DS2705K Maxim Integrated, DS2705K Datasheet - Page 4

• Manufacturer Part Number: DS2705K
• Description: Power Management IC Development Tools
• Manufacturer: Maxim Integrated
• Series: DS2705r

DS2705EVKIT+
MAIN Interface
The DS2705 stores an 8 byte Challenge, a 20 byte Response, and a 2 byte Configuration Register in EEPROM.
The Secret is only used by software to create the proper Response for any given Challenge and is never
transmitted across the 1-Wire bus. The “Read” and “Write” buttons allow access to the Shadow RAM. The “Copy”
and “Recall” buttons issue the commands to transfer the data between the Shadow RAM and EEPROM.
The Secret
The user is able to enter the 8 bytes of the Secret into the text boxes. The top-right text box is the LSB of the
Secret, and the bottom-left text box is the MSB of the Secret. (All text boxes are displayed in this same format.)
The Secret is not stored in the DS2705; it is only used by the DS2705 EV kit software to calculate the appropriate
Response for a given Challenge. It is important that the Secret entered here is the same secret that is stored in the
DS2703/DS2704 that is being authenticated.
The Challenge
The Challenge is a random 8 byte block, stored in EEPROM of the DS2705, which is used by the Maxim SHA
devices to perform the SHA-1 encryption algorithm. Each time an authentication attempt is made, the DS2705
sends the 8 byte Challenge.
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