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DS1339U-33+ 参数 Datasheet PDF下载

DS1339U-33+图片预览
型号: DS1339U-33+
PDF下载: 下载PDF文件 查看货源
内容描述: I²C串行实时时钟 [I2C Serial Real-Time Clock]
分类和应用: 外围集成电路光电二极管时钟
文件页数/大小: 18 页 / 280 K
品牌: DALLAS [ DALLAS SEMICONDUCTOR ]
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DS1339 I2C Serial Real-Time Clock  
Table 2. Alarm Mask Bits  
ALARM 1 REGISTER MASK BITS  
(Bit 7)  
ALARM RATE  
DY/DT  
A1M4  
A1M3  
A1M2  
A1M1  
X
X
X
X
1
1
1
1
1
1
1
0
1
1
0
0
1
0
0
0
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  
0
1
0
0
0
0
0
0
0
0
Alarm when day, hours, minutes, and seconds match  
ALARM 2 REGISTER MASK BITS  
(Bit 7)  
ALARM RATE  
DY/DT  
A2M4  
A2M3  
A2M2  
X
X
X
0
1
1
1
0
0
1
1
0
0
0
1
0
0
0
0
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  
1
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  
0
BBSQI  
RS2  
RS1  
INTCN  
A2IE  
A1IE  
EOSC  
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 VCC is absent and the DS1339 is being powered by the VBACKUP pin. When  
BBSQI is a logic 0, the SQW/INT pin goes high impedance when VCC falls below the power-fail trip point. This bit is  
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. The table below 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.  
Square-Wave Output Frequency  
SQUARE-WAVE  
RS2  
RS1  
OUTPUT  
FREQUENCY  
1Hz  
0
0
1
1
0
1
0
1
4.096kHz  
8.192kHz  
32.768kHz  
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