What is the reason for downloading HSM first during firmware download?

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taegyunahn
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Hello.

I'm using Traveo II CYT2B93x.

I download a total of three firmware files (HSM, FBL, APP) onto the CYT2B93x MCU using Miniprog4, where HSM file is downloaded to the CM0P core and FBL & APP file are downloaded to the CM4 core.

 

I understand that HSM firmware needs to be downloaded first, but could you explain the reason behind it?

In the case of other MCUs, downloading the HSM firmware first can cause problems, so they download the HSM firmware last. Is there no issue related to the download order of HSM firmware in Traveo II?

 

Thank you.

MSV.

 

 

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Kavya_B
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Hello @taegyunahn ,

In general, I don't think there is a rule on the order with which you flash the SW for M0+ and CM4/CM7 cores, as far as you flash all the SWs properly without missing any.

If you would like to confirm with your specific system/project use case, you may give more details (for example, if you have separate elf/hex files and dependency eg. authentication etc.?)

 

Thanks,

Kavya

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Kavya_B
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Hello @taegyunahn ,

In Traveo II controllers, only CM0+ core application is launched by boot. Please refer to 'Flash Boot' chapter in Architecture TRM for more details/understanding. After CM0+ application is launched by flash boot, the SW running on CM0+ core is supposed to enable the application cores (CM4/CM7 cores) and launch the respective applications on these cores. You will see the similar implementation in any examples of Traveo II Sample Driver Library.

I think this could be the basic reason to have the CM0+ SW (in your case the HSM firmware) flashed first. Without a valid firmware running on CM0+ core, the application cores might not be enabled even though the corresponding firmware is flashed.

 

Thanks,

Kavya

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taegyunahn
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The hardware security module (HSM) firmware file downloaded to the CM0P core appears to work normally when downloaded to Flash for the last time, not the first time.

Does the sequence of downloading firmware files to Flash not matter?

 

Thank you.

MSV.

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Kavya_B
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10 likes given 25 solutions authored 5 likes given

Hello @taegyunahn ,

In general, I don't think there is a rule on the order with which you flash the SW for M0+ and CM4/CM7 cores, as far as you flash all the SWs properly without missing any.

If you would like to confirm with your specific system/project use case, you may give more details (for example, if you have separate elf/hex files and dependency eg. authentication etc.?)

 

Thanks,

Kavya

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