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Thread: Has anyone ever tried this IC?

  1. #1
    Constant Bitrate Putput's Avatar
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    Has anyone ever tried this IC?

    I was surfing the net looking for quadrature decoder IC's and I found this! (Please read the PDF file)
    It's a preprogrammed PIC that can handle 3 quadrature encoders (optical and/or mechanical) in its simplest form and 6 digital inputs. And last but not least it has a direct generic USB HID interface meaning that no drivers are required on the OS side and programming plugins for any frontend should be a piece of cake. This means that installing rotary encoders like these on a carpc and integrate it into frontends should be very easy to do. Except for 2 small capacitors and 1 resistor the PIC doesn't require any external components when used with mechanical encoders/switches so a pre-drilled PCB can be used to solder the PIC on and thats it! Power comes from 5V USB so no external power source required.
    I placed an order via a German website but they have other dealers in different countries, look in Sales page on their website. I'll post more info once I received and tested the hardware.

    Regards,
    Putput

  2. #2
    Variable Bitrate
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    is it programmable?
    Main problem would be switch bounce, without the ability to reprogram the chip, you're limited to debounce the switch by hardware.
    dsatx in voompc 2 case <HERE>

  3. #3
    Constant Bitrate Putput's Avatar
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    Quote Originally Posted by skuller View Post
    is it programmable?
    Main problem would be switch bounce, without the ability to reprogram the chip, you're limited to debounce the switch by hardware.
    I assume that the decoder inputs are already de-bounced because the datasheet containes an example with mechanical switches only. This chip is IMHO programmed for this. I'll let you know as soon as I can test it.

  4. #4
    Fusion Brain Creator 2k1Toaster's Avatar
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    Quote Originally Posted by Putput View Post
    I assume that the decoder inputs are already de-bounced because the datasheet containes an example with mechanical switches only. This chip is IMHO programmed for this. I'll let you know as soon as I can test it.

    Datasheet:
    5.4 Using mechanical encoders
    The use of electro mechanical encoders (i.e.
    encoders that use switches to generate the
    quadrature signals) should be limited to human
    input applications. It is not recommended to use
    electromechanical encoders or switches with
    SW24A3 at all.
    Switches bounce, that means a contact closure is
    not immediate and final, the contact will close and
    open several times for a few milliseconds before
    becoming stable.
    Usually this is compensated by a debounce logic
    either in hardware or software. But adding such a
    debounce logic would restrict the rotation speed
    that can be tracked to a level that feels
    uncomfortable.
    SpinWarrior does not implement such a debounce
    logic for the encoders to allow maximum tracking
    speed. Though this also means some additional
    spurious pulses may be detected.
    Anyways, optical encoders are much better, so I would use those anyways.
    Fusion Brain Version 6 Released!
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  5. #5
    Constant Bitrate Putput's Avatar
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    Quote Originally Posted by 2k1Toaster View Post
    Datasheet:


    Anyways, optical encoders are much better, so I would use those anyways.
    You are correct, missed that part. I'll see what happens when I test it.

  6. #6
    Constant Bitrate Putput's Avatar
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    It Works!

    I received the IC this week and tested it today. It works great, even with electro-mechanical encoders without extra de-bouncing circuitry. I made a quick testcircuit and the device is immediately recognised by Windows and the position of the encoders is directly available in the HID message telegrams. Only thing I have to do now is to write a simple plugin to make it work in my frontend.
    The datasheet indeed describes that mechanical encoders should be 'limited to human input applications' and thats just what I do, no more no less. And if a single click every 200 pulses should create a double input ... so what? It's not a high accurate positioning application, main target here is to turn volume up/down or switch radio stations or something.

    Regards,
    Putput

  7. #7
    Constant Bitrate
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    Putput, Looks very useful.

    Did you ever get to writing your plugin for it?

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