AT88SC0104CA_11 ATMEL [ATMEL Corporation], AT88SC0104CA_11 Datasheet - Page 47

• Manufacturer Part Number: AT88SC0104CA_11
• Description: Atmel CryptoMemory Specification Datasheet
• Manufacturer: ATMEL [ATMEL Corporation]

10.4
10.5
10.5.1 Functional
T=0 Command Descriptions
The command set of CryptoMemory is expanded compared to a Serial EEPROM as the functionality of CryptoMemory
exceeds that of a simple memory device. Each instruction sent to the CryptoMemory must have four bytes: Command,
Address 1, Address 2, and N. The last byte, N, defines the number of any additional data bytes to be sent or received from the
CryptoMemory device.
Write User Zone: $B0
Figure 10-2. Write User Zone Command Functional Description
The write user zone command $B0 allows writing of data into the device's currently selected user zone (the procedure for
selecting a user zone is described below.
The maximum numbers of bytes that may be written in a single write operation is $10 and corresponds to the EEPROM page
size. Each data byte within a page must only be loaded once. In anti-tearing mode the maximum value for N is $08 for all
devices. A write in anti-tearing mode is activated with the set user zone command with the anti-tearing option (00 B4 0B zz
00); all subsequent writes to the user zone will be in anti-tearing mode.
"When a write user zone command is sent in authentication mode or encryption mode the data is saved in a buffer until a
cryptographic checksum is received. The host must send the checksum it has computed immediately after the write user zone
command. If the checksum is valid, CryptoMemory writes the data; if the checksum is incorrect the data is discarded and the
cryptographic engine is reset."
If the host is not allowed to write in the zone, the device will return the "Command Unauthorized" code ($69 $00) after it has
received the P3 byte.
Table 10-3. Write User Zone Command Structure
N data bytes
CLA
**
INS : Command
Host
Command
Address A1
Address A2
Number of bytes N
Data
…
Data
$B0
P1 : Address 1
Command Header
0000 0000
Device
Atmel AT88SC0104CA/0204CA/0404CA/0808CA [Datasheet]
P2 : Address 2
0a
6
-- ---a
0
000n
P3 : N
4
--- n
0
d
Data(1)
7
--- ---d
0
8664E−CRYPTO−12/11
Data Sent
...
...
d
Data(N)
7
--- ---d
0
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