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  1. timothyjackson

    timothyjackson New Member

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    Sep 15, 2004
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    Hello there,

    Would like to look into making usb powered devices.

    Is there is a central advice point for making usb devices? How difficult is it? I'm imagining, usb cables can be bought, and, I wire them into my own circuit??

    What power outputs do they typically give?

    :)
     
  2. checkmate

    checkmate New Member

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    If you only want to tap USB power, then just connect the Vdd pin to your socket. USB provides 100mA of +5V power when unconfigured.
    If you want to use USB for comms, then it's an altogather different matter.

    Those usb-to-serial convertors are as simple as rs232 comms. If you want real usb connectivity, then be prepared to spend a long time on it to develop both device firmware and host driver + application. But hey, you can unlock the full 500mA of power for your device. :p

    http://www.usb.org
    http://www.beyondlogic.org/usbnutshell/usb1.htm
     
  3. bmcculla

    bmcculla New Member

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    Location:
    California, USA
    Take a look at Silicon Labs USB controller. They provide a host driver and firmware for the slave that implements simple duplex communication. You just use the API on both sides and don't have to worry about the details. The controller is a very fast 8051 with JTAG debug.
     
  4. dave

    Dave New Member

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  5. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    MicroChip make a PIC with a built-in USB interface, if you're looking for a proper USB connection. But be aware USB is vastly more complicated than a serial connection, however, MicroChip provide sample code for both ends of the link.

    As already mentioned, it's far easier to use a USD/Serial converter, which provides all the required software.
     
  6. timothyjackson

    timothyjackson New Member

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    Was just a quick thought.

    Really amazes me how user friendly microchip really is.

    Will check out the "PIC with a built-in USB interface".

    Thanks
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Be aware that the 16C745 is an OTP chip, so you need to buy the UV eraseable (JW) version for development.

    I seem to remember that MicroChip were bringing out a FLASH version, but I've not checked recently.
     

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