AT88SC6416CRF-MR1 View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT88SC6416CRF-MR1

CryptoRF® Specification

Atmel Corporation 

AT88SC0808/1616/3216/6416CRF, AT88RF04C

Table 103 shows the consequences of a tearing attack occurring at each step during an anti-tearing write. The

EEPROM contents at the address being written will either remain unchanged, or will be written with the new data. The

EEPROM is not corrupted by power interruption during an anti-tearing write operation.

Table 103. Consequences of a Tearing Event during an Anti-Tearing Write

Step

Description

Result if Power is interrupted Mid-Step

1 Write Buffer Memory

Original EEPROM Contents are Unchanged

2 Write Anti-Tearing Flag

Original EEPROM Contents are Unchanged

3 Write Final Memory

Anti-Tearing Write Completes on POR

4 Clear Anti-Tearing Flag

Anti-Tearing Write Completes on POR

L.3.

Performance Impact of Anti-Tearing

Anti-tearing impacts the CryptoRF write transaction time in two ways. First, the maximum length of a write command is

limited to 8 bytes when anti-tearing is active. Second, the response time of a write command is increased by

approximately four times due to additional EEPROM memory writes which occur when anti-tearing is active.

If anti-tearing is used to write 8 bytes of data, the net result is an increase in the transaction time of only 5 milliseconds.

When large amounts of data are written, the increase in transaction time is significant. Writing the entire 128 byte User

Zone on AT88RF04C takes 155 milliseconds with anti-tearing, but only 47 milliseconds without anti-tearing. Writing the

entire 256 byte User Zone on AT88SC3216CRF takes 292 milliseconds with anti-tearing, but only 54 milliseconds

without anti-tearing.

Table 104. CryptoRF Family Write Characteristics with Anti-Tearing

CryptoRF

Part Number

Write Characteristics

Standard Write Anti-Tearing Write

AT88RF04C

1 to 16 bytes

1 to 8 bytes

AT88SC0808CRF

1 to 16 bytes

1 to 8 bytes

AT88SC1616CRF

1 to 16 bytes

1 to 8 bytes

AT88SC3216CRF

1 to 32 bytes

1 to 8 bytes

AT88SC6416CRF

1 to 32 bytes

1 to 8 bytes

5276C–RFID–3/09

127

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