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参数资料
| 型号： | BQ3285S |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | XO, clock |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| 封装： | 0.300 INCH, PLASTIC, SOIC-24 |
| 文件页数： | 23/26页 |
| 文件大小： | 676K |
| 代理商： | BQ3285S |
Square-Wave Output
The bq3285 divides the 32.768kHz oscillator frequency
to produce the 1Hz update frequency for the clock and
calendar. Thirteen taps from the frequency divider are
fed to a 16:1 multiplexer circuit. The output of this mux
is fed to the SQW output and periodic interrupt genera-
tion circuitry. The four least-significant bits of register
A, RS0–RS3, select among the 13 taps (see Table 3). The
square-wave output is enabled by writinga1tothe
square-wave enable bit (SQWE) in register B.
Interrupts
The bq3285 allows three individually selected interrupt
events to generate an interrupt request. These three in-
terrupt events are:
n
The periodic interrupt, programmable to occur once
every 122
s to 500ms
n
The alarm interrupt, programmable to occur once per
second to once per day
n
The update-ended interrupt, which occurs at the end
of each update cycle
Each of the three interrupt events is enabled by an indi-
vidual interrupt-enable bit in register B. When an event
occurs, its event flag bit in register C is set. If the corre-
sponding event enable bit is also set, then an interrupt
request is generated.
The interrupt request flag bit
(INTF) of register C is set with every interrupt request.
Reading register C clears all flag bits, including INTF,
and makes INT high-impedance.
Two methods can be used to process bq3285 interrupt
events:
n
Enable interrupt events and use the interrupt request
output to invoke an interrupt service routine.
n
Do not enable the interrupts and use a polling routine
to periodically check the status of the flag bits.
The individual interrupt sources are described in detail
in the following sections.
6
Register A Bits
Square Wave
Periodic Interrupt
RS3
RS2
RS1
RS0
Frequency
Units
Period
Units
0000
None
0001
256
Hz
3.90625
ms
0010
128
Hz
7.8125
ms
0011
8.192
kHz
122.070
s
0100
4.096
kHz
244.141
s
0101
2.048
kHz
488.281
s
0110
1.024
kHz
976.5625
s
0111
512
Hz
1.95315
ms
1000
256
Hz
3.90625
ms
1001
128
Hz
7.8125
ms
1010
64
Hz
15.625
ms
1011
32
Hz
31.25
ms
1100
16
Hz
62.5
ms
1101
8
Hz
125
ms
1110
4
Hz
250
ms
1111
2
Hz
500
ms
Table 3. Square-Wave Frequency/Periodic Interrupt Rate
bq3285
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相关代理商/技术参数 |
参数描述 |
|---|---|
| BQ3285S- | 制造商:TI 制造商全称:Texas Instruments 功能描述:Real-Time Clock RTC |
| BQ3285S-SB2 | 功能描述:实时时钟 RTC IC with 114x8 NVSRAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| BQ3285S-SB2G4 | 功能描述:实时时钟 RTC IC with 114x8 NVSRAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| BQ3285S-SB2TR | 功能描述:实时时钟 RTC IC with 114x8 NVSRAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| BQ3285S-SB2TRG4 | 功能描述:实时时钟 RTC IC with 114x8 NVSRAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
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