DS2778 Maxim Integrated Products, DS2778 Datasheet - Page 38

• Manufacturer Part Number: DS2778
• Description: 2-Cell Stand-Alone Li+ Fuel-Gauge IC
• Manufacturer: Maxim Integrated Products

2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
register, address 1Fh, bit 6) to a 1. If the LOCK bit is 0
or if setting the LOCK bit to 1 does not immediately
precede the Lock command, the Lock command has
Table 12. All Function Commands
Table 13. Guide to Function Command Requirements
38
Write Challenge
Compute MAC without ROM ID (and
Return MAC for the DS2776 only)
Compute MAC with ROM ID (and Return
MAC for the DS2776 only)
Clear Secret
Compute Next Secret without the ROM ID
Compute Next Secret with ROM ID
Read ROM ID (DS2778 only)
Read MAC (DS2778 only)
Lock Secret
Read Data
Write Data
Copy Data
Recall Data
Lock
Reset
Write Challenge
Compute MAC
Compute Next Secret
Clear/Lock Secret, Set/Clear
Read Data
Write Data
Copy Data
Recall Data
Lock
Reset
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COMMAND
COMMAND
ISSUE MEMORY ADDRESS
6Ch, XXh Writes data to memory starting at address XXh.
B8h, XXh Recalls EEPROM block containing address XXh to RAM.
6Ah, XXh Permanently locks the block of EEPROM containing address XXh.
69h, XXh Reads data from memory starting at address XXh.
48h, XXh Copies shadow RAM data to EEPROM block containing address XXh.
(BITS)
HEX
BBh
0Ch
5Ah
36h
35h
30h
33h
3Ah
60h
39h
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8
8
8
8
8
Writes 64-bit challenge for SHA-1 processing. Required immediately prior
to all Compute MAC and Compute Next Secret commands.
Computes hash of the message block with logical 1s in place of ROM ID.
(Returns the 160-bit MAC for the DS2776 only.)
Computes hash of the message block using the ROM ID. (Returns the
160-bit MAC for the DS2776 only.)
Clears the 64-bit secret to 0000 0000 0000 0000h.
Generates new global secret.
Generates new unique secret.
Returns the ROM ID (DS2778 only).
Returns the 160-bit MAC (DS2778 only).
Sets lock bit to prevent changes to the secret.
Resets DS2775/DS2776 (software POR).
ISSUE 00h BEFORE READ
no effect. The Lock command is permanent; a locked
block can never be written again.
Yes
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DESCRIPTION
READ/WRITE TIME SLOTS
Read: Up to 2048
Write: Up to 2048
Read: Up to 160
Write: 64
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