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JTAG debugger can't find Vybrid core

Question asked by Sergei Poselenov on Apr 25, 2014
Latest reply on May 7, 2014 by Sergei Poselenov

Hello,

 

We are observing a problem when JTAG debugger (we are using Segger JLink) fails to connect to the VF6 core after the routine

firmware upgrade:

 

[psl@skywanderer ~]$ sudo JLinkExe

SEGGER J-Link Commander V4.78k ('?' for help)

Compiled Dec  5 2013 20:30:34

DLL version V4.78k, compiled Dec  5 2013 20:30:31

Firmware: J-Link ARM V8 compiled Nov 25 2013 19:20:08

Hardware: V8.00

S/N: 58010557

Feature(s): GDB

VTarget = 3.306V

Info: TotalIRLen = 4, IRPrint = 0x01

 

****** Error: Could not power up debug port: Control/Status register reads D0000001

No devices found on JTAG chain. Trying to find device on SWD.

Info: Found SWD-DP with ID 0x3BA02477

 

****** Error: Could not power up debug port: Control/Status register reads D0000040

Info: Found SWD-DP with ID 0x3BA02477

 

****** Error: Could not power up debug port: Control/Status register reads D0000040

No device found on SWD.

Did not find any core.

Failed to identify target. Trying again with slow (4 kHz) speed.

Info: TotalIRLen = 4, IRPrint = 0x01

 

****** Error: Could not power up debug port: Control/Status register reads D0000001

No devices found on JTAG chain. Trying to find device on SWD.

Info: Found SWD-DP with ID 0x3BA02477

 

****** Error: Could not power up debug port: Control/Status register reads D0000040

Info: Found SWD-DP with ID 0x3BA02477

 

****** Error: Could not power up debug port: Control/Status register reads D0000040

No device found on SWD.

Did not find any core.

 

Our hardware is our own System-On-Module with MVF61NN151CMK50 SOC and the firmware is a port of U-Boot loaded to the QSPI flash.

Obviously, the failing module has been re-programmed with JLink many times successfully. Also we tried another JTAG debugger (an Open OCD model) with similar results.


Whatever errors could be in hardware design or software, given the above info - what could cause the above behavior and what could be done to analyze and recover?


We already have two such modules.


Any thoughts on this would be much appreciated.


Regards,


Sergei Poselenov

 

 

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