AT88SA102S_10 ATMEL [ATMEL Corporation], AT88SA102S_10 Datasheet - Page 18

• Manufacturer Part Number: AT88SA102S_10
• Description: Atmel CryptoAuthentication
• Manufacturer: ATMEL [ATMEL Corporation]

18
To facilitate secure personalization of the AT88SA102S, this map may be encrypted before being sent to the chip.
If this mode is desired, then the Decrypt parameter should be set to one in the input parameter list. The
decryption (transport) key is computed by the GenPersonalizationKey command, which must have been run
immediately prior to the execution of BurnSecure. In this case, prior to burning any fuses, the input Map
parameter is XOR’d with the first 88 bits of that digest from the GenPersonalizationKey command. The
GenPersonalizationKey and BurnSecure commands must be run within a single Wake cycle prior to the expiration
of the watchdog timer.
The power supply pin must meet the V
fuses reliably. If V
burn time will be 250µs. If V
set to 0x8000 and the internal burn time will be 190ms per fuse bit burned. The chip does NOT internally check
the supply voltage level.
The total BurnSecure execution delay is directly proportional to the total number of fuses being burned. If V
less than 4.5V, then the total BurnSecure execution time may exceed the interval remaining before the expiration
of the watchdog timer. In this case, the BurnSecure command should be run repeatedly, with each repetition
burning only as many fuses as there is time available. The system software is responsible for counting the
number of ‘1’ bits in the clear-text version of the map parameter sent to the chip – no error is returned if the fuse
burn count is too high. Other than Fuse[87] (see below), the fuses may be burned in any order.
Prior to execution of BurnSecure, the AT88SA102S verifies that Fuse[87] is un-burned. If it has been burned, then
the BurnSecure command will return an error. Fuse[87] can either be burned during the last repetition of
BurnSecure or it can be individually burned with BurnFuse.
There are a series of very small intervals during t
power supply must not be removed during this interval and the watchdog timer must not be allowed to expire
during this interval, or the fuse may end up in a state where it reads as un-burned but cannot be burned.
Table 5-2.
Table 5-3.
Atmel AT88SA102S
Opcode
Param1
Param2
Data
Name
Success
Input Parameters
Output Parameters
Name
BURNSECURE
Decrypt
BurnTime
Map
Size
1
CC
is greater than 4.5V, then the BurnTime parameter should be set to 0x00 and the internal
Notes
Upon successful execution, a value of 0 will be returned by the Atmel AT88SA102S.
CC
Size
is less than 4.5V but greater than V
11
1
1
2
Notes
0x10
If 1, decrypt Map data before usage. If 0, the map is transmitted in plain text
Must be 0x00 00 if V
Which fuses to burn, may be encrypted
BURN
specification during the entire BurnSecure command in order to burn
EXEC_SECURE
CC
> 4.5V, must be 0x80 00 otherwise
when the fuse element is actually being burned. The
BURN
then the BurnTime parameter should be
8584F–SMEM–8/10
CC
is