AT88SA102S-TH-T Atmel, AT88SA102S-TH-T Datasheet - Page 3

• Manufacturer Part Number: AT88SA102S-TH-T
• Manufacturer: Atmel

Specifications of AT88SA102S-TH-T

• Lead Free Status / RoHS Status: Supplier Unconfirmed

1.3.
8584D–SMEM–5/10
Fuse Map
The AT88SA102S incorporates 128 one-time fuses within the chip. Once burned, there is no way to reset the value of a
fuse. Fuses, with the exception of the manufacturer ID and serial number bits initialized by Atmel, have a value of 1
when shipped from the Atmel factory and transition to a 0 when they are burned. Bits 0-63 can never be read, while bits
64-128 can always be read.
Table 1.
BurnFuse Enable
Secret Fuses
Status Fuses
1
0 & 2  63
64  86
87
88  95
96  127
Fuse #
The 128 fuses in the AT88SA102S chip are arranged in the following manner:
BurnFuse Enable
Secret Fuses
Status Fuses
Fuse Disable
Fuse MfrID
Fuse SN
Name
This fuse is used to prevent operation of the BurnFuse command in the application. This
fuse may only be burned to 0 using the BurnSecure command.
These 63 fuses are used to augment the keys stored elsewhere in the chip. Knowledge of
both the internally stored keys and the values of the Secret Fuses is required to generate
the correct response to the Cryptographic command of the AT88SA102S. An arbitrary
selection of these fuses is burned during personalization via the BurnSecure command.
Within this document, “Secret Fuses” is used to refer to the entire array of 64 bits: Fuse[0-
63], even though the value of Fuse[1] is fixed for most applications and its value can be
derived from the operation of the chip.
These 23 fuses can be used to store information which is not secret, as their value can
always be determined using the Read command. They can be written at the same time as
the secret fuses using the BurnSecure command, or they can be individually burned at a
later time with the BurnFuse command. Two common usage models for these fuses are:
1.
2.
Within this document, “Status Fuses” is used to refer to the entire array of 24 bits: Fuse[64-
87], even though the value of Fuse[87] is fixed after personalization and cannot be modified
in the field.
Calibration or model number information. In this situation, the 23 bits are written at the
factory. This method can also be used for feature enabling. In this case, the BurnFuse
command should not be run in the field, and the BurnFuse Enable bit should be a 0.
Consumption logging, i.e. burn one bit after every n uses, the host system keeps track
of the number of uses so far for this serial number. In this case, the BurnFuse
command is necessary to individually burn one of these 23 bits, and the BurnFuse
Enable bit should be a 1.
If this fuse is a 1, then the BurnFuse command is enabled. If it is burned to 0,
then the BurnFuse command is disabled.
These fuses can be securely written by the BurnSecure command but can
never be read directly with the Read command.
These fuses can be written with the BurnSecure command and can always be
read with the Read command.
The MAC command ignores the values of Fuse[0-86] while this fuse is a 1.
Once it is burned to 0, the BurnSecure command is disabled.
See Section 1.4. Set by Atmel, can’t be modified in the field.
See Section 1.4. Set by Atmel, can’t be modified in the field.
Description
AT88SA102S
3