AT88SC0104CA_11 ATMEL [ATMEL Corporation], AT88SC0104CA_11 Datasheet - Page 31

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AT88SC0104CA_11

Manufacturer Part Number
AT88SC0104CA_11
Description
Atmel CryptoMemory Specification Datasheet
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
8.7
8.7.1
Write User Zone: $B0
Functional
Figure 8-5. Write User Zone Command Functional Description
The write user zone command $B0 allows writing of data in the device's currently selected user zone (the procedure for
selecting a user zone is described below, see Section 8.10 System Write: $B4).
The data byte address to be written is defined by Address 1 and Address 2 in the command. The value N defines how many
bytes are to be written. The maximum number of bytes that may be written is $10 corresponding to the EEPROM page size. 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 with anti-tearing command; all subsequent write operations to the user zone will be in anti-tearing mode. A write may be
started in the middle of an EEPROM page but should not extend past the end of the page.
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 not acknowledge the N byte. After
this command the host must perform ACK polling.
Figure 8-6. Write User Zone Command Structure
S
A
R
T
T
N data bytes
Command
1011 0000
C
A
K
Host
Command
Address 1
Address 2
Number of bytes N
Data
Data
Address 1
xxxx xxxx
A
C
K
Address 2
xxxx xxxx
Device
Atmel AT88SC0104CA/0204CA/0404CA/0808CA [Datasheet]
C
A
K
xxxx xxxx
N
A
C
K
d7--- ---d0
Data
A
C
K
Data x N
d7--- ---d0
A
C
K
8664E−CRYPTO−12/11
O
S
T
P
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