DS2778K Maxim Integrated, DS2778K Datasheet - Page 10

• Manufacturer Part Number: DS2778K
• Description: Power Management IC Development Tools
• Manufacturer: Maxim Integrated
• Series: DS2775, DS2776, DS2777, DS2778r

DS2775–DS2778 Evaluation Kits
Figure 18. SHA-1 Tab
Figure 19. The Secret
Figure 20. The ROM ID
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The DS2776/DS2778 use an 8-byte Secret, the 8-byte
ROM ID code of the device, and an 8-byte Challenge
to generate a 20-byte Message Digest (also called the
MAC) using the SHA-1 encryption algorithm. See
Figure 18. The DS2775/DS2777 do not support the
SHA-1 functions.
The user can clear the 8 bytes of the secret by left-
clicking on the Clear Secret button. 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 dis-
played in this same format.) See Figure 19.
The user can also permanently lock the secret by left-
clicking on the Lock Secret button. Once the secret is
locked, it cannot be changed and cannot be read from
the DS2776/DS2778. The software prompts the user to
make sure the secret is ready to be permanently locked.