- 您现在的位置：买卖IC网 > Datasheet目录222 > DS1990R-F5# (Maxim Integrated)IBUTTON SERIAL NUMBER F5 Datasheet资料下载
参数资料
| 型号： | DS1990R-F5# |
| 厂商： | Maxim Integrated |
| 文件页数： | 4/10页 |
| 文件大小： | 0K |
| 描述： | IBUTTON SERIAL NUMBER F5 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| RoHS指令信息： | IButton RoHS Compliance Plan |
| 标准包装： | 73 |
| 系列： | iButton® |
| 存储容量： | 8B |
| 存储器类型： | ROM |
| 产品目录页面： | 1431 (CN2011-ZH PDF) |
Serial Number iButton
64-Bit Lasered ROM
Each DS1990R contains a unique ROM code that is 64
bits long. The first 8 bits are a 1-Wire family code. The
next 48 bits are a unique serial number. The last 8 bits
are a CRC of the first 56 bits. See Figure 2 for details.
The 1-Wire CRC is generated using a polynomial gen-
erator consisting of a shift register and XOR gates as
shown in Figure 3. The polynomial is X 8 + X 5 + X 4 + 1.
Additional information about the 1-Wire Cyclic
Redundancy Check (CRC) is available in Application
Note 27: Understanding and Using Cyclic Redundancy
Checks with Maxim iButton Products.
The shift register bits are initialized to 0. Then starting
with the least significant bit of the family code, one bit
at a time is shifted in. After the 8th bit of the family code
has been entered, the serial number is entered. After
the 48th bit of the serial number has been entered, the
shift register contains the CRC value. Shifting in the 8
bits of CRC returns the shift register to all 0s.
MSB
1-Wire Bus System
The 1-Wire bus is a system that has a single bus master
and one or more slaves. In all instances, the DS1990R
is a slave device. The bus master is typically a micro-
controller or PC. For small configurations, the 1-Wire
communication signals can be generated under soft-
ware control using a single port pin. Alternatively, the
DS2480B 1-Wire line driver chip or serial-port adapters
based on this chip (DS9097U series) can be used. This
simplifies the hardware design and frees the micro-
processor from responding in real time. The discussion
of this bus system is broken down into three topics:
hardware configuration, transaction sequence, and
1-Wire signaling (signal types and timing). The 1-Wire
protocol defines bus transactions in terms of the bus
state during specific time slots that are initiated on the
falling edge of sync pulses from the bus master. For a
more detailed protocol description, refer to Chapter 4 of
the Application Note 937: Book of iButton Standards.
LSB
8-BIT
CRC CODE
48-BIT SERIAL NUMBER
8-BIT FAMILY CODE
(01h)
MSB
LSB MSB
LSB MSB
LSB
Figure 2. 64-Bit Lasered ROM
POLYNOMIAL = X 8 + X 5 + X 4 + 1
1ST
STAGE
2ND
STAGE
3RD
STAGE
4TH
STAGE
5TH
STAGE
6TH
STAGE
7TH
STAGE
8TH
STAGE
X 0
X 1
X 2
X 3
X 4
X 5
X 6
X 7
X 8
INPUT DATA
Figure 3. 1-Wire CRC Generator
4
_______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| DS1993L-F5+ | IBUTTON MEMORY 4KBit F5 |
| DS1995L-F5+ | IBUTTON MEMORY 16KBit F5 |
| DS1996L-F5+ | IBUTTON MEMORY 64KBit F5 |
| DS9092K# | KIT IBUTTON STARTER |
| DS9502P+T&R | DIODE ESD PROTECTION 6-TSOC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1990R-F5# | 功能描述:序列号注册 Serial Number iButton RoHS:否 制造商:Maxim Integrated 数据总线宽度: 电源电压-最大: 电源电压-最小: 最大工作温度: 最小工作温度: 安装风格: 封装 / 箱体: |
| DS1990R-F5+W | 功能描述:序列号注册 RoHS:否 制造商:Maxim Integrated 数据总线宽度: 电源电压-最大: 电源电压-最小: 最大工作温度: 最小工作温度: 安装风格: 封装 / 箱体: |
| DS1990-序列号IBUTTON | 制造商:未知厂家 制造商全称:未知厂家 功能描述: |
| DS1991 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:MultiKey iButton |
| DS1991L | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
发布紧急采购，3分钟左右您将得到回复。