at88sc0104c ATMEL Corporation, at88sc0104c Datasheet - Page 35

• Manufacturer Part Number: at88sc0104c
• Description: Cryptomemory Specification For Standard Mode Of Operation
• Manufacturer: ATMEL Corporation

7.6.3.3
7.6.3.4
5210A–SMIC–04/07
Write Fuses
Set User Zone
The fuses may only be "programmed", that is written from '1' to '0'. The write fuses operation is
allowed only after successfully presenting the secure code (write 7 password). The fuses must
be blown sequentially: FAB must be blown first, CMA may be blown only if FAB is ‘0’, and PER
only if CMA is ‘0’. After this command the host must perform ACK polling.
Table 7-4.
Before reading and writing data in the user zones, the host must select a zone with this com-
mand. At this time the host chooses whether anti-tearing should be active for this zone.
Table 7-5.
Data written to the configuration memory may be done with anti-tearing enabled by setting
address 1 to $08 of the Write Config Zone command.
To enable anti-tearing for writes to a user zone a Set User Zone command is executed with
address 1 set to $0B. All subsequent Write User Zone commands will be executed with anti-
tearing enabled until the next Set User Zone command. Anti-tearing should be turned off if not
required, as it would otherwise cause more write cycles than necessary.
Figure 7-8.
Command Description
Write Config Zone with Anti-Tearing
Set User Zone with Anti-Tearing
S
A
R
T
T
Fuse
Command
CMA
PER
FAB
1011 0100
AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
Fuse Writing
Anti-Tearing
System Write
A
C
K
Fuse ID
Address 1
$06
$04
$00
0000 xxxx
A
C
K
Address 2
xxxx xxxx
Command
$B4
$B4
A
C
K
xxxx xxxx
Addr 1
N
$0B
$08
A
C
K
Addr 2
d7--- ---d0
zone
addr
Data
A
C
K
N ≤ $08
$00
Data x N
N
d7--- ---d0
Data (N)
N bytes
C
A
K
O
S
T
P
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