AT88SC0404CA-TH Atmel, AT88SC0404CA-TH Datasheet - Page 36

• Manufacturer Part Number: AT88SC0404CA-TH
• Description: IC EEPROM 4KBIT 4MHZ 8TSSOP
• Manufacturer: Atmel
• Series: CryptoMemory®r

Specifications of AT88SC0404CA-TH

• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Memory Size: 4K (512 x 8)
• Speed: 4MHz
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8664C–CRYPT–01/10
Write Fuses
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. The SEC fuse is blown at the Atmel
Table 20. Fuse Identification
Send Checksum
To write data to user zones that require Authentication or Encryption for write access (ER = “0”, AM[1:0] = “00”, “01”, or
“10” in the access register), the host should first carry out the write command $B0. At this point the memory is
unchanged and the device is waiting for the host to provide a valid checksum before initiating the write cycle. The host
immediately sends the checksum it has computed using the System WRITE command with P1 = $02. Only if the
checksum is valid will the device initiate the write cycle. Furthermore, if the device receives an incorrect checksum, it
will clear the authentication privilege. After this command the host must perform ACK polling.
Set User Zone
Before reading and writing data in the user zones, the host must select a zone with this command. At this time the host
chooses whether anti-tearing should be active for this zone.
Table 21. Anti-Tearing
Data written to the configuration zone may be done with anti-tearing enabled by setting Address 1 to $08 of the write
configuration 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 22. System WRITE Command Detail
S
A
R
T
T
Write Config Zone with Anti-Tearing
Set User Zone with Anti-Tearing
Command
1011 0100
Fuse
CMA
SEC
PER
FAB
Command Description
C
A
K
Address 1
Fuse ID
0000 xxxx
$07
$06
$04
$00
A
C
K
Address 2
xxxx xxxx
Atmel AT88SC0104/0204/0404/0808/CA
®
factory to protect lot history information.
A
C
K
xxxx xxxx
Command
N
$B4
$B4
C
A
K
d7--- ---d0
Addr 1
Data
$0B
$08
A
C
K
Addr 2
zone
addr
Data x N
d7--- ---d0
N ≤ $08
$00
A
C
K
N
O
S
P
T
Data (N)
N-bytes
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