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參數(shù)資料
| 型號： | DS1742 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Y2KC Nonvolatile Timekeeping RAM(Y2KC非易失性計時RAM) |
| 文件頁數(shù)： | 2/13頁 |
| 文件大?。?/td> | 95K |
| 代理商： | DS1742 |
DS1742
061998 2/13
CLOCK OPERATIONS–READING THE
CLOCK
While the double buffered register structure reduces the
chance of reading incorrect data, internal updates to the
DS1742 clock registers should be halted before clock
data is read to prevent reading of data in transition.
However, halting the internal clock register updating
process does not affect clock accuracy. Updating is
halted when a one is written into the read bit, bit 6 of the
century register, see Table 2. As long as a one remains
in that position, updating is halted. After a halt is issued,
the registers reflect the count, that is day, date, and time
that was current at the moment the halt command was
issued. However, the internal clock registers of the
double buffered system continue to update so that the
clock accuracy is not affected by the access of data. All
of the DS1742 registers are updated simultaneously af-
ter the internal clock register updating process has been
re–enabled. Updating is within a second after the read
bit is written to zero.
DS1742 BLOCK DIAGRAM
Figure 1
OSCILLATOR AND
CLOCK COUNTDOWN
CHAIN
POWER MONITOR,
SWITCHING, AND
WRITE PROTECTION
V
CC
CLOCK
REGISTERS
2K X 8
NV SRAM
CE
WE
A0–A10
DQ0–DQ7
32.768 KHz
+
OE
V
BAT
DS1742 TRUTH TABLE
Table 1
V
CC
CE
OE
WE
MODE
DQ
POWER
I T l
In Tolerance
V
IH
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
<Tolerance >V
BAT
X
X
X
DESELECT
HIGH–Z
CMOS STANDBY
<V
BAT
X
X
X
DESELECT
HIGH–Z
DATA RETENTION
MODE
SETTING THE CLOCK
As shown in Table 2, bit 7 of the century register is the
write bit. Setting the write bit to a one, like the read bit,
halts updates to the DS1742 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.
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相關(guān)代理商/技術(shù)參數(shù) |
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|---|---|
| DS1742-100 | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1742-100+ | 功能描述:實時時鐘 Timekeeping NV RAM 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1742-100IND | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1742-100IND+ | 功能描述:實時時鐘 Timekeeping NV RAM 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1742-70 | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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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