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hex file download problem to card

Discussion in 'Embedded' started by ba by, Jan 31, 2014.

  1. ba by

    ba by Guest

    i use a rs 422 converter with 4 terminal but i could not download hex to card from pc... what is the problem? about converter connection or about flash program?

    In connection, 1 is T+, 2 is T-, 3 is R- and 4 is R+. And R+ goes to T+. R- goes to T-...... ..and so on as said in datasheet. The converter is in SIM mode...


    what can be the problem??? com port is found by pc, and being connected.. but when pressing download, i get an error like this: "Error during Downloading. Connection is closed"... What is this about?? The program is xc800 fload 4.7 . Thanks...
    ba by, Jan 31, 2014
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  2. ba by

    Rich Webb Guest

    Assuming that you have properly set the baud, data bits, stop bits,
    and parity, try swapping the polarity of the T and/or R lines. One
    side of a data link or the other always seems to get it wrong.

    Also, I'm not familiar with the XC800 FLOAD application, so check as
    well that you don't need to have any handshake lines (DTR, etc.)
    hooked up to trigger or to pace the hex file load.
    Rich Webb, Jan 31, 2014
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  3. ba by

    upsidedown Guest

    Hard to say, since you did not say what switch settings you are using
    on the converter.

    Please note that one manufacturer might call the same signal TX+,
    while the other calls the same signal TD-

    Those are unofficial notations for the RS-422 pins.

    The only reliable RS-422 notation is the names used in the actual
    RS-422 standard. The transmit pair is called A/B and the receive pair
    is A'/B'. You connect A to A' and B to B'. Do not rely on T+/TD+/D+
    unofficial notations, since these vary from vendor to vendor.
    upsidedown, Jan 31, 2014
  4. ba by

    ba by Guest

    Hi, i am using such a simple connection.... I use ADM488 pins (8,7,6,5) which are directly going through converter on board schematic. I think i am doing sth wrong here... But i cant find what is wrong.... I tried to swap cables in different modes but i got same error again. I also put jumpers on downloading phase. I cant understand what is problem :(((

    what is your full mail adress ? i can send the photo of converter and pin scheme to yoou.... but i cant see your mail

    31 Ocak 2014 Cuma 21:24:19 UTC+2 tarihinde yazdı:

    31 Ocak 2014 Cuma 21:24:19 UTC+2 tarihinde yazdı:
    ba by, Jan 31, 2014
  5. Some vendors are a bit sketchy about A and B too ...

    Nick Leverton, Feb 1, 2014
  6. ba by

    ba by Guest

    hmmmm, you say that T+ may not be T+ actually....


    Can you suggest me anything that i am supposed to do on which cable??? You can look at the photos above. I indicated the pin numbers on card schematic.. I hope you can help me..and i can understand what to change.. Thanks

    1 Şubat 2014 Cumartesi 02:43:28 UTC+2 tarihinde Nick Leverton yazdı:
    ba by, Feb 1, 2014
  7. ba by

    ba by Guest

    i put jumpers before downloading the hex code:

    I am connecting it ( i think)

    But i end up with getting this error :((


    1 Şubat 2014 Cumartesi 03:16:52 UTC+2 tarihinde ba by yazdı:
    ba by, Feb 1, 2014
  8. You may also need to connect signal ground between the two devices
    (unless both have signal ground connected to earth ground they are
    sharing an earth ground).
    Grant Edwards, Feb 1, 2014
  9. ba by

    upsidedown Guest

    Make sure you get the switches right, especially T-ON/R-ON to activate
    the transmitter.

    On the RS-232 check the DCE/DTE switch.
    On the RS-422/485 side, check that transmitter is always o.

    Perform the "loop back test", use e.g. Hyperterminal to type some
    characters and observe that the characters are echoed on the screen.
    Remove the jumper and nothing should be echoed. This will test that
    the converter is working as expected.
    upsidedown, Feb 1, 2014
  10. ba by

    upsidedown Guest

    upsidedown, Feb 1, 2014
  11. ba by

    upsidedown Guest

    Assuming the posted diagram and pin assignments are OK, there are 100
    terminator resistors between A/B and A' / B' pairs and assuming 1 V
    voltage drop in each totem pole transmitter transistor, the voltage
    swing with a short cable is about +/- 30 mA, so you get a hefty
    signals across the receiver pins, with definitively are going to
    provide the receiver with sufficient receiver transistor base bias
    current, even without a signal ground connection.

    The situation might be different if the devices are in different rooms
    grounded to different earth potentials, but in this case, it is quite
    unlikely to be the problem.
    upsidedown, Feb 1, 2014
  12. That's immaterial. The problem with running without a signal ground
    connection is not the amplitude of the differential signals, it's
    whether or not the common-mode voltage stays within the spec's for the
    That's only true if signal ground is connected to earth ground in both
    ends and both ends share earth ground. If you look at the second
    diagram there are two different grounds shown: the signal ground and
    "GND-ISO" which is using the earth/chassis ground symbol. That
    probably means that signal ground is isolated from earth on that end.

    When using RS-422 and RS-485 you need to connect signal ground if you
    want reliable communications. Relying on a shared earth ground to make
    sure that differential signals are within the common-mode voltage spec
    of the receiver is the sure mark of an hack, and I've seen it cause
    countless problems during the 30 years I've been working with RS-422
    and RS-485.
    It may or may not be a problem. When you don't connect a signal
    ground, your're always just rolling the dice and hoping for the best.
    Grant Edwards, Feb 1, 2014
  13. ba by

    ba by Guest

    Dear friends, i tried by connecting grounds of two cards and converter... but nothing changed. my error does not occur due to grounding.


    I think, it is about flash size.... and dont know what to do guys....

    1 Şubat 2014 Cumartesi 19:24:43 UTC+2 tarihinde Grant Edwards yazdı:
    ba by, Feb 4, 2014
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