ATECC508A datasheet(27/109 Pages) MICROCHIP

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Name

Length

Description

NoMacFlag

1 bit

0 = The contents of TempKey were generated and can be used with any of the

MAC commands.

1 = The contents of TempKey were generated using the value in a slot for which

SlotConfig.NoMac is one, and therefore cannot be used by the MAC and

HMAC commands. If multiple slots were used in the calculation of TempKey,

then this bit will be set if SlotConfig.NoMac was set for any of those slots.

Also cannot be used with the SHA command in HMAC mode.

Valid

1 bit

0 =

The information in TempKey is invalid.

1 =

The information in TempKey is valid.

In this specification, TempKey refers to the contents of the 256-bit data register. The remaining bit fields

are referred to as TempKey.SourceFlag, TempKey.GenDigData, and so forth.

The TempKey.Valid bit is cleared to zero during power-up, sleep, brown-out, watchdog expiration, or

tamper detection. The contents of TempKey are retained when the device enters idle mode. Depending

upon the command and the circumstances, the TempKey.Valid bit is also cleared as follows:

•

Nonce, GenKey, or GenDig Commands:

TempKey.Valid will be cleared on any error other than CRC (communications) or ECC (retry).

•

CheckMac Command:

TempKey.Valid will be cleared unless a successful copy takes place (Section Password Checking).

•

Info Command:

TempKey.Valid is not modified regardless of success or failure.

•

All Others:

TempKey.Valid will be cleared for all return codes (including success) other than CRC

(communications) or ECC (retry).

ATECC508A

Device Organization

Datasheet Complete

DS20005927A-page 27

ATECC508A Datasheet(PDF) 27 Page - Microchip Technology