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參數(shù)資料
| 型號(hào)： | DS1644L-120 |
| 英文描述： | Nonvolatile Timekeeping RAM |
| 中文描述： | 非易失性內(nèi)存時(shí)鐘 |
| 文件頁數(shù)： | 3/11頁 |
| 文件大?。?/td> | 108K |
| 代理商： | DS1644L-120 |
DS1644LPM
041697 3/11
DS1644L TRUTH TABLE
Table 1
V
CC
CE
OE
WE
MODE
DQ
POWER
5 VOLTS
±
10%
V
IH
X
X
DESELECT
HIGH–Z
STANDBY
X
X
X
DESELECT
HIGH–Z
STANDBY
V
IL
X
V
IL
WRITE
DATA IN
ACTIVE
V
IL
V
IL
V
IH
READ
DATA OUT
ACTIVE
V
IL
V
IH
V
IH
READ
HIGH–Z
ACTIVE
<4.5 VOLTS
>V
BAT
X
X
X
DESELECT
HIGH–Z
CMOS STANDBY
<V
BAT
X
X
X
DESELECT
HIGH–Z
DATA RETENTION
MODE
SETTING THE CLOCK
The eighth bit of the control register is the write bit. Set-
ting the write bit to a one, like the read bit, halts updates
to the DS1644L registers. The user can then load them
with the correct day, date and time data in 24 hour BCD
format. Resetting the write bit to a zero then transfers
those values to the actual clock counters and allows
normal operation to resume.
STOPPING AND STARTING THE CLOCK
OSCILLATOR
The clock oscillator may be stopped at any time. To in-
crease the shelf life, the oscillator can be turned off to
minimize current drain from the battery. The OSC bit is
the MSB for the seconds registers. Setting it to a one
stops the oscillator.
FREQUENCY TEST BIT
Bit 6 of the day byte is the frequency test bit. When the
frequency test bit is set to logic “1” and the oscillator is
running, the LSB of the seconds register will toggle at
512 Hz. When the seconds register is being read, the
DQ0 line will toggle at the 512 Hz frequency as long as
conditions for access remain valid (i.e., CE low, OE low,
and address for seconds register remain valid and
stable).
CLOCK ACCURACY
The DS1644L is guaranteed to keep time accuracy to
within
±
1 minute per month at 25
°
C. The clock is cali-
brated at the factory by Dallas Semiconductor using
special calibration nonvolatile tuning elements. The
DS1644L does not require additional calibration, and
temperature deviations will have a negligible effect in
most applications. For this reason, methods of field
clock calibration are not available and not necessary.
Attempts to calibrate the clock that may be used with
similar device types (MK48T08 family) will not have any
effect even though the DS1644L appears to accept cal-
ibration data.
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| DS1644L-150 | Nonvolatile Timekeeping RAM |
| DS1644LPM | Nonvolatile Timekeeping RAM |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1644L-15 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock |
| DS1644L-150 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644LPM | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P+120 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
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