LAUNCHXL2-570LC43: Issue using External Debugger (XDS110) on LAUNCHXL2-570LC43

Hi Radha Kishan Sharma,

Here's what we know and what you should consider:

1. JTAG Connection Type and Isolation:

• Your setup using XDS110 External Debugger with the 14-pin JTAG header (J18) is correct in principle. However, there are some important considerations regarding isolation:
• The error you're seeing (Error -2131) is often related to device register access issues, which can be caused by improper isolation or power sequencing(0).

2. Power Supply and Isolation:

• You've correctly provided 3.3V external power to J1 pin 1 and verified VTRef
• While you've successfully isolated the onboard debugger, there might be additional isolation requirements:
• For proper isolation when using external debugging, you need to ensure proper isolation between the debugger and target(1)
• The fact that you're getting VTRef reading of 3.3V is good, but the issue might be related to the bi-directional nature of some JTAG signals(3)

3. Recommendations:

4. Check JTAG Configuration:

   • Verify that all JTAG connections are properly made and secure
   • Consider lowering the TCLK frequency in CCS as this can help with connection stability(0)

5. Power Sequencing:

   • Ensure proper power sequencing of your setup
   • Try power cycling both the debugger and the board completely
   • Make sure all ground connections are solid between the debugger and target

6. Isolation Considerations:

   • Since you're using external debugging, ensure proper isolation of all JTAG signals
   • The bi-directional signals (like TMS in cJTAG mode) require special consideration for isolation(1,3)

7. Additional Troubleshooting Steps:

   • Try resetting the emulator before connecting
   • Verify that no other debug sessions are active
   • Check for any physical damage to the connector pins
   • Consider checking the signal integrity of the JTAG lines with an oscilloscope if possible(5)

Regarding your specific question about isolating the voltage regulator:

• While isolating the voltage regulator might help in some cases, the primary issue is more likely related to proper JTAG signal isolation and power sequencing
• The fact that providing 5V DC through the optional jack didn't help suggests that the issue is not primarily power-related but more likely related to the debug interface isolation or configuration

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Thanks & regards,
Jagadish.

Hello Jagadish Gundavarapu,

Thank you for your response.

As per your recommendations, we have followed the JTAG connection standards:

1. We are getting VTref = 3.3V, indicating that the onboard debugger has been successfully isolated.

2. We have already tried lowering TCLK in CCS, but it did not resolve the issue.

We have a few follow-up questions:

1. You mentioned power cycling both the debugger and the board completely — could you tell us how to do this?

2. Regarding bi-directional signals (like TMS in cJTAG mode) requiring special consideration for isolation, which signals specifically require that and what are the steps for it?

3. We have not attempted isolating the onboard voltage regulator as we are unsure how to do it. How should we approach this (I think this could be the main reason)?

Except for the points mentioned above, we have followed all other recommendations but are still facing the same issue.

Thanks & regards,
Radha Kishan Sharma

Hi Radha Krishna,

Apologies for the delayed response!

The error is typically caused by either:

1. Hardware failure on the board
2. Invalid code in the MCU flash causing continuous resets

To resolve this issue, try the following procedure:

1. First attempt this reset procedure:

   • Open the target configuration window in CCS
   • Launch the selected configuration
   • Switch to debug window
   • Press and hold the reset (nRST) button (not PORST)
   • Click "Connect Target" immediately after releasing the nRST button
   • You may need to try this sequence multiple times

2. Important notes:

   • Use the RESET button, not the PORST button
   • Make sure all power supply LEDs are properly lit on the board
   • Do not attempt to give manual pulses to nRESET pin as this can cause problems with debugger connection

3. If the issue persists:

   • Verify all power supplies are generating properly
   • Power cycle the board
   • Try lowering the TCLK frequency in the debugger settings
   • Check for proper physical connections

The solution has been proven to work in multiple cases, though it may take several attempts to successfully connect. If the problem continues after multiple attempts, it could indicate a more serious hardware issue with the board.

Additional Tips:

• Ensure you're using the correct target configuration for the XDS110 debugger
• Verify that the board is receiving proper power supply
• If possible, try a different USB port or cable
• Make sure you have the latest CCS and emulation package installed

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Thanks & regards,
Jagadish.