AT88SC0404C-PI Atmel, AT88SC0404C-PI Datasheet - Page 24

• Manufacturer Part Number: AT88SC0404C-PI
• Manufacturer: Atmel

Specifications of AT88SC0404C-PI

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: PDIP
• Mounting: Through Hole
• Pin Count: 8
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Not Compliant

5.3.13. Session Keys (S
5.3.14. Secret Seeds (G
5.3.15. Password Sets
5.3.16. Secure Code
5.3.17. Password Attempts Counters (PAC)
5.3.18. Authentication Attempts Counters (AAC)
5.4.
5211C–SMIC–01/10
Atmel AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
Each of these fields contains a 64-bit session key for use during encryption. The internal logic modifies the session key
each time it successfully processes authentication or encryption verification. The session keys do not require initial
values and thus programming of initial values is not necessary.
Each of these fields contains a 64-bit secret seed that is used in conjunction with the corresponding cryptogram and
session key during the authentication and encryption sequences. The customer programs the secret seeds during
device personalization.
The password fields contain eight sets of two 24-bit passwords for read and write operations. The customer defines the
values of these passwords during personalization. Successfully verifying the write password allows modification of the
read and the write passwords of the same set.
The secure code is the Write 7 password. Properly presenting this password grants write access to the configuration
memory during personalization. Atmel
values after successful presentation during a verify Write 7 password operation.
codes for the various devices as they leave the Atmel factory. After blowing the PER fuse, verifying Write 7 password
no longer grant write access to the configuration memory, and the configuration memory becomes read-only thereafter.
Each of the sixteen PAC fields contains an 8-bit attempts counter for the verify password process. Each PAC
corresponds to a password. The attempts counter limits the number of incorrect consecutive presentations of the
corresponding password to four, after which it locks the password from future use. The PAC will decrement ($FF, $EE,
$CC, $88, $00) with each incorrect attempt to present the password. The PAC permanently locks the corresponding
password once its value reaches $00. Prior to reaching $00, any correct presentation of the password resets the PAC
value to $FF.
Each of the four AAC fields contains an 8-bit attempt counter for the authentication process. Each AAC field
corresponds to each authentication key set. The attempts counter limits the number of incorrect consecutive attempts
to authenticate to four, after which it locks the authentication key set from future use. The AAC will decrement ($FF,
$EE, $CC, $88, $00) with each incorrect attempt to authenticate. The AAC permanently locks the corresponding key
set once its value reaches $00. Prior to reaching $00, any correct attempt to authenticate resets the AAC value to $FF.
Security Fuses
Atmel CryptoMemory
the fuse has been blown. Bits four to seven of this byte are not used as Security Fuses and are reserved for Atmel use.
Table 21. Device Fuses
The bits, SEC, PER, CMA and FAB are non-volatile fuses blown at the end of various steps in the manufacturing and
personalization process. Once blown, these fuses can never be reset. Atmel blows the SEC fuse to lock the lot history
code before the device leaves the factory. Blowing the remainder of the fuses must follow the sequence:
resv
F
7
resv
0
0
F
-G
®
– S
6
uses four fuses. The status of these fuses is given in a ‘fuse byte.’ A value of ‘0’ indicates that
3
)
3
)
resv
F
5
®
defines the initial value of the secure code but the customer may change these
resv
F
4
SEC
F
3
PER
Table 16
F
2
on page
CMA
F
1
19,
show the secure
FAB
F
0
23