Rainbow-electronics DS1339 Bedienungsanleitung PDF herunterladen (Seite 7)

DS1339

7 of 18

Figure 3. ALARM MASK BITS

ALARM 1 REGISTER MASK BITS

(BIT 7)

DY/DT

A1M4 A1M3 A1M2 A1M1

ALARM RATE

X 1 1 1 1 Alarm once per second

X 1 1 1 0 Alarm when seconds match

X 1 1 0 0 Alarm when minutes and seconds match

X 1 0 0 0 Alarm when hours, minutes, and seconds match

0 0 0 0 0 Alarm when date, hours, minutes, and seconds match

1 0 0 0 0 Alarm when day, hours, minutes, and seconds match

ALARM 2 REGISTER MASK BITS

(BIT 7)

DY/DT

A2M4 A2M3 A2M2

ALARM RATE

X 1 1 1 Alarm once per minute (00 second of every minute)

X 1 1 0 Alarm when minutes match

X 1 0 0 Alarm when hours and minutes match

0 0 0 0 Alarm when date, hours, and minutes match

1 0 0 0 Alarm when day, hours, and minutes match

SPECIAL PURPOSE REGISTERS

The DS1339 has two additional registers (control and status) that control the RTC, alarms, and square-

wave output.

CONTROL REGISTER (0Eh)

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

EOSC

0 BBSQI RS2 RS1 INTCN A2IE A1IE

EOSC (Enable Oscillator) – This bit when set to logic 0 starts the oscillator. When this bit is set to a

logic 1, the oscillator is stopped. This bit is enabled (logic 0) when power is first applied.

BBSQI (Battery-Backed Square-Wave and Interrupt Enable) – This bit when set to a logic 1 enables

the square-wave or interrupt output when V

is absent and the DS1339 is being powered by the V

BACKUP

pin. When BBSQI is a logic 0, the SQW/ INT pin goes high impedance when V

falls below the power-

fail trip point. This bit is disabled (logic 0) when power is first applied.

RS2 and RS1 (Rate Select) – These bits control the frequency of the square-wave output when the

square wave has been enabled. Figure 4 shows the square-wave frequencies that can be selected with the

RS bits. These bits are both set to logic 1 (32kHz) when power is first applied.

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