ATAES132-SH-ER Atmel, ATAES132-SH-ER Datasheet - Page 9

• Manufacturer Part Number: ATAES132-SH-ER
• Description: EEPROM AES 32Kbit EE I2C
• Manufacturer: Atmel

Specifications of ATAES132-SH-ER

• Rohs: yes
• Maximum Clock Frequency: 1 MHz
• Operating Supply Voltage: 6 V
• Maximum Operating Temperature: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-8
• Interface Type: I2C
• Factory Pack Quantity: 2300

2.
2.1.
2.1.1.
2.2.
2.3.
Memory
The ATAES132 EEPROM is a nonvolatile memory which is divided into several sections, with each section having a different
function. The user memory section contains 32Kbits for data storage. The configuration memory section contains the
configuration information, security control registers, and counters. The key memory stores the sixteen secret keys used to
perform cryptographic functions. The EEPROM page length is 32 bytes. The ATAES132 SRAM buffers and registers are
located near the top of the memory address space, and are accessed using the standard EEPROM read/write commands.
The complete memory map is shown in Appendix B. Each portion of the memory is described briefly in the following sections.
User Memory
The 32Kbit user memory is organized as 16 user zones of 2Kbits each. Each user zone has an associated user zone
configuration register in the configuration memory. A user zone can only be accessed when the security requirements
specified in the associated user zone configuration register have been satisfied. All bytes within a user zone have the same
access restrictions. Since the user zone access restrictions are independently configured, the security requirements for each
user zone can be unique. Any key can be used with any user zone.
Each user zone can be configured to require authentication, read encryption, write encryption, a combination of these, or no
security. The user memory can be accessed directly with standard SPI or I
or read-only access. If the user zone security is activated, then the extended ATAES132 command set is used to access the
contents of a user zone.
Automatic Post-Write Data Verification
The write and EncWrite commands include an automatic data verification function. After the EEPROM write is complete, the
data verification logic reads the new EEPROM contents and compares it to the data received from the host. If the data does
not match the ATAES132 sets the EERR bit in the STATUS register and returns a DataMatch error code. If the data is correct,
then the ReturnCode indicates success.
Key Memory
The Key Memory securely stores 16 keys which are each 128 bits long. Each key has an associated key configuration
register in the configuration memory. Keys can only be used for the cryptographic functions enabled in the key configuration
register. Individual keys can be configured to require a successful authentication prior to use. Key values can never be read
from the ATAES132 under any circumstances. See Appendix F for the key memory map.
The key memory can be written prior to locking with either encrypted or cleartext data. Encrypted writes are performed using
the EncWrite command (see Section 7.11). Cleartext writes are performed using the standard SPI or I
Section 5.3). After locking, the key registers are managed with the KeyCompute, KeyExport, KeyImport, KeyLoad, and
KeyTransfer commands. The KeyTransfer command allows the user memory to be used as an extended key memory; eight
keys can be stored in each user zone (see Section 7.17).
Configuration Memory
The configuration memory contains all of the registers which control the user zone access requirements, the key usage
restrictions, and the counter usage restrictions. The device level configuration option registers are also located in configuration
memory.
The ATAES132 configuration memory includes a register programmed with unique read-only die identification data at the
factory. The configuration memory also contains several registers for customer information. The Configuration memory
registers can always be read using the BlockRead command (see Section 7.4). The lock command is used to permanently
lock the contents of the configuration memory after personalization (see Section 7.19).
See Table 2-1 for a summary of the configuration memory registers sorted by register name. See Appendix E for the
configuration memory map.
Atmel ATAES132 Preliminary Datasheet
2
C commands if a user zone is configured for open
2
C write commands (see
8760A−CRYPTO−5/11
9