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参数资料
| 型号： | DS1644P |
| 厂商： | DALLAS SEMICONDUCTOR |
| 元件分类： | Timer or RTC |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| 封装： | POWERCAP MODULE-34 |
| 文件页数： | 4/11页 |
| 文件大小： | 178K |
| 代理商： | DS1644P |
DS1644/DS1644P
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ORDERING INFORMATION
DS1644
28-pin DIP module
*DS1644P
34-pin PowerCap Module
Board
*DS9034PCX
(Power Cap) Required;
must be ordered separately
DESCRIPTION
The DS1644 is a 32k x 8 nonvolatile static RAM with a full function real time clock, which are both
accessible in a byte-wide format. The nonvolatile timekeeping RAM is function equivalent to any JEDEC
standard 32k x 8 SRAM. The device can also be easily substituted for ROM, EPROM and EEPROM,
providing read/write nonvolatility and the addition of the real time clock function. The real time clock
information resides in the eight uppermost RAM locations. The RTC registers contain year, month, date,
day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the day of the month and
leap year are made automatically. The RTC clock registers are double-buffered to avoid access of
incorrect data that can occur during clock update cycles. The double-buffered system also prevents time
loss as the timekeeping countdown continues unabated by access to time register data. The DS1644 also
contains its own power-fail circuitry, which deselects the device when the VCC supply is in an out-of-
tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by
low VCC as errant access and update cycles are avoided.
PACKAGES
The DS1644 is available in two packages (28-pin DIP and 34-pin PowerCap module). The 28-pin DIP
style module integrates the crystal, lithium energy source, and silicon all in one package. The 34-pin
PowerCap Module Board is designed with contacts for connection to a separate PowerCap (DS9034PCX)
that contains the crystal and battery. This design allows the PowerCap to be mounted on top of the
DS1644P after the completion of the surface-mount process. Mounting the PowerCap after the surface
mount process prevents damage to the crystal and battery due to the high temperatures required for solder
reflow. The PowerCap is keyed to prevent reverse insertion. The PowerCap Module Board and PowerCap
are ordered separately and shipped in separate containers. The part number for the PowerCap is
DS9034PCX.
CLOCK OPERATIONS - READING THE CLOCK
While the double-buffered register structure reduces the chance of reading incorrect data, internal updates
to the DS1644 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 1 is written into the read bit, the 7th most significant bit in the control register.
As long as a 1 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 present 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 DS1644 registers are updated simultaneously after the clock
status is reset. Updating is within a second after the read bit is written to 0.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1644 | 0 TIMER(S), REAL TIME CLOCK, DMA28 |
| DS1646-120 | 0 TIMER(S), REAL TIME CLOCK, DMA32 |
| DS1646P-120 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1646L-120 | 0 TIMER(S), REAL TIME CLOCK, DSO34 |
| DS1646 | 0 TIMER(S), REAL TIME CLOCK, DMA32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1644P+120 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P-120 | 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 |
| DS1644P120+ | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P-120+ | 功能描述:实时时钟 NV Timekeeping 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 |
| DS1644P-150 | 制造商:Maxim Integrated Products 功能描述: |
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