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参数资料
| 型号： | DS1556-70 |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Timer or RTC |
| 英文描述： | REAL TIME CLOCK, PDMA32 |
| 封装： | EDIP MODULE-32 |
| 文件页数： | 21/23页 |
| 文件大小： | 443K |
| 代理商： | DS1556-70 |
DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM
7 of 21
READING THE CLOCK
When reading the RTC data, it is recommended to halt updates to the external set of double-buffered RTC
Registers. This puts the external registers into a static state allowing data to be read without register
values changing during the read process. Normal updates to the internal registers continue while in this
state. External updates are halted when a 1 is written into the read bit, B6 of the Control Register
(1FFF8h). As long as a 1 remains in the Control Register read bit, updating is halted. After a halt is
issued, the registers reflect the RTC count (day, date, and time) that was current at the moment the halt
command was issued. Normal updates to the external set of registers will resume within 1 second after the
read bit is set to a 0 for a minimum of 500
ms. The read bit must be a zero for a minimum of 500ms to
ensure the external registers will be updated.
SETTING THE CLOCK
The MSB 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 DS1556 (1FFF8h to 1FFFFh) 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 DS1556 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, and does not require
additional calibration. For this reason, methods of field clock calibration are not available and not
necessary. The electrical environment also affects clock accuracy, and caution should be taken to place
the RTC in the lowest-level EMI section of the PC board layout. For additional information, please refer
to Application Note 58.
CLOCK ACCURACY (PowerCap MODULE)
The DS1556 and DS9034PCX are each individually tested for accuracy. Once mounted together, the
module will typically keep time accuracy to within
±1.53 minutes per month (35 ppm) at 25°C. The
electrical environment also affects clock accuracy, and caution should be taken to place the RTC in the
lowest-level EMI section of the PC board layout. For additional information, please refer to
Application Note 58.
FREQUENCY TEST MODE
The DS1556 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 1FFF7h = 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 that requires a pullup resistor for
proper operation. The FT bit is cleared to a 0 on power-up.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1556W-120 | REAL TIME CLOCK, DMA32 |
| DS1556 | REAL TIME CLOCK, DMA32 |
| DS1556P | REAL TIME CLOCK, DMA34 |
| DS1557WP-120 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1557P-70 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1556-70+ | 功能描述:实时时钟 1M 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 |
| DS1556-70IND | 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 |
| DS1556-70IND+ | 功能描述:实时时钟 1M 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 |
| DS1556-70-W | 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 |
| DS1556P | 制造商:未知厂家 制造商全称:未知厂家 功能描述:1MEG NV Y2KC Real Time Clocks RAM |
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