參數(shù)資料
型號: DS9101
英文描述: RTC iButton
中文描述: 多用途夾子
文件頁數(shù): 9/12頁
文件大小: 72K
代理商: DS9101
DS1904
9 of 12
Skip ROM [CCh]
This command can save time in a single drop bus system by allowing the bus master to access the clock
functions without providing the 64-bit ROM code. If more than one slave is present on the bus and, for
example, a read command is issued following the Skip ROM command, data collision will occur on the
bus as multiple slaves transmit simultaneously (open drain pull-downs will produce a wired-AND result).
1–WIRE SIGNALING
The DS1904 requires strict protocols to ensure data integrity. The protocol consists of four types of sig-
naling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write 0, Write 1 and Read Data.
Except for the presence pulse the bus master initiates all these signals.
The initialization sequence required to begin any communication with the DS1904 is shown in Figure 8.
A reset pulse followed by a presence pulse indicates the DS1904 is ready to send or receive data. The bus
master transmits (TX) a reset pulse (t
RSTL
, minimum 480
μ
s). The bus master then releases the line and
goes into receive mode (RX). The 1-Wire bus is pulled to a high state via the pull-up resistor. After
detecting the rising edge on the data line, the DS1904 waits (t
PDH
, 15-60
μ
s) and then transmits the
presence pulse (t
PDL
, 60-240
μ
s).
INITIALIZATION PROCEDURE “RESET AND PRESENCE PULSES”
Figure 8
MASTER TX
"RESET PULSE"
V
PULLUP
V
PULLUP MIN
V
IH MIN
RESISTOR
MASTER
DS1904
MASTER RX "PRESENCE PULSE"
480 μs
t
RSTL
<
*
480 μs
t
RSTH
<
**
15 μs
t
PDH
< 60 μs
60
t
PDL
< 240 μs
V
IL MAX
0V
t
RSTH
t
RSTL
t
PDH
t
PDL
t
R
*
In order not to mask interrupt signaling by other devices on the 1-Wire bus t
RSTL
+ t
R
should al-
ways be less than 960 μs.
Includes recovery time
**
READ/WRITE TIME SLOTS
The definitions of write and read time slots are illustrated in Figure 9. The master initiates all time slots
by driving the data line low. The falling edge of the data line synchronizes the DS1904 to the master by
triggering an internal delay circuit. During write time slots, the delay circuit determines when the DS1904
will sample the data line. For a read data time slot, if a “0” is to be transmitted, the delay circuit deter-
mines how long the DS1904 will hold the data line low. If the data bit is a “1”, the DS1904 will not hold
the data line low at all.
相關(guān)PDF資料
PDF描述
DS9097U Universal 1-Wire COM Port Adapter
DS9097U-E25 Universal 1-Wire COM Port Adapter
DS90C032N Line Receiver
DS90C032TMX Line Receiver
DS90C363MTDX Video Link Interface
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS9101/NO-BRAND 功能描述:iButton配件 RoHS:否 產(chǎn)品:iButton Probes 用于:DS19xx Series 制造商:Maxim Integrated
DS9101+ 功能描述:iButton配件 IButton Multipurpose Clip RoHS:否 產(chǎn)品:iButton Probes 用于:DS19xx Series 制造商:Maxim Integrated
DS9104 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Digital Decoder Ring
DS9104-060 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Digital Decoder Ring
DS9104-065 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Digital Decoder Ring