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RFID serial to usb — Parallax Forums

RFID serial to usb

mapsjlmapsjl Posts: 3
edited 2010-06-02 00:34 in Accessories
I have a serial version of the RFID reader and one of the USB2SER development tools. Does anyone know how I can wire them together?

Comments

  • NatureTMNatureTM Posts: 3
    edited 2010-05-31 17:32
    If the USB2SER is 5V, connect 5V on USB2SER to 5V and /ENABLE on RFID. Ground to ground. RX on USB2SER to SOUT on RFID.
  • NatureTMNatureTM Posts: 3
    edited 2010-05-31 17:32
    Sorry, don't connect 5V to /ENABLE, connect ground to ground and to /ENABLE.
  • mapsjlmapsjl Posts: 3
    edited 2010-06-01 15:06
    So the connections from
    RFID to USB2SER:

    VCC to VSS
    /ENABLE to TX
    SOUT to RX
    GND to RES

    Correct?

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    Jack Maps
    eternal noob
  • Mike GreenMike Green Posts: 23,101
    edited 2010-06-01 15:32
    No no no no!

    The two (RFID reader and USB2SER) don't work together very well.

    1) You can't power the RFID reader from the USB2SER. You'll need a separate +5V supply for the RFID reader connected to VCC and GND.

    2) The RES line on the USB2SER produces a pulse whenever you turn on DTR while the /ENABLE line expects a level that stays low while the RFID reader is to be activated. I'm not sure of the pulse width, but it's probably too short to activate the RFID reader the way it's intended to work. You could just connect the /ENABLE line to GND to leave the RFID reader activated all the time.

    3) As NatureTM mentioned, you connect GND on the RFID reader to VSS on the USB2SER.

    4) Connect SOUT on the RFID reader to RXD on the USB2SER.

    Post Edited (Mike Green) : 6/1/2010 3:43:36 PM GMT
  • mapsjlmapsjl Posts: 3
    edited 2010-06-01 16:44
    Thank you!

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    Jack Maps
    eternal noob
  • NatureTMNatureTM Posts: 3
    edited 2010-06-02 00:34
    Sorry for the bad info. I bought one of the discount readers at radio shack and got it working with a microcontroller the other day. I just glanced at the USB2SER spec sheet and gave a response when I should have made more of an effort to be sure I was giving good info.
    As far as the /ENABLE pulse length, I found that it likes 500ms or greater. It's still just a little flakey at 500 ms and I use 1000 ms because that seemed to work every time. The real "perfect" pulse length is probably somewhere in between, but I didn't spend too much time on finding it, as power consumption is not a major factor in my application.

    I'll try to do my research a little better in the future before posting solutions for products I have never used! smile.gif
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