IDT1339 Integrated Device Technology, IDT1339 Datasheet - Page 8

• Manufacturer Part Number: IDT1339
• Description: Real-time Clock With Serial I 2c Interface
• Manufacturer: Integrated Device Technology

Table 4. Alarm Mask Bits
Special-Purpose Registers
The IDT1339 has two additional registers (control and status) that control the RTC, alarms, and square-wave output.
Control Register (0Eh)
IDT™ REAL-TIME CLOCK WITH SERIAL I
DY/DT
DY/DT
IDT1339
REAL-TIME CLOCK WITH SERIAL I
EOSC
Bit 7
X
X
X
X
X
X
X
0
1
0
1
Bit 7: Enable Oscillator (EOSC). 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.
Bit 5: Battery-Backed Square-Wave and Interrupt Enable (BBSQI). This bit when set to a logic 1 enables the
square wave or interrupt output when
BBSQI is a logic 0, the SQW/INT pin goes high impedance when
disabled (logic 0) when power is first applied.
Bits 4 and 3: Rate Select (RS2 and RS1). These bits control the frequency of the square-wave output when the
square wave has been enabled. Table 5 shows the square-wave frequencies that can be selected with the RS bits.
These bits are both set to logic 1 (32 kHz) when power is first applied.
A1M4
A2M4
Alarm 1 Register Mask Bits (Bit 7)
Alarm 2 Register Mask Bits (Bit 7)
1
1
1
1
0
0
1
1
1
0
0
Bit 6
0
A1M3
A2M3
1
1
1
0
0
0
1
1
0
0
0
BBSQI
Bit 5
A1M2
2
1
1
0
0
0
0
C INTERFACE
2
A2M2
C INTERFACE
Bit 4
RS2
1
0
0
0
0
A1M1
1
0
0
0
0
0
V
CC
Bit 3
RS1
Alarm once per second.
Alarm when seconds match.
Alarm when minutes and seconds match.
Alarm when hours, minutes, and seconds match.
Alarm when date, hours, minutes, and seconds match.
Alarm when day, hours, minutes, and seconds match.
Alarm once per minute (00 sec. of every min.).
Alarm when minutes match.
Alarm when hours and minutes match.
Alarm when date, hours, and minutes match.
Alarm when day, hours, and minutes match.
is absent and the IDT1339 is being powered by the V
INTCN
Bit 2
8
Bit 1
A2IE
V
CC
Alarm Rate
Alarm Rate
falls below the power-fail trip point. This bit is
Bit 0
A1IE
IDT1339
BACKUP
REV H 112008
pin. When
RTC