AT88SC0404C(2008) 查看數據表（PDF） - Atmel Corporation

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AT88SC0404C
(Rev.:2008)

CryptoMemory Specification For Standard Mode of Operation

Atmel Corporation 

AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C

3. Pin Description

3.1 Supply Voltage (VCC)

The VCC input is a 2.7V to 5.5V positive voltage supplied by the host.

3.2 Clock (SCL/CLK)

In the asynchronous T=0 protocol, the SCL/CLK input is used to provide the device with a carrier

frequency f. The nominal length of one bit emitted on I/O is defined as an "elementary time unit"

(etu) and is equal to 372/f. When the synchronous protocol is used, the SCL/CLK input is used

to clock data in on the positive clock edge and clock data out on the negative clock edge.

3.3 Serial Data (SDA/IO)

The SDA pin is bi-directional 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 external pull up resistor

should be connected between SDA and VCC, a nominal value of 4.7K ohm may be used. The

value of this 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 average

power supply current.

3.4 Reset (RST)

CryptoMemory provides an ISO 7816-3 compliant asynchronous answer-to-reset sequence.

When the reset sequence is activated, the device will output the data programmed into the 64-bit

answer-to-reset register. When RST is low, all internal logic, access-rights, and write cycles are

in reset, except the asynchronous mode activation flag. A weak internal pull-up on the RST

input pad allows the device to be used in synchronous mode without bonding RST. For synchro-

nous only smart card applications, an external pull-up on RST is recommended to ensure

synchronous operation under any system timings or conditions. CryptoMemory does not sup-

port a synchronous answer-to-reset sequence. The RST input is not available in the plastic

package options for CryptoMemory.

4. Detailed Description

To enable the security features of CryptoMemory, personalize the device by setting up registers

and loading appropriate passwords and keys. Do this by programming the configuration memory

using simple write and read commands. Gain access to the configuration memory by success-

fully presenting the secure code (write 7 password). After writing and verifying data in the

configuration memory, blow the security fuses to lock this information in the device. For addi-

tional information on personalizing CryptoMemory, please see the examples in the protocol

sections of this specification.

4.1 User Memory

The EEPROM user memory is divided into 4, 8 or 16 user zones. Multiple zones allow for the

storage of different data types or files in different zones. Access to user zones is possible only

after meeting security requirements. The customer defines these security requirements in the

configuration memory during device personalization. When the same security requirements

define access to multiple zones, the zones effectively serve as one large storage area albeit with

the requirement to select each zone prior to acces..

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5210B–SMIC–11/08

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