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参数资料
| 型号： | DS1554W-120 |
| 厂商： | DALLAS SEMICONDUCTOR |
| 元件分类： | Timer or RTC |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, PDMA32 |
| 封装： | DIP-32 |
| 文件页数： | 19/21页 |
| 文件大小： | 284K |
| 代理商： | DS1554W-120 |
DS1554
7 of 21
SETTING THE CLOCK
The 8th bit, B7 of the Control Register is the write bit. Setting the write bit to a 1, like the read bit, halts
updates to the DS1554 (7FF8h-7FFFh) registers. After setting the write bit to a 1, RTC Registers can be
loaded with the desired RTC count (day, date, and time) in 24-hour BCD format. Setting the write bit to a
0 then transfers the values written to the internal RTC Registers and allows normal operation to resume.
CLOCK ACCURACY (DIP MODULE)
The DS1554 is guaranteed to keep time accuracy to within
±1 minute per month at 25°C. The RTC is
calibrated at the factory by Dallas Semiconductor using nonvolatile tuning elements. The DS1554 does
not require additional calibration and, in most applications, temperature deviations will have a negligible
effect on accuracy. For this reason, methods of field clock calibration are not available and not necessary.
Attempts to calibrate the RTC that may be used with similar device types (M48T5x family) will not have
any effect even though the DS1554 appears to accept calibration data.
CLOCK ACCURACY (POWERCAP MODULE)
The DS1554 and DS9034PCX are each individually tested for accuracy. Once mounted together, the
module is guaranteed to keep time accuracy to within
±1.53 minutes per month (35 ppm) at 25°C.
FREQUENCY TEST MODE
The DS1554 frequency test mode uses the open drain IRQ /FT output. With the oscillator running, the
IRQ
/FT output will toggle at 512 Hz when the FT bit is a 1, the Alarm Flag Enable bit (AE) is a 0, and
the Watchdog Steering bit (WDS) is a 1 or the Watchdog Register is reset (Register 7FF7h = 00h). The
IRQ
/FT output and the frequency test mode can be used as a measure of the actual frequency of the
32.768 kHz RTC oscillator. The IRQ /FT pin is an open drain output which requires a pullup resistor for
proper operation. The FT bit is cleared to a 0 on power-up.
USING THE CLOCK ALARM
The alarm settings and control for the DS1554 reside within Registers 7FF2h-7FF5h. Register 7FF6h
contains two alarm enable bits: Alarm Enable (AE) and Alarm in Backup Enable (ABE). The AE and
ABE bits must be set as described below for the IRQ /FT output to be activated for a matched alarm
condition.
The alarm can be programmed to activate on a specific day of the month or repeat every day, hour,
minute, or second. It can also be programmed to go off while the DS1554 is in the battery backed state of
operation to serve as a system wake-up. Alarm mask bits AM1-AM4 control the alarm mode. Table 3
shows the possible settings. Configurations not listed in the table default to the once per second mode to
notify the user of an incorrect alarm setting.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1554P-70 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1554 | REAL TIME CLOCK, DMA32 |
| DS1556-70 | REAL TIME CLOCK, PDMA32 |
| DS1556W-120 | REAL TIME CLOCK, DMA32 |
| DS1556 | REAL TIME CLOCK, DMA32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1554W-120+ | 功能描述:实时时钟 256kB NV RAM Timekeeper 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 |
| DS1554W-120IND | 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 |
| DS1554W-120IND+ | 功能描述:实时时钟 256kB NV RAM Timekeeper 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 |
| DS1554W-150 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:256K NV Y2KC Timekeeping RAM |
| DS1554WP | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Real-Time Clock |
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