DS2703 SHA-1 Battery Pack Authentication IC

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Table 7. All Function Commands

COMMAND

HEX

FUNCTION

Write Challenge

0C

Writes 64-bit challenge for SHA-1 processing. Required prior to all Compute

MAC and Compute Next Secret commands.

Compute MAC

without ROM_ID and

return MAC

36

Computes hash of W0-W15 with logical 1’s in place of the ROM_ID.

Compute MAC

with ROM_ID and

return MAC

35

Computes hash of W0-W15 with the ROM_ID.

Load Secret

5A

Writes the 64-bit Secret to supplied data. Requires programming voltage on

DQ.

Compute Next Secret

without ROM ID

30

Generates new global secret. Requires programming pulse.

Compute Next Secret

with ROM ID

33

Generates new unique secret. Requires programming pulse.

Lock Secret

6A

Sets lock bit to prevent changes to the Secret. Requires programming pulse.

Set Overdrive

8B

Sets 1-Wire interface timings to OVERDRIVE. Requires programming pulse.

Clear Overdrive

8D

Sets 1-Wire interface timings to STANDARD. Requires programming pulse.

Reset

BB

Resets DS2703 (Software POR).

Table 8. Guide to Function Command Requirements

COMMAND

STRONG PULLUP

ON DQ

ISSUE 00h

BEFORE READ

READ/WRITE

TIME SLOTS

PROGRAMMING

PULSE

Write Challenge

Write: 64

Compute MAC

X

X

Read: up to 160

Compute Next Secret

X

X

Lock Secret,

Set/Clear Overdrive

X

Load Secret

Write: 64

X

Reset