DS14285/DS14287

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REGISTER B

MSB

LSB

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

SET

PIE

AIE

UIE

SQWE

DM

24/12

DSE

SET - When the SET bit is a 0, the update transfer functions normally by advancing the counts once per

second. When the SET bit is written to a 1, any update transfer is inhibited and the program can initialize

the time and calendar bytes without an update occurring in the midst of initializing. Read cycles can be

of the DS14285/DS14287.

PIE - The periodic interrupt enable PIE bit is a read/write bit which allows the Periodic Interrupt Flag

still set at the periodic rate. PIE is not modified by any internal DS14285/DS14287 functions, but is

AIE - The Alarm Interrupt Enable (AIE) bit is a read/write bit which, when set to a 1, permits the Alarm

equal the 3 alarm bytes including a “don’t care” alarm code of binary 11XXXXXX. When the AIE bit is

functions of the DS14285/DS14287 do not affect the AIE bit.

UIE - The Update Ended Interrupt Enable (UIE) bit is a read/write that enables the Update End Flag (UF)

SQWE - When the Square Wave Enable (SQWE) bit is set to a 1, a square wave signal at the frequency

set by the rate-selection bits RS3 through RS0 is driven out on a SQW pin. When the SQWE bit is set to

DM - The Data Mode (DM) bit indicates whether time and calendar information is in binary or BCD

format. The DM bit is set by the program to the appropriate format and can be read as required. This bit is

specifies Binary Coded Decimal (BCD) data.

24/12 - The 24/12 control bit establishes the format of the hours byte. A 1 indicates the 24-hour mode and

DSE - The Daylight Savings Enable (DSE) bit is a read/write bit which enables two special updates when

DSE is set to 1. On the first Sunday in April the time increments from 1:59:59 AM to 3:00:00 AM. On

the last Sunday in October when the time first reaches 1:59:59 AM it changes to 1:00:00 AM. These

special updates do not occur when the DSE bit is a 0. This bit is not affected by internal functions or

RESET

.