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参数资料
| 型号： | DS1742W-120 |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Timer or RTC |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, PDIP24 |
| 封装： | 0.740 INCH, ENCAPSULATED, DIP-24 |
| 文件页数： | 11/16页 |
| 文件大小： | 272K |
| 代理商： | DS1742W-120 |
DS1742
4 of 16
SETTING THE CLOCK
As shown in Table 2, bit 7 of the century register is the write bit. Setting the write bit to a 1, 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 0 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 increase the shelf life, the oscillator can be
turned off to minimize current drain from the battery. The OSC bit is the MSB (bit 7) of the
seconds registers, see Table 2. Setting it to a 1 stops the oscillator.
FREQUENCY TEST BIT
As shown in Table 2, 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,
low,
OE
WE
high, and address for
seconds register remain valid and stable).
CLOCK ACCURACY
The DS1742 is guaranteed to keep time accuracy to within ±1 minute per month at 25°C. Dallas
Semiconductor calibrates the RTC at the factory using nonvolatile tuning elements. The
DS1742 does not require additional calibration. For this reason, methods of field clock
calibration are not available and not necessary. Clock accuracy is also affected by the electrical
environment and caution should be taken to place the RTC in the lowest level EMI section of
the PCB layout. For additional information refer to Application Note 58.
Table 2. REGISTER MAP
DATA
ADDRES
S
B7
B6
B5
B4
B3
B2
B1
B0
FUNCTION
RANGE
7FF
10 Year
Year
00–99
7FE
X
10
Month
01–12
7FD
X
10 Date
Date
01–31
7FC
BF
FT
X
Day
01–07
7FB
X
10 Hour
Hour
00–23
7FA
X
10 Minutes
Minutes
00–59
7F9
OSC
10 Seconds
Seconds
00–59
7F8
W
R
10 Century
Century
Control
00–39
OSC = STOP BIT
R = READ BIT
FT = FREQUENCY TEST
W = WRITE BIT
X = SEE NOTE BELOW
BF = BATTERY FLAG
Note: All indicated “X” bits are not used but must be set to “0” during write cycle to ensure proper clock operation.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1742-70 | 0 TIMER(S), REAL TIME CLOCK, PDIP24 |
| DS1742W-150 | 0 TIMER(S), REAL TIME CLOCK, DMA24 |
| DS1743P-70 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1743-70 | 0 TIMER(S), REAL TIME CLOCK, DMA28 |
| DS1743W-120 | 0 TIMER(S), REAL TIME CLOCK, DMA28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1742W-120+ | 功能描述:实时时钟 Timekeeping NV RAM 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 |
| DS1742W-150 | 功能描述:实时时钟 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 |
| DS1742W-150+ | 功能描述:实时时钟 Timekeeping NV RAM 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 |
| DS1743 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Y2K-Compliant, Nonvolatile Timekeeping |
| DS1743-100 | 功能描述:实时时钟 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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