3.

Compatibility

3.1

Microchip ATECC608A

The ATECC608B is designed to provide an enhanced security profile over that of the ATECC608A while maintaining

backwards compatibility. The following details the changes and enhancements to the device. No configuration bit

fields have changed. Configurations defined for the ATECC608A will be functionally identical with the ATECC608B

device.

Corrections, Enhancements

The following items have been corrected or enhanced in the ATECC608B device:

• Two temperature ranges are now available:

– Standard Industrial Temperature Range: -40℃ to +85℃

– Standard Industrial Temperature Range: -40℃ to +100℃

• Operating at a low I2C Frequency with multiple devices on the bus will no longer create a bus contention issue.

• Modifications to Command Timings for Verify, SecureBoot, Lock and Read commands.

• New Packaging Options: 3-Lead Contact Package and WLCSP for qualified customers. (Contact Microchip

Sales for the WLCSP Option.)

3.2

Microchip ATECC508A

The ATECC608B is designed to be fully compatible with the ATECC508A devices with the limited exception of the

functions listed below. If the ATECC608B is properly configured, software written for the ATECC508A will work with

the ATECC608B without any required changes, again with the exception of the functions listed below.

Note:  Most elements of the configuration zone in the ATECC608B are identical in both location and value with the

ATECC508A. However, the initial values that had been stored in the LastKeyUse field may need to be changed to

conform to the new definition of those bytes which can be found in this document. That field contained the initial

count for the Slot 15 limited use function which is supported in the ATECC608B via the monotonic counters.

CAUTION

The execution times of commands have changed between the ATECC608B and the ATECC508A. These

changes will not cause an issue if polling has been implemented. If fixed timing has been used, this must

be evaluated and updated as required.

New Features in ATECC608B vs. ATECC508A

• Secure boot function with IO encryption and authentication

• KDF command, supporting PRF, HKDF, AES

• AES command, including encrypt/decrypt

• GFM calculation function for GCM AEAD mode of AES

• Updated NIST SP800-90 A/B/C Random Number Generator

• Flexible SHA/HMAC command with context save/restore

• SHA command execution time significantly reduced

• Volatile Key Permitting to prevent device transfer

• Transport Key Locking to protect programmed devices during delivery

• Counter Limit Match function

• Ephemeral key generation in SRAM, also supported with ECDH and KDF

• Verify command output can be validated with a MAC

• Encrypted output for ECDH

ATECC608B

Compatibility

© 2020 Microchip Technology Inc.

Summary Datasheet

DS40002239A-page 12