ATSHA204 datasheet(45/65 Pages) ATMEL

45 / 65 page

Atmel ATSHA204 [DATASHEET]

8740D

−CRYPTO−3/12

8.7

Lock Command

Write either LockConfig or LockValue to 0xFF, thereby changing the permissions in the designated zone.

This command fails if the designated zone is already locked.

Prior to locking the device, the ATSHA204 uses the CRC-16 algorithm to generate a summary digest of the designated

zone(s). The calculation is made identically to the CRC computed over the input and output blocks.

• For the configuration zone, the CRC is calculated over all 88 bytes.

• For the data and OTP zones, their contents are concatenated in that order to create the input to the CRC algorithm.

If the input summary does not match that computed on the device, an error is returned and the personalization process should

be repeated.

Table 8-20. Input Parameters

Name

Size

Notes

Opode

LOCK

0x17

Param1

Zone

Bit 0: Zero for config zone, 1 for data and OTP zones.

Bits 1-6: Must be zero.

Bit 7: If one, the check of the zone CRC is ignored and the zone is locked, regardless

of the state of the memory. Atmel does not recommend using this mode.

Param2

Summary

Summary of the designated zones, or should be 0x0000 if Zone[7] is set.

Data

Table 8-21. Output Parameter

Name

Size

Notes

Success

Upon successful execution, the Atmel ATSHA204 returns a value of zero.

ATSHA204 Datasheet(PDF) 45 Page - ATMEL Corporation