AT88SC0404C ATMEL Corporation, AT88SC0404C Datasheet - Page 3

• Manufacturer Part Number: AT88SC0404C
• Description: CryptoMemory 4 Kbit
• Manufacturer: ATMEL Corporation

Serial Data (SDA/IO)
Reset (RST)
Device Architecture
User Zones
Control Logic
2023ES–SMEM–07/04
The SDA pin is bidirectional for serial data transfer. This pin is open-drain driven and
may be wired with any number of other open drain or open collector devices. An exter-
nal pull-up resistor should be connected between SDA and V
resistor and the system capacitance loading the SDA bus will determine the rise time of
SDA. This rise time will determine the maximum frequency during read operations. Low
value pull-up resistors will allow higher frequency operations while drawing higher aver-
age power supply current.
The AT88SC0404C provides an ISO 7816-3 compliant asynchronous answer to reset
sequence. When the reset sequence is activated, the device will output the data pro-
grammed into the 64-bit answer-to-reset register. An internal pull-up on the RST input
pad allows the device to be used in synchronous mode without bonding RST. The
AT88SC0404C does not support the synchronous answer-to-reset sequence.
The EEPROM user memory is divided into 4 zones of 1024 bits each. Multiple zones
allow for different types of data or files to be stored in different zones. Access to the user
zones is allowed only after security requirements have been met. These security
requirements are defined by the user during the personalization of the device in the con-
figuration zone. If the same security requirements are selected for multiple zones, then
these zones may effectively be accessed as one larger zone.
Table 2. User Zones
Access to the user zones occurs only through the control logic built into the device. This
logic is configurable through access registers, key registers and keys programmed into
the configuration zone during device personalization. Also implemented in the control
logic is a cryptographic engine for performing the various higher-level security functions
of the device.
User 0
User 1
User 2
User 3
ZONE
$0
$1
$2
$3
128 bytes
128 bytes
128 bytes
128 bytes
$4
$5
AT88SC0404C
CC
$6
. The value of this
$7
$000
$078
$000
$078
$000
$078
$000
$078
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