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: 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. However, even with JTAG locked, it is still possible to program the corresponding external Flash of the ADSP21565 via JTAG. 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: 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? 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

SLA Status	Assignee	Support Status
SLA Closed. Missed after 104 hours		Awaiting Customer Response

external flash can be operated when JTAG has been locked

wuxiangzhi on Dec 16, 2025

Category: Software

Product Number: ADSP-21565

Software Version: 2.12.0

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:

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.
However, even with JTAG locked, it is still possible to program the corresponding external Flash of the ADSP21565 via JTAG.
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:

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?
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

Audio Signal Processors software emulation key 2.12.0 ADSP-21565 EXTERNAL FLASH SHARC Audio Processors/SoCs Show More

Parents

NandiniC

on Dec 18, 2025 7:30 AM
0
Hi Xiangzhi,

Yes, the ADSP-21565 does support JTAG disable feature. It is possible to restrict the JTAG on the ADSP-21565 by programming and locking the OTP.

To clarify your understanding, the term "JTAG locked" or "JTAG unlock" does not exist, you can only enable the lock bit of the processor to disable access. When the processor lock bit is not enabled, the JTAG can access the corresponding external Flash.
Also please note that once the part is locked, it can only be accessed using JTAG by providing the emulation key.
So please ensure before locking the part, a 128 bit emulation key must be programmed into the OTP secure_emu_key field using the OTP Program API.

If not already referred, we would suggest you to refer the below application notes to understand the concepts of Secure Booting.
https://www.analog.com/media/en/technical-documentation/application-notes/EE366v02.pdf
https://www.analog.com/media/en/technical-documentation/application-notes/ee447v01.pdf

The associated examples are available in the below path:
https://www.analog.com/media/en/technical-documentation/application-notes/EE366v02.zip

https://www.analog.com/media/en/technical-documentation/application-notes/ttp_bootrom.zip

Regards,
Nandini C
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wuxiangzhi on Dec 24, 2025 6:38 AM in reply to NandiniC
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Hello Nandini,

We have tried the provided examples, but we are still unable to prevent access to the external flash via JTAG.
Could you please provide a specific example for the ADSP21565, along with step-by-step instructions to test this functionality?

Thanks & Best regards,

xiangzhi wu
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NandiniC

on Dec 26, 2025 5:41 AM in reply to wuxiangzhi
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Hi,

Could you please provide more information on below points,

1.Have you generated the ECDSA-224 key pair using the CCES signtool (genkeypair command), and confirmed that both the public and private keys were created successfully in DER format?

2.Was the application loader file (.ldr) generated using the elfloader tool with the correct processor type (ADSP-21565) and boot configuration (SPI, width, boot code)?

3.Did you convert the loader file into a secure boot stream (e.g., BLp format) using adi_signtool with the correct private key, hash configuration, and attributes?

4.How was the secure boot stream programmed into the storage device, and did you follow the CLDP flashing procedure described in the below commands for ADSP-2156x BSP?

For reference, please refer the below CLDP command,

"C:\analog\cces\3.0.1\adi_signtool.exe" -proc ADSP-21569 -add-sbh-hash-256 sign -type BLp -attribute 0x80000003=256 -prikey keypair.bin -infile application.ldr -outfile application_BLp.ldr

5.Which method was used to program the security keys into OTP memory (CLDP or ROM-based OTP APIs), and was the programming verified before relying on the boot kernel to decrypt the secure boot stream during boot?

6.If not already referred, test the Secure_Openpart example code first before writing to OTP memory. Please find the below FAQ link,

Is it possible to verify Secure Booting without programming Keys into OTP Memory?

Regards,

Nandini C
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NandiniC

on Dec 26, 2025 5:41 AM in reply to wuxiangzhi
0
Hi,

Could you please provide more information on below points,

1.Have you generated the ECDSA-224 key pair using the CCES signtool (genkeypair command), and confirmed that both the public and private keys were created successfully in DER format?

2.Was the application loader file (.ldr) generated using the elfloader tool with the correct processor type (ADSP-21565) and boot configuration (SPI, width, boot code)?

3.Did you convert the loader file into a secure boot stream (e.g., BLp format) using adi_signtool with the correct private key, hash configuration, and attributes?

4.How was the secure boot stream programmed into the storage device, and did you follow the CLDP flashing procedure described in the below commands for ADSP-2156x BSP?

For reference, please refer the below CLDP command,

"C:\analog\cces\3.0.1\adi_signtool.exe" -proc ADSP-21569 -add-sbh-hash-256 sign -type BLp -attribute 0x80000003=256 -prikey keypair.bin -infile application.ldr -outfile application_BLp.ldr

5.Which method was used to program the security keys into OTP memory (CLDP or ROM-based OTP APIs), and was the programming verified before relying on the boot kernel to decrypt the secure boot stream during boot?

6.If not already referred, test the Secure_Openpart example code first before writing to OTP memory. Please find the below FAQ link,

Is it possible to verify Secure Booting without programming Keys into OTP Memory?

Regards,

Nandini C
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external flash can be operated when JTAG has been locked

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