DS1216

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SMARTWATCH COMPARISON REGISTER DEFINITION Figure 1

Note: The pattern recognition in Hex is C5, 3A, 5C, C5, 3A, A3, 5C. The odds of this pattern

pattern is sent to the SmartWatch LSB to MSB.

After power-up, the controller could be in the 64-bit clock register read/write sequence (from an

incomplete access prior to power-down). Therefore, it is recommended that a 64-bit read be performed

upon power-up to prevent accidental writes to the clock, and to prevent reading clock data when access to

the RAM would otherwise be expected.

NONVOLATILE CONTROLLER OPERATION

The DS1216 SmartWatch performs circuit functions required to make a CMOS RAM nonvolatile. First, a

This switch has a voltage drop of less than 0.2V. The second function that the SmartWatch provides is

goes out of tolerance, a comparator outputs a power-fail signal to the chip-enable logic. The third function

battery. During nominal power-supply conditions, the memory chip-enable signal will track the chip-

enable signal sent to the socket with a maximum propagation delay of 7ns for the 5V and 12ns for the

3.3V version.

FRESHNESS SEAL

Each DS1216 is shipped from Dallas Semiconductor with its lithium energy source disconnected,

is enabled for battery-backup operation.

1

1

0001

0

1

0

0

1110

1

0

1

0

1000

1

1

0

1

0111

0

0

1

1

0001

0

1

0

0

1110

1

0

1

0

1000

1

1

0

1

0111

0

0

BYTE 0

BYTE 1

BYTE 2

BYTE 3

BYTE 4

BYTE 5

BYTE 6

BYTE 7

C5

3A

A3

5C

C5

3A

A3

5C

HEX

VALUE

7

0