TMS320F28P650DK: XDS110 Error -2131 and SC_ERR_PATH_BROKEN (-233) – Cannot connect to target

Hi,

I am unable to connect to my target using XDS110 in CCS.

Error shown:
(Error -2131 @ 0x0) Unable to access device register.

Reset log shows:
SC_ERR_PATH_BROKEN (-233)
The JTAG IR and DR scan-paths cannot circulate bits.
Target scan-path appears broken (stuck-at-ones or zeros).

Setup:
- Device: [F28P65X]
- Board: [LaunchPad ]
- Debugger: XDS110
- CCS Version: 20.4.0
- OS: Windows 11

What I verified:
- XDS110 appears correctly in Device Manager
- Controller reset successful
- Target board powered
- Lowered TCLK to 50 kHz
- Power-cycled board and debugger

Has anyone seen this before?
What hardware checks do you recommend?

Thank you.

Hello,

This is on the P65x LaunchPad right? Please ensure that you're using full JTAG (4-pin).  Due to the isolation scheme used on the F28P65x LaunchPad, 2-pin cJTAG mode is not supported. 

Please also try putting the device in WAIT boot to eliminate application obstruction of the connection.

Best,
Matt

Hi Matt,

Thank you for the suggestion.

I am using the onboard XDS110 with the standard 4-pin JTAG connection (not 2-pin cJTAG). In CCS, the interface is configured accordingly.

However, I am still getting the same error:

SC_ERR_PATH_BROKEN (-233)
"The JTAG IR and DR scan-paths cannot circulate bits. Target scan-path appears broken (stuck-at-ones or zeros)."

I have also:

• Lowered TCLK frequency

• Power-cycled the board and debugger

• Verified the board is powered correctly

• Confirmed XDS110 is detected properly in Device Manager

Please let me know if there are any additional hardware checks you would recommend (e.g., boot mode settings, isolation jumpers, or specific signals to probe).

Thank you.

Hello,

Did you put the device in wait boot? What is the status of the XRSn signal?

Best,
Matt

Hi Matt,

Yes, I have now put the device into WAIT boot mode and retried the connection.

The XRSn signal measures 3.3 V (stable high) and is not being held low.

However, I am still seeing the same error:

IcePick_C_0: Error -2131
SC_ERR_PATH_BROKEN (-233)

Please let me know what you would recommend checking next (e.g., specific JTAG signals or isolation jumpers on the LaunchPad).

Thank you.

Hello,

Let's check out the JTAG signals (TDO, TDI, TCK, TMS) and validate that they are properly driven? 

And to understand the background of the issue, did you have issues with JTAG before? Was the DCSM OTP programmed?

Best,
Matt