ATAES132-SH-EQ-T Atmel, ATAES132-SH-EQ-T Datasheet - Page 103

• Manufacturer Part Number: ATAES132-SH-EQ-T
• Description: EEPROM AES 32Kbit EE SPI
• Manufacturer: Atmel

Specifications of ATAES132-SH-EQ-T

• Rohs: yes
• Maximum Clock Frequency: 10 MHz
• Operating Supply Voltage: 6 V
• Maximum Operating Temperature: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-8
• Interface Type: SPI
• Factory Pack Quantity: 4000

Appendix H. Understanding the Non-Reversible Monotonic Counters
H.1.1. Monotonic Counter Registers
H.1.2. Reading the Monotonic Counters
Each monotonic counter can increment up to a value of 2,097,134 using the count command, after which, can be no longer
changed. Counters attached to keys are also incremented each time the key is used – when the counter reaches its limit the
key is disabled. The value in the counter can never be reset or lowered. The counters include a power interruption protection
feature to prevent corruption of the count value if power is removed during the increment operation.
On shipment from Atmel, the counter registers are initialized to their lowest value. The initial value of each counter may be
written to a different value at personalization, prior to locking the configuration.
Each monotonic counter register contains two count values to prevent the count value from being corrupted if power is
interrupted during a counter increment operation. Each count value is stored as a combination of two count fields:
Table H-1 shows the location of the count fields within the counter register in configuration memory.
Table H-31. Partial configuration memory map showing counter register field locations
The counter registers can always be read from the configuration memory using the BlockRead command. However, the count
command is the preferred method of reading the counters. When the counter is read using the count command, the
ATAES132 automatically selects the appropriate counter register fields and returns them to the host in the response packet.
See Section 7.5 for the counter command.
The counter command is the recommended method for reading a counter. The counter command returns a 4 byte
CountValue field which is formatted as shown in Table H-2. Optionally, the counter command can also return a MAC for
cryptographic authentication of the CountValue. The definition of the CountValue field is shown in Table H-3. See Section 7.5
for the counter command.
Table H-32. CountValue field
The CountValue contains a linear counter field (LinCount), a binary counter field (BinCount), and the CountFlag field. The
CountFlag field indicates if the counter value was read from the Counter A or Counter B EEPROM location. CountFlag also
indicates if the eight bit LinCount field is the Most Significant Byte (MSB) or Least Significant Byte (LSB) of the 16 bit LinCount
field in EEPROM. If the LSB of LinCount has been returned, then the LinCount field value is one to eight; if the MSB of
LinCount has been returned, then the LinCount field value is 9 to 16.
Address
F100
1.
3.
LinCount
h
Counter A is stored in LinCountA and BinCountA
Counter B is stored in LinCountB and BinCountB
-F107
Byte 0
h
0
h
LinCountA
CountFlag
Byte 1
1
h
2
h
Byte 2
LinCountB
BinCount
3
h
Counter 00
Byte 3
Atmel ATAES132 Preliminary Datasheet
4
h
BinCountB
5
h
8760A−CRYPTO−5/11
6
h
BinCountA
7
h
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