ATSGA204A View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'ATSGA204A' PDF : 93 Pages View PDF
ATSHA204A
Compatibility
9. Compatibility
The ATSHA204A is designed to be fully compatible with the ATSHA204 for all Host, Client and
personalization operations. Note the following important refinements that have been made to the
ATSHA204A:
• Active power consumption is lower.
• Two-wire connection mode is supported without the requirement for an external diode.
• The new SHA command permits general computation of a SHA digest without the need for crypto
software in the Host.
• Write operations during personalization always require a MAC to be passed to the device to
prevent man-in-the-middle attacks. (Some versions of the ATSHA204 ignored the MAC on Write
when the Data zone was unlocked.)
• The UpdateExtra command can now be used to quickly decrement the limited-use counters
when a multi-step count is required.
• The Copy mode of the CheckMac command can now be run with a fixed nonce which simplifies the
implementation of protected secure boot validation and other related tasks.
• The new Consumption mode on the OTP zone provides additional capability for usage tracking.
• Write operations to the OTP or Data zone require 32 bytes when the Configuration zone is locked
and the OTP and Data zones are unlocked. The ATSHA204 allowed 4 byte Write commands for
this lock state.
© 2018 Microchip Technology Inc.
DS40002025A-page 66
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