at88sc018 ATMEL Corporation, at88sc018 Datasheet - Page 25

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

4.
5277C–CryptoCompanion–9/09
Command Execution Times
The following table lists the nominal execution times for the various commands above, subject to the assumptions
following the table.
Some of the commands take a variable amount of time based on the input parameters and/or the current state of the
AT88SC018. In general, the table below shows the worst case operational flow, subject to the list of assumptions
following the table. Actual execution time will vary from the nominal by ±25% due to variations of the internal oscillator.
This preliminary data is advisory in nature. Designs should not depend on the specific execution times below, but rather
use the standard handshake mechanisms described above. The values below are characterized on the part but are not
tested in production.
Table 51.
Assumptions:
1.
2.
3.
4.
5.
6.
VerifyFlash
Startup
ChallengeResponse
Auth_1
Auth_2
EncryptPassword
Encryption_1
Encryption_2
GrindBytes
GetRandom
IncrementCounter
ReadCounter
WriteMemory
WriteMemoryEncrypted
ReadMemory
ReadMemoryDigest
ReadManufacturingID
Lock
Clear
TWI clock assumed to be at 400 KHz.
TWI command times – 0 bytes of data ~ 75 μs. Additional byte ~ 25 μs.
VerifyFlash command is run with "Mode.Bit [1:0] = 01" case.
GrindBytes command assumes 20 bytes of data.
WriteMemory and ReadMemory commands assume 16 bytes of data.
These processing times do not include data transfer on the TWI.
Command
Nominal Execution Times
4000 μs
8000 μs
4000 μs
8000 μs
60 μs
100 μs
4100 μs
60 μs
50 μs
4000 μs
50 μs + 10 ms
50 μs
200 μs + 4 ms
4100 μs + 2 ms
200 μs
4000 μs
200 μs
8000 μs + 36 ms
5 μs
Nominal Time
(2 EE writes, if not within a page)
(1 EE write)
(18 EE write worst case)
(5 EE writes worst case)
CryptoCompanion Chip
Notes
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