at88sc018 ATMEL Corporation, at88sc018 Datasheet - Page 22

• Manufacturer Part Number: at88sc018
• Description: Cryptocompanion? Chip For Cryptomemory And Cryptorf
• Manufacturer: ATMEL Corporation

3.12.
3.13. WriteMemory
3.14.
22
ReadCounter
Returns the 32 bit current state of the specified counter. There are no read restrictions on the counters.
Table 37.
Table 38.
Writes the contents of the specified address and those following it up to the end of the read/write memory space. Prior
to locking, any byte after the lock byte can be written with this command. After the AT88SC018 has been locked, only
the read/write space can be written with this command.
The input data must always be 16 bytes long, though fewer bytes may be written into the EEPROM. While the
AT88SC018 ignores these pad bytes, Atmel recommends that they always be 0xFF.
Table 39.
Table 40.
WriteMemoryEncrypted
Writes a 16 byte page of the EEPROM, using the encryption algorithm described below. Smaller blocks of memory
cannot be written using this command.
This command cannot be run after the AT88SC018 has been locked.
Table 41.
CryptoCompanion Chip
Counter
Value
Address
Count
Data
Address
Data
Nonce
Name
Name
Name
Name
Name
Inputs
Outputs
Inputs
Outputs
Inputs
Size
Size
Size
Size
Size
16
16
16
1
4
2
1
2
Counter index to be read, must be from 0-3. The upper 4 bits of this parameter are
ignored.
Current value of counter.
Address in EEPROM of the first byte of data to be written. The most significant 7 bits are
ignored.
If 0, write 1 byte… if 0x0F, write 16 bytes. The upper 4 bits are ignored.
Clear text bytes, padded to 16 bytes total.
Address of the 16 byte page within EEPROM to which data is to be written. The least
significant 4 and most significant 7 bits are ignored.
Encrypted data
Random value used to seed encryption
Description
Description
Description
Description
Description
5277C–CryptoCompanion–9/09