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Why XDS560 plus connector so short?

Anonymous
Anonymous


Hi All,

I would like to ask a question on JTAG emulator.

I am using a XDS560 plus emulator with a DM6437 EVM. One thing I have found is that the wire (parallel? see picture below) of the connector is particularly short. I in fact found it is quite inconvenient to move the EVM board since the short connector from emulator restricts the movement of the board, and this sometimes become awkward if more peripherals are connected onto the board..

 

 

I read from Wikipedia that

Cable length: Crosstalk creates interference between the parallel lines, and the effect worsens with the length of the communication link. This places an upper limit on the length of a parallel data connection that is usually shorter than a serial connection.

Is XDS560 using a parallel connection? Is this the reason why the bus is short? But the lower part of the above picture was from Spectrum's Emulator Comparison Grid, and it seems that XDS560v2 uses USB, Ethernet. Isn't USB a serial bus? What about Ethernet? If both are serial, why the connector is still made so short?

Or is XDS560V2 the same as my XDS560 PLUS?

 

 

Thanks,

 Zheng

 

 

  • 0
    TI__Guru**** 162905 points

    Zheng,

    I don't know of anything called an XDS560 PLUS.  The picture you have is a Spectrum Digital USB510.  Spectrum also has a USB510 PLUS, the cable on the USB510 plus is a about twice as long as the one on the USB510 so I suspect you have a USB510.  Different emulator manufacturers create various products, some have short cables some have long cables.  The cost of the cables is quite high so most have short cables.  The older XDS560 emulators, like the TI PCI one or the Blackhawk USB560M have very long cables.  However these are pretty expensive and most people prefer the ones with the shorter cables unless they need the long one to access into a rack.

    The Spectrum Digital XDS560v2 is a new generation of emulator.  It has a longer cable than the USB510.  There is a picture here: http://www.spectrumdigital.com/product_info.php?products_id=236

    Regards,

    John

  • Anonymous
    0 Anonymous in reply to JohnS

    Dear John,

     

    I am sorry that I missed your reply on this, and I thank Ki-Soo Lee for verifying it for me.

     

     

     

     

    Why the emulator cable expensive? I guess it is because emulator is doing a very high speed communication with the DSP so that there are special requirements on the material? Because the DSP could work at as fast as over 600MHz and the emulator needs to be synchronized with the DSP clock (via XDS_TCK pin? How is the frequency?) in some manner, and this http://en.wikipedia.org/wiki/Joint_Test_Action_Group wiki article seems to suggest that TCK speed can vary, and there are also additional data in-and-out transferring, so high speed signal lines are essentially for a fast JTAG emulator?

     

     

     

    Thanks,

    Zheng

  • 0 in reply to Anonymous
    TI__Guru**** 162905 points

    Zheng,

    There is quite a bit of shielding in the cable and even active components to prevent interference.  I am a CS guy and not EE so I can't provide much detail.  The XDS560v2's use a different type of cable

    John

  • Anonymous
    0 Anonymous in reply to JohnS

    Dear John,

    Could you confirm with some EE people on this for me?

     

    Zheng

  • 0 in reply to JohnS
    TI__Expert 4995 points

    The older XDS560 cables that were very long were expensive because they utilized micro-coax cable and were proprietary. This was to maintain signal from the target until it reached the emulator. For XDS560v2, we changed the approach and utilize electronics right at the end of the cable to boost the signal, removing the need for micro-coax and allowing us to use a commodity, standard cable.

  • Anonymous
    0 Anonymous in reply to Steve2181

    Dear Steve,

    I see it, thanks for explanation.

     

    Zheng