![](http://datasheet.mmic.net.cn/Atmel/AT88SA102S-TH-T_datasheet_96438/AT88SA102S-TH-T_3.png)
3
1.2
Memory Resources
Fuse
Block of 128-fuse bits that can be written through the one wire interface. Fuse[1] and Fuse[87] have
special meanings, see Section
1.3 for more details. Fuse[88:95] are part of the manufacturing ID value
fixed by Atmel. Fuse[96:127] are part of the serial number programmed by Atmel which is guaranteed to
be unique. See Section
1.4 for more details on the Manufacturing ID and Serial Number.
ROM
Metal mask programmed memory. Unrestricted reads are permitted on the first 64-bits of this array. The
physical ROM will be larger and will contain other information that cannot be read.
ROM MfrID
2-bytes of ROM that specifies part of the manufacturing ID code. This value is assigned by Atmel and is
always the same for all chips of a particular model number. For the AT88SA102S, this value is 0x2301
(appears on the bus: 0x0123), ROM MfrID can be read by accessing ROM bytes 0 and 1 of Address 0.
ROM SN
2-bytes of ROM that can be used to identify chips among others on the wafer. These bits reduce the
number of fuses necessary to construct a unique serial number. The ROM SN is read by accessing
ROM bytes 2 and 3 of Address 0. ROM SN can always be read by the system and is optionally included
in the message digested by the MAC command.
RevNum
4-bytes of ROM that are used by Atmel to identify the model mask and/or design revision of the
AT88SA102S chip. These bytes can be freely read as the four bytes returned ROM address one,
however system code should not depend on this value as it may change from time to time.
1.3
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 one when shipped
from the Atmel factory and transition to a zero when they are burned. Bits 0-63 can never be read, while bits 64-128 can
always be read.
Table 1-1.
The 128 Fuses in the Atmel AT88SA102S Chip are Arranged in the Following Manner
Fuse #
Name
Description
1
BurnFuse Enable
If this fuse is one, then the BurnFuse command is enabled. If it is burned to zero, then
the BurnFuse command is disabled.
0 and 2
63
Secret Fuses
These fuses can be securely written by the BurnSecure command but can never be
read directly with the Read command.
64
83
Status Fuses
These fuses can be written with the BurnSecure command and can always be read
with the Read command. They are totally user-defined.
84
86
Status Fuses
These fuses can be written with the BurnSecure command and can always be read
with the Read command. They are user-defined, but have special significance for the
Pause Long command. See Section
6.6.87
Fuse Disable
The MAC command ignores the values of Fuse[0-86] while this fuse is an one
Once it is burned to zero, the BurnSecure command is disabled.
88
95
Fuse MfrID
See Section
1.4. Set by Atmel; cannot be modified in the field.
96
127
Fuse SN
See Section
1.4. Set by Atmel; cannot be modified in the field.
BurnFuse Enable
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.