external flash can be operated when JTAG has been locked

Hello Support Team Guys,

We follow the link of "Emulation Key Disable - Q&A - ADSP-2156x - EngineerZone" for JTAG locking. Regarding the JTAG key protection of ADSP-21565, we hereby feedback our test and verification results, and have 2 questions that require your company’s response.

Regarding the issue of JTAG key protection for the ADSP21565, here is the feedback on the test verification results from our side:

1. According to the previous document "EmulationKeyDisable - Copy.zip," the current test results indicate that JTAG can be locked, and debugging via JTAG is indeed prevented.
2. However, even with JTAG locked, it is still possible to program the corresponding external Flash of the ADSP21565 via JTAG.
3. The method described in the "EmulationKeyDisable - Copy.zip" file for unlocking the JTAG interface by importing an XML file has not been successfully implemented by our team so far.

two questions:

1. We are currently puzzled because the JTAG key protection function for the ADSP21565 has not been successfully implemented. Is our approach incorrect, or does the ADSP21565 DSP chip itself not yet support this feature?
2. please clarify whether the ADSP21565 DSP can indeed implement JTAG key protection—specifically, whether JTAG can be locked to prevent programming the corresponding external Flash data via JTAG after locking, while still allowing unlocking via a key.

Thanks & Best regards,

xiangzhi wu

xiangzhi wu