[TrouSerS-users] engraved chip version and tpm_version output differ

[Ismaël FEZZAZ]

Hi,

I am working on an arm embeded system with an i2c wired tpm chip:
Linux v2r1 3.14.36ltsi-yocto-standard #12 Tue Sep 15 11:57:15 CEST
2015 armv7l GNU/Linux

The tpm_version output:
TPM 1.2 Version Info:
Chip Version: 1.2.66.4
Spec Level: 2
Errata Revision: 3
TPM Vendor ID: ATML
TPM Version: 01010000
Manufacturer Info: 41544d4c

But the version engraved on the chip is 1.2.42.4
The complet label on chip is
SC323205T
1528 A3BU7A
1.2.42.04 U PH

My question is why is there a difference between the two ?
Thanks.

--
Ismael

[Thomas, Ronnie L.]

Hi Ismael,
The "Chip Version:" 66 returns the decimal equivalent of the Atmel firmware version which is the hex value "42".

Ronnie Thomas
Senior Software Development Engineer-TPM/Atmel Corporation
1150 E. Cheyenne Mountain Blvd, Colorado Springs, CO 80906
Tel:[phone]/Fax:[phone]
***@atmel.com/ http://www.atmel.com/

-----Original Message-----
From: Ismaël FEZZAZ [mailto:***@gmail.com]
Sent: Thursday, September 24, 2015 8:35 AM
To: trousers-***@lists.sourceforge.net
Subject: [TrouSerS-users] engraved chip version and tpm_version output differ

Hi,

I am working on an arm embeded system with an i2c wired tpm chip:
Linux v2r1 3.14.36ltsi-yocto-standard #12 Tue Sep 15 11:57:15 CEST
2015 armv7l GNU/Linux

The tpm_version output:
TPM 1.2 Version Info:
Chip Version: 1.2.66.4
Spec Level: 2
Errata Revision: 3
TPM Vendor ID: ATML
TPM Version: 01010000
Manufacturer Info: 41544d4c

But the version engraved on the chip is 1.2.42.4 The complet label on chip is SC323205T
1528 A3BU7A
1.2.42.04 U PH

My question is why is there a difference between the two ?
Thanks.

--
Ismael

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[Ismaël FEZZAZ]

Post by Thomas, Ronnie L.
The "Chip Version:" 66 returns the decimal equivalent of the Atmel firmware version which is the hex value "42".

Thanks for the answer !

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[Ken Goldman]

In addition to Ronnie's authoritative answer, keep in mind that many
TPMs have a "field upgrade" capability. So, while the part may have
come out of manufacturing with one firmware revision, the firmware may
have been updated later.

To me, the getcapability response is more trusted than whatever is
inscribed on the plastic.



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