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參數(shù)資料
| 型號(hào)： | DS1996L-F5 |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Memory IC:Other |
| 英文描述： | SPECIALTY MEMORY CIRCUIT, MADB2 |
| 封裝： | MICRO CAN |
| 文件頁數(shù)： | 11/18頁 |
| 文件大小： | 321K |
| 代理商： | DS1996L-F5 |
DS1996
2 of 18
iButton DESCRIPTION
The DS1996 Memory iButton is a rugged read/write data carrier that acts as a localized database that can
be easily accessed with minimal hardware. The nonvolatile memory offers a simple solution to storing
and retrieving vital information pertaining to the object to which the iButton is attached. Data is
transferred serially via the 1-Wire protocol which requires only a single data lead and a ground return.
The scratchpad is an additional page that acts as a buffer when writing to memory. Data is first written to
the scratchpad where it can be read back. After the data has been verified, a copy scratchpad command
will transfer the data to memory. This process ensures data integrity when modifying the memory. A 48-
bit serial number is factory lasered into each DS1996 to provide a guaranteed unique identity which
allows for absolute traceability. The durable MicroCan package is highly resistant to environmental
hazards such as dirt, moisture, and shock. Its compact button-shaped profile is self-aligning with mating
receptacles, allowing the DS1996 to be easily used by human operators. Accessories permit the DS1996
to be mounted on almost any surface including plastic key fobs, photo-ID badges and printed circuit
boards. Applications include access control, work-in-progress tracking, electronic travelers, storage of
calibration constants, and debit tokens.
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of
the DS1996. The DS1996 has three main data components: 1) 64-bit lasered ROM, 2) 256-bit scratchpad
and 3) 65536-bit SRAM. The hierarchial structure of the 1-Wire protocol is shown in Figure 2. The bus
master must first provide one of the six ROM Function Commands, 1)Read ROM, 2) Match ROM, 3)
Search ROM, 4) Skip ROM, 5) Overdrive-Skip ROM or Overdrive-Match ROM. Upon completion of an
overdrive ROM command byte executed at standard speed, the device will enter Overdrive mode where
all subsequent communication occurs at a higher speed. The protocol required for these ROM Function
Commands is described in Figure 9. After a ROM Function Command is successfully executed, the
memory functions become accessible and the master may provide any one of the four memory function
commands. The protocol for these memory function commands is described in Figure 7. All data read and
written least significant bit first.
PARASITE POWER
The block diagram (Figure 1) shows the parasite-powered circuitry. This circuitry ”steals” power
whenever the data line is high. The data line will provide sufficient power as long as the specified timing
and voltage requirements are met. The advantages of parasite power are two-fold: 1) by parasiting off this
input, lithium is conserved and 2) if the lithium is exhausted for any reason, the ROM may still be read
normally.
64-BIT LASERED ROM
Each DS1996 contains a unique ROM code that is 64 bits long. The first eight bits are a 1-Wire family
code. The next 48 bits are a unique serial number. The last eight bits are a CRC of the first 56 bits.
(Figure 3.)
The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and XOR gates
as shown in Figure 4. The polynomial is X
8 + X5 + X4 + 1. Additional information about the Dallas 1-
Wire Cyclic Redundancy Check is available in the Book of DS19xx iButton Standards.
The shift register bits are initialized to zero. Then starting with the least significant bit of the family code,
one bit at a time is shifted in. After the 8
th bit of the family code has been entered, then the serial number
is entered. After the 48
th bit of the serial number has been entered, the shift register contains the CRC
value. Shifting in the eight bits of CRC should return the shift register to all zeros.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1996L-F5/A18 | 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1996L-F5+ | 功能描述:iButton 64Kb Memory iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS-19P | 制造商:Pan Pacific 功能描述: |
| DS-19S | 制造商:Pan Pacific 功能描述: |
| DS1-A | 制造商:Sliger Designs, Inc. 功能描述:CPC CASE W/ POWER SUPPLY (SPI220LE) FANS, SWITCH ECT. - Bulk |
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