ATSHA204 ATMEL [ATMEL Corporation], ATSHA204 Datasheet - Page 49

• Manufacturer Part Number: ATSHA204
• Description: Atmel CryptoAuthentication
• Manufacturer: ATMEL [ATMEL Corporation]

Upon completion of the command, TempKey.SourceFlag is set to “Rand.”
If Mode[0:1] is three, this command operates in pass-through mode, the input parameter (NumIn) must be 32 bytes long, and
TempKey is loaded with NumIn. No SHA-256 calculation is performed, no data is returned to the system, and
TempKey.SourceFlag is set to “Input.”
If Mode[0:1] is one, the automatic seed update is suppressed. See Section 3.4.2 for more details.
Table 8-27. Mode Encoding
Bits
2-7
0-1
Meaning
Must be zero.
0: Combine new random number with NumIn, store in TempKey. Automatically update EEPROM seed only if
1: Combine new random number with NumIn, store in TempKey. Generate random number using existing
2: Invalid
3: Operate in pass-through mode and write TempKey with NumIn.
necessary prior to random number generation. Recommended for highest security.
EEPROM seed, do NOT update EEPROM seed.
Atmel ATSHA204 [DATASHEET]
8740D−CRYPTO−3/12
49