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參數(shù)資料
| 型號(hào)： | BQ3285ESSNTR |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | XO, clock |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| 封裝： | SSOP-24 |
| 文件頁數(shù)： | 34/37頁 |
| 文件大小： | 1438K |
| 代理商： | BQ3285ESSNTR |
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Square-Wave Output
The bq3285E/L divides the 32.768kHz oscillator fre-
quency
to produce the 1Hz update frequency for the
clock and calendar. Thirteen taps from the frequency di-
vider are fed to a 16:1 multiplexer circuit. The output of
this mux is fed to the SQW output and periodic inter-
rupt generation 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 writing
a 1 to the square-wave enable bit (SQWE) in register B.
A 32.768kHz output may be selected by setting
OSC2–OSC0 in register A to 011 while SQWE=1and
32KE = 1.
Interrupts
The bq3285E/L allows three individually selected inter-
rupt events to generate an interrupt request.
These
three interrupt 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, is active in battery-backup
mode, providing a “wake-up” feature.
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 bq3285E/L 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
OSC2
OSC1
OSC0
RS3
RS2
RS1
RS0
Frequency
Units
Period
Units
0100000
None
0100001
256
Hz
3.90625
ms
0100010
128
Hz
7.8125
ms
0100011
8.192
kHz
122.070
s
0100100
4.096
kHz
244.141
s
0100101
2.048
kHz
488.281
s
0100110
1.024
kHz
976.5625
s
0100111
512
Hz
1.95315
ms
0101000
256
Hz
3.90625
ms
0101001
128
Hz
7.8125
ms
0101010
64
Hz
15.625
ms
0101011
32
Hz
31.25
ms
0101100
16
Hz
62.5
ms
0101101
8
Hz
125
ms
0101110
4
Hz
250
ms
0101111
2
Hz
500
ms
0
1
XXXX
32.768
kHz
same as above defined
by RS3–RS0
Table 3. Square-Wave Frequency/Periodic Interrupt Rate
bq3285E/L
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| BQ3285ESSN | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| BQ3285LCSS | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| BQ3285ECSS | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| BQ4285Q | 1 TIMER(S), REAL TIME CLOCK, PQCC28 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| BQ3285ESSTR | 功能描述:實(shí)時(shí)時(shí)鐘 w/242x8 NVSRAM Alarm Wake-up RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| BQ3285ESS-TR1 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| BQ3285ESSTRG4 | 功能描述:實(shí)時(shí)時(shí)鐘 w/242x8 NVSRAM Alarm Wake-up RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| BQ3285ESTR | 功能描述:實(shí)時(shí)時(shí)鐘 w/242x8 NVSRAM Alarm Wake-up RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| BQ3285ESTRG4 | 功能描述:實(shí)時(shí)時(shí)鐘 w/242x8 NVSRAM Alarm Wake-up RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
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