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Original question:

CCS/TIDA-01281: Olimex XDS100v3/TMS320F28035 - SC_ERR_PATH_BROKEN

CCS/TIDA-01281: Olimex XDS100v3/TMS320F28035 - SC_ERR_PATH_BROKEN

Thomas Albrecht46
Prodigy 240 points
Part Number: TIDA-01281

Tool/software: Code Composer Studio

Hi there,

I have to dig the old topic out again. In the meantime we've bought the xds200 from spectrum digital. Long story short. I still get the error:

The value is '-233' (0xffffff17).
The title is 'SC_ERR_PATH_BROKEN'.

The explanation is:
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.

[End: Texas Instruments XDS2xx USB Debug Probe_0]


I've also build up a second TIDA-01281 design. Same problem. I have tried CSS v5.5 , CSS6.2 and CSS 8.1. Everywhere the same problem.

So could you please check my adjustments concerning the JTAG.

Best regards,

Thomas

  • 0
    TI__Guru**** 169234 points

    Thomas,

    Interesting; I see the setting on "JTAG / cJTAG / SWD Mode" incorrect in your screenshot. It should be set to "JTAG (11491.), SWD and cJTAG are disabled". The F28035 device does not support cJTAG.

    However, the error you are seeing is definitely a HW error: it could be a problem on the JTAG circuitry or the device itself not being properly powered up.

    Looking at the TI design schematics, I see a problem: a pull up on the TDO pin that is not present in the XDS reference design rules nor in section 5.9 of the device's datasheet.

    I also don't see on the schematics the EMU0/EMU1 pins pulled up on the JTAG header (pins 13 and 14), although this is not mandatory for this particular device that does not have these pins. 

    I will try to think about any additional details and report back. I will also see if a device expert may be able to comment further on any other potential pitfalls from a device perspective. 

    Regards,

    Rafael

  • 0 in reply to desouza
    Prodigy 240 points

    Hi Rafael,

    you kind of did it! I took a look at the schematic again and the net labels. But TDO and TMS didnt fit to the according pin of the Microcontroller. What I want to say is, that TMS and TDO are swapped. So I swapped them according to the labels of the Microcontroller and now it's working.

    I don't know whether it makes sense to add this to the other thread as a fix. It would be nice if this maybe gets added to an errata of the Tida-01281 if you can confirm this.

    Thank you very much

    Best regards

    Thomas

  • 0 in reply to Thomas Albrecht46
    TI__Guru**** 169234 points

    Thomas,

    Thanks for reporting back your findings and good catch on the crossed nets. I contacted the authors of this TI Design to confirm the issue.

    I also posted a note on the other thread pointing to this one.

    Regards,
    Rafael