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參數(shù)資料
| 型號： | DS1647-120 |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Timer or RTC |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, DMA28 |
| 封裝： | MODULE, DIP-28 |
| 文件頁數(shù)： | 4/11頁 |
| 文件大小： | 370K |
| 代理商： | DS1647-120 |
DS1647/DS1647P
2 of 11
PIN DESCRIPTION
A0-A18
- Address Input
CE
- Chip Enable
OE
- Output Enable
WE
- Write Enable
VCC
- +5 Volts
GND
- Ground
DQ0-DQ7
- Data Input/Output
NC
- No Connection
PFO
- Power-fail Output
(DS1647P only)
X1, X2
- Crystal Connection
VBAT
- Battery Connection
DESCRIPTION
The DS1647 is a 512k x 8 nonvolatile static RAM with a full function real time clock which are both
accessible in a Byte-wide format. The nonvolatile time keeping RAM is function equivalent to any
JEDEC standard 512k 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 DS1647
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 DS1647 is available in two packages (32-pin DIP module and 34-pin PowerCap module). The 32-pin
Dip style module integrated 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. The design allows the PowerCap to be mounted on top of the
DS1647P 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 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 DS1647 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 one is written into the read bit, the seventh most significant bit in the control
register. As long as a one 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 current 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 DS1647 registers are updated simultaneously
after the clock status is reset. Updating is within a second after the read bit is written to zero.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1647P-120 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1647P | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1647 | 0 TIMER(S), REAL TIME CLOCK, DMA32 |
| DS1670 | 0 TIMER(S), REAL TIME CLOCK, PDSO20 |
| DS1672-2 | 0 TIMER(S), REAL TIME CLOCK, PDIP8 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1647-120+ | 功能描述:實時時鐘 NV Timekeeping RAM 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1647-15 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:NVRAM (Battery Based) |
| DS1647D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Bus Transceiver |
| DS1647L-12 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:NVRAM (Battery Based) |
| DS1647L-15 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:NVRAM (Battery Based) |
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