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Renesas India - Knowledgebase

Causes for JTAG Debugger Errors

Last Updated:09/27/2017


I can no longer connect to the JTAG debugger, what could be the cause?


There is the possibility that the TDI and TDO pins of the JTAG interface are used as general I/O ports.  If port 3 is set as a general I/O port by the software, JTAG communication cannot be performed.  If this is the case, modify your software to keep port 3 as TDI and TDO pins. 

While it is possible to use TDI and TDO pins as a general I/O port when debug mode is set as SWD (Serial Wire Debug) mode, the debug environment must support the SWD interface.

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