AT88SC018 Datasheet, PDF (6/33 Pages) ATMEL Corporation – CryptoCompanion™ Chip for CryptoMemory and CryptoRF

1.4.5.1. Command Input
Table 3. Command Input Byte Sequence
Byte # Direction Name
Description
0
To Slave Device This byte selects a particular chip on the two wire bus. Bit 1 of this byte should be 0 to
Address indicate a command transfer to the AT88SC018. Bit 0 of this byte should be 0 to
indicate that the data bytes travel from the master to the slave (TWI write).
1
To Slave Cmd
The ordinal of the command to be executed by the AT88SC018, from the table below.
2
To Slave Size
The total number of bytes to follow this byte may be 0 in the case that there are no
operand bytes.
3, … To Slave Data
Operand bytes as specified in Command Descriptions.
If the command ordinal is legal, the AT88SC018 will ACK the command input and start processing. It takes a variable
amount of time to process the command, up to 20ms depending on the number of EEPROM pages to be written. If an
illegal command ordinal (≥0x15) is sent to the chip it will lock up for a “security delay”, then resume normal operation.
Refer to Section 1.6.4.
Values in the Cmd byte are chosen from the table below:
Table 4. Cmd Byte Values
Command Value
VerifyFlash 0x01
Startup 0x02
ChallengeResponse 0x03
Auth_1 0x04
Auth_2 0x05
EncryptPassword 0x06
Encryption_1 0x07
Encryption_2 0x08
GrindBytes 0x09
GetRandom 0x0A
IncrementCounter 0x0B
ReadCounter 0x0C
WriteMemory 0x0D
WriteMemoryEncrypted 0x0E
WriteMemoryAuthorized 0x0F
ReadMemory 0x10
ReadMemoryDigest 0x11
ReadManufacturingID 0x12
Lock 0x13
Clear 0x14
Crunch 0x15
6 CryptoCompanion Chip
5277C–CryptoCompanion–9/09