參數(shù)資料
型號(hào): DS1554W-120
英文描述: 256K NV Y2KC Timekeeping RAM
中文描述: 256K內(nèi)存時(shí)鐘非易失Y2KC
文件頁數(shù): 7/21頁
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.
相關(guān)PDF資料
PDF描述
DS1554 256K NV Y2KC Timekeeping RAM
DS1554P-70 256K NV Y2KC Timekeeping RAM
DS1554P-100 256K NV Y2KC Timekeeping RAM
DS1554WP-150 256K NV Y2KC Timekeeping RAM
DS1554WP-120 256K NV Y2KC Timekeeping RAM
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1554W-120+ 功能描述:實(shí)時(shí)時(shí)鐘 256kB NV RAM Timekeeper 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
DS1554W-120IND 功能描述:實(shí)時(shí)時(shí)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(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
DS1554W-120IND+ 功能描述:實(shí)時(shí)時(shí)鐘 256kB NV RAM Timekeeper 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
DS1554W-150 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:256K NV Y2KC Timekeeping RAM
DS1554WP 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock