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Olimex XDS100v3 shows 'SC_ERR_PATH_BROKEN' error in F28335

Other Parts Discussed in Thread: CONTROLSUITE

Hello Experts,

                     I am is Akhil Francis i am working on DSP f28335, and 14 pin olimex XDS100v3. I connected the olimex XDS100v3 and i powered F28335  from an external power supply. While loading the program i got an error  'SC_ERR_PATH_BROKEN'.

Error is 

C28xx: Error connecting to the target: (Error -233 @ 0x0) The JTAG IR and DR scan-paths cannot circulate bits, they may be broken. An attempt to scan the JTAG scan-path has failed. The target's JTAG scan-path appears to be broken with a stuck-at-ones or stuck-at-zero fault. (Emulation package 6.0.14.5)

Then i checked  each pins of jtag header while loading the target,   i found that

EMU1 is high

EMU0 is low

TRST is getting high low

no pulse in TMS and TCK

TDO and TDI getting high low pulses

Then i checked the controller pins by giving  the power to f28335 ,with out connecting JTAG,   And i found 

Both the EMU pins of controller are high

TDI is high

Is this is correct or not? How can i check/solve this problem? please give me a solution.

Thanks in advance

  • Hi Akhil,

    If this is a custom board, my first recommendation would be to make sure that schematic-wise your board matches the datasheet recommendations.  Please see the section labelled "Emulator Connection Without Signal Buffering for the DSP" in the datasheet:
    http://www.ti.com/lit/gpn/tms320f28335

    The pull-down resistor on TRSTn is especially important.

    ===

    If you are using a TI ezDSP or controlCARD evaluation kit, what kit are you using?


    Thank you,
    Brett

  • Brett,
    Thanks for your timely reply. I checked my circuit it seems schematics are correct. Pull-down resistor on TRSTn is 560 ohm. Should i have to chose any boot mode for checking JTAG integrity test? I checked JTAG integrety test, with out choosing boot modes, i found that JTAG integrity test are failed. After this error i just done debugging , While debugging i got above error.

    C28xx: Error connecting to the target: (Error -233 @ 0x0) The JTAG IR and DR scan-paths cannot circulate bits, they may be broken. An attempt to scan the JTAG scan-path has failed. The target's JTAG scan-path appears to be broken with a stuck-at-ones or stuck-at-zero fault. (Emulation package 6.0.14.5)

    So please provide a proper solution for this.
  • Hi Akhil,

    I have assumed you are working with a custom board.

    Thoughts:

    1. Since this device has a dedicated XCLKOUT pin, I would recommend probing this signal with an oscilloscope to confirm that the device outputs a clock signal once powered.  This will confirm whether the F28335 is running or not.
      1. If XCLKOUT is not outputting a clock, I would recommend looking at the power supplies to see if they are correct.  I would also recommend checking on the XRSn pin.
      2. If XCLKOUT is outputting a clock, I would recommend probing for connectivity between the JTAG header and the device.  I might also recommend checking that pin 5 on the JTAG header (PD) is given 3.3V by your board.


    Thank you,
    Brett

  • Hai brett,

    Thanks for your reply, i am using custom board with f28335 and olimex xds 100v3. Initially in target configuration settings, the converter usage was 'generate 1149.7 4-pin standard mode'. But now i changed to 'Its bypassed,use 1149.1,mimic xds100v2' but now i getting another error, is

    The value is '-501' (0xfffffe0b).
    The title is 'SC_ERR_TEST_MEASURE'.

    Error connecting to the target:
    (Error -501 @ 0x0)
    The built-in scan-path length measurement failed.
    The built-in scan-path reliability tests cannot be
    performed without knowledge of the scan-path length.
    Try specifying the scan-path lengths in the command-line
    options or board configuration file of this utility or debugger.
    (Emulation package 5.1.232.0)


    And i checked with all other various frequencies with in given range


    And i checked XCLKOUT , and XRSn pin by giving power.

    I connected crystal across X1 and X2 and XCLKIN left unconnected.

    XCLKOUT, getting clock pulse when giviing reset to XRSn. 

    but XCLKOUT is almost 1MHz




    Thanks in Advance
    Akhil Francis

  • Hi Akhil,

    The way the chip is supposed to come up after powering is shown in the F2833x datasheet - specifically around Section 6.8.1 (Power Management and Supervisory Circuit Solutions) of the current datasheet.

    The biggest thing that concern me about your statements is that XCLKOUT seems to only be toggling when XRSn is low.  XRSn being low is when the device is held in reset.  Once the device is taken out of reset, XCLKOUT should toggle as it runs from the pre-programmed device bootloader and then onward (even if the chip hasn't been programmed yet).  

    I would recommend checking your power supplies to make sure they meet the specifications of the device datasheet.  It may also be worth looking to see what the X1/X2 waveforms look like when XRSn is no longer held high. 

    My final recommendation might be to refer to the F28335 controlCARD design.  In many circumstances it can be used as a reference - and may allow you to search for discrepancies that may lead to things that you can experiment with.  (note that the LC filtering next to the chip is not really necessary)
    \controlSUITE\development_kits\~controlCARDs\CC2833xHWdevPkg\F28335controlCARD HWDevPkg ZJZ [R2.2]\


    Thank you,
    Brett