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参数资料
| 型号： | DS1990R-F5# |
| 厂商： | Maxim Integrated |
| 文件页数： | 6/10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
1-Wire ROM Function Commands
BUS MASTER Tx
RESET PULSE
Once the bus master has detected a presence pulse, it
can issue one of the ROM function commands the
DS1990R supports. All ROM function commands are
8 bits long. A list of these commands follows. (See
BUS MASTER Tx ROM
FUNCTION COMMAND
DS1990R Tx
PRESENCE PULSE
Figure 5 for a flowchart.)
Read ROM [33h] or [0Fh]
This command allows the bus master to read the
33h OR
0Fh READ ROM
COMMAND?
Y
N
F0h
SEARCH ROM
COMMAND?
Y
N
DS1990R’s 8-bit family code, unique 48-bit serial num-
ber, and 8-bit CRC. This command can only be used if
there is a single slave device on the bus. If more than one
slave is present on the bus, a data collision occurs when
all slaves try to transmit at the same time (open drain pro-
duces a wired-AND result). The resultant family code and
DS1990R Tx
FAMILY CODE
(1 BYTE)
DS1990R Tx
SERIAL NUMBER
(6 BYTES)
DS1990R Tx
CRC BYTE
Figure 5. ROM Functions Flowchart
N
N
N
DS1990R Tx BIT 0
DS1990R Tx BIT 0
MASTER Tx BIT 0
BIT 0 MATCH?
Y
DS1990R Tx BIT 1
DS1990R Tx BIT 1
MASTER Tx BIT 1
BIT 1 MATCH?
Y
DS1990R Tx BIT 63
DS1990R Tx BIT 63
MASTER Tx BIT 63
BIT 63 MATCH?
Y
48-bit serial number results in a mismatch of the CRC.
Search ROM [F0h]
When a system is initially brought up, the bus master
might not know the number of devices on the 1-Wire
bus or their registration numbers. By taking advantage
of the wired-AND property of the bus, the master can
use a process of elimination to identify the registration
numbers of all slave devices. For each bit of the regis-
tration number, starting with the least significant bit, the
bus master issues a triplet of time slots. On the first slot,
each slave device participating in the search outputs
the true value of its registration number bit. On the sec-
ond slot, each slave device participating in the search
outputs the complemented value of its registration num-
ber bit. On the third slot, the master writes the true
value of the bit to be selected. All slave devices that do
not match the bit written by the master stop participat-
ing in the search. If both of the read bits are zero, the
master knows that slave devices exist with both states
of the bit. By choosing which state to write, the bus
master branches in the ROM code tree. After one com-
plete pass, the bus master knows the registration num-
ber of a single device. Additional passes identify the
registration numbers of the remaining devices. Refer to
Application Note 187: 1-Wire Search Algorithm for a
detailed discussion, including an example.
Match ROM [55h]/Skip ROM [CCh]
The minimum set of 1-Wire ROM function commands
includes a Match ROM and a Skip ROM command.
Because the DS1990R contains only the 64-bit ROM
without any additional data fields, Match ROM and Skip
ROM are not applicable. The DS1990R remains silent
(inactive) upon receiving a ROM function command
that it does not support. This allows the DS1990R to
coexist on a multidrop bus with other 1-Wire devices
that do respond to Match ROM or Skip ROM.
6
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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 |
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