AT88SC0104CA_08 Datasheet, PDF (46/58 Pages) ATMEL Corporation – CryptoMemory Specification for Standard Mode of Operation

AT88SCXXXXCA
9.4.3 System WRITE: $B4
9.4.3.1
Functional
Figure 9-5. System Write Command Functional Description
Host
Device
N data bytes
Command
Parameter P1
Parameter P2
Number of bytes N
Data
...
Data
The System Write command allows writing of system data to the device. Depending on the value
of the P1 parameter, the host may write data in the configuration zone program the fuses or set
the user zone.
Table 9-3. System Write Command Detail
Command
CLA
INS
P1
Write Config Zone
$00
$B4
$00
Write Fuses
$00
$B4
$01
Send Checksum
$00
$B4
$02
Set User Zone
$00
$B4
$03
P2
addr
fuse ID
$00
zone
P3
N ≤$10
$00
$02
$00
Data (N)
N bytes
2 bytes
The anti-tearing function is controlled by P1: the host may choose to write in the configuration
zone with anti-tearing enabled by setting P1 = $08 instead of $00. Similarly, the host may
choose to activate anti-tearing for a user zone by carrying out the Set User Zone command with
P1 = $0B instead of $03. All subsequent Write User Zone commands are then carried out 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.
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5221A–CRYPT–10/08