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Rainbow Electronics DS2778 User Manual

Page 38

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DS2775/DS2776/DS2777/DS2778

2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication

38

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1-Wire
RESET

SKIP-ROM

COMMAND

UP TO 160 READ TIME SLOTS

(READ 20-BYTE MAC)

PRESENCE

PULSE

COMPUTE

MAC COMMAND

8 WRITE-ZERO

TIME SLOTS

WAIT FOR MAC
COMPUTATION

t

SHA

Figure 25. Compute MAC Command

1-Wire
RESET

SKIP-ROM

COMMAND

PRESENCE

PULSE

COMPUTE

NEXT SECRET COMMAND

WAIT FOR MAC
COMPUTATION

WAIT FOR EEPROM

PROGRAMMING

t

SHA

t

EEC

Figure 26. Compute Next Secret Command

1-Wire
RESET

SKIP-ROM

COMMAND

COPY DATA

COMMAND

8 WRITE

TIME SLOTS

PRESENCE

PULSE

WAIT FOR EEPROM

PROGRAMMING

t

EEC

Figure 27. Copy Data Command