchip Datasheets - 10F, 12F, 16F, 18F
      Never download a PIC datasheet from anywhere but microchip.com

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