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參數(shù)資料
| 型號： | DS17887-5 |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Timer or RTC |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, DMA24 |
| 封裝： | PLASTIC, MODULE, DIP-24 |
| 文件頁數(shù)： | 8/38頁 |
| 文件大小： | 407K |
| 代理商： | DS17887-5 |
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DS17885/DS17887
16 of 38
EXTENDED FUNCTIONS
The extended functions provided by the DS17885/DS17887 that are new to the RAMified RTC family
are accessed via a software controlled bank switching scheme, as illustrated in Figure 4. In bank 0, the
clock/calendar registers and 50 bytes of user RAM are in the same locations as for the DS1287. As a
result, existing routines implemented within BIOS, DOS, or application software packages can gain
access to the DS17885/DS17887 clock registers with no changes. Also in bank 0, an extra 64 bytes of
RAM are provided at addresses just above the original locations for a total of 114 directly addressable
bytes of user RAM.
When bank 1 is selected, the clock/calendar registers and the original 50 bytes of user RAM still appear
as bank 0. However, the Dallas registers which provide control and status for the extended functions will
be accessed in place of the additional 64 bytes of user RAM. The major extended functions controlled by
the Dallas registers are listed below:
1. 64-bit Silicon Serial Number
2. Century counter
3. RTC Write Counter
4. Date Alarm
5. Auxiliary Battery Control/Status
6. Wake-Up
7. Kickstart
8. RAM Clear Control/Status
9. 8-kbytes Extended RAM Access
The bank selection is controlled by the state of the DV0 bit in register A. To access bank 0 the DV0 bit
should be written to a 0. To access bank 1, DV0 should be written to a 1. Register locations designated
as reserved in the bank 1 map are reserved for future use by Dallas Semiconductor. Bits in these
locations cannot be written and will return a 0 if read.
SILICON SERIAL NUMBER
A unique 64-bit lasered serial number is located in bank 1, registers 40h - 47h. This serial number is
divided into three parts. The first byte in register 40h contains a model number to identify the device type
of the DS17885/DS17887. Registers 41h - 46h contain a unique binary number. Register 47h contains a
CRC byte used to validate the data in registers 40h - 46h. All 8 bytes of the serial number are read-only
registers.
The DS17885/DS17887 is manufactured such that no two devices will contain an identical number in
locations 41h - 47h.
CENTURY COUNTER
A register has been added in bank 1, location 48H, to keep track of centuries. The value is read in either
binary or BCD according to the setting of the DM bit.
RTC WRITE COUNTER
An 8-bit counter located in extended register bank 1, 5Eh, will count the number of times the RTC is
written to. This counter will be incremented on the rising edge of the WR signal every time that the CS
signal qualifies it. This counter is a read-only register and will roll-over after 256 RTC write pulses. This
counter can be used to determine if and how many RTC writes have occurred since the last time this
register was read.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS17885-3 | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| DS17885S-5 | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| DS17885E-5 | 1 TIMER(S), REAL TIME CLOCK, PDSO28 |
| DS1821+ | DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 1Cel, RECTANGULAR, SURFACE MOUNT |
| DS1821S+ | DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 1Cel, RECTANGULAR, SURFACE MOUNT |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS17887-5 IND | 功能描述:實時時鐘 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 |
| DS17887-5+ | 功能描述:實時時鐘 3V/5V RTC 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 |
| DS17887-5IND | 功能描述:IC RTC 5V 8K NV RAM 24-EDIP RoHS:否 類別:集成電路 (IC) >> 時鐘/計時 - 實時時鐘 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 類型:時鐘/日歷 特點:警報器，閏年，SRAM 存儲容量:- 時間格式:HH:MM:SS（12/24 小時） 數(shù)據(jù)格式:YY-MM-DD-dd 接口:SPI 電源電壓:2 V ~ 5.5 V 電壓 - 電源，電池:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-WDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-TDFN EP 包裝:管件 |
| DS17887-5IND+ | 功能描述:實時時鐘 3V/5V RTC 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 |
| DS17H531D | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:3-PHASE STEPPING SYSTEMS |
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