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參數(shù)資料
| 型號(hào)： | DS2422 |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | DRAM |
| 英文描述： | 1K-Bit 1-Wire RAM with Counters(帶計(jì)數(shù)器的1K位1線串行RAM) |
| 中文描述： | 1K X 1 STANDARD SRAM, PDSO6 |
| 封裝： | 3.70 X 4 X 1.50 MM, TSOC-6 |
| 文件頁數(shù)： | 13/23頁 |
| 文件大小： | 146K |
| 代理商： | DS2422 |
DS2422/DS2423
021998 13/23
HARDWARE CONFIGURATION
Figure 8
V
PUP
DS242X 1–WIRE PORT
R
X
T
X
100 OHM
MOSFET
5 k
TYP.
R
X
T
X
R
X
=
RECEIVE
T
X
=
TRANSMIT
5
μ
A
TYP.
BUS MASTER
DATA
OPEN DRAIN
PORT PIN
1–WIRE BUS SYSTEM
The 1–Wire bus is a system which has a single bus mas-
ter and one or more slaves. In all instances the DS242X
is a slave device. The bus master is typically a micro-
controller. The discussion of this bus system is broken
down into three topics: hardware configuration, transac-
tion sequence, and 1–Wire signaling (signal types and
timing). A 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 Book of DS19xx iButton Standards.
HARDWARE CONFIGURATION
The 1–Wire bus has only a single line by definition; it is
important that each device on the bus be able to drive it
at the appropriate time. To facilitate this, each device
attached to the 1–Wire bus must have open drain or
3–state outputs. The 1–Wire port of the DS242X is open
drain with an internal circuit equivalent to that shown in
Figure 8. A multidrop bus consists of a 1–Wire bus with
multiple slaves attached. At regular speed the 1–Wire
bus has a maximum data rate of 16.3k bits per second.
The speed can be boosted to 142k bits per second by
activating the Overdrive Mode. The 1–Wire bus
requires a pull–up resistor of approximately 5 k
.
The idle state for the 1–Wire bus is high. If for any rea-
son a transaction needs to be suspended, the bus
MUST be left in the idle state if the transaction is to
resume. If this does not occur and the bus is left low for
more than 16
μ
s (Overdrive Speed) or more than 120
μ
s
(regular speed), one or more devices on the bus may be
reset.
TRANSACTION SEQUENCE
The protocol for accessing the DS242X via the 1–Wire
port is as follows:
Initialization
ROM Function Command
Memory Function Command
Transaction/Data
INITIALIZATION
All transactions on the 1–Wire bus begin with an initial-
ization sequence. The initialization sequence consists
of a reset pulse transmitted by the bus master followed
by presence pulse(s) transmitted by the slave(s).
The presence pulse lets the bus master know that the
DS242X is on the bus and is ready to operate. For more
details, see the “1–Wire Signaling” section.
ROM FUNCTION COMMANDS
Once the bus master has detected a presence, it can
issue one of the six ROM function commands. All ROM
function commands are eight bits long. A list of these
commands follows (refer to flowchart in Figure 9):
Read ROM [33H]
This command allows the bus master to read the
DS242X’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 DS242X on the bus. If more than one
slave is present on the bus, a data collision will occur
when all slaves try to transmit at the same time (open
drain will produce a wired–AND result). The resultant
family code and 48–bit serial number will result in a mis-
match of the CRC.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS2422P | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Serial SRAM |
| DS2422S | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| DS2422S+ | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| DS2422X | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| DS2423 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:4kbit 1-Wire RAM with Counter |
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