參數(shù)資料
型號(hào)： DS1921
英文描述： High-Resolution Thermochron iButton
中文描述： 高分辨率Thermochron iButton的
文件頁(yè)數(shù)： 30/44頁(yè)
文件大小： 271K
代理商： DS1921
DS1921H/Z
30 of 44
INITIALIZATION PROCEDURE (RESET AND PRESENCE PULSES)
Figure 14
MASTER TX RESET PULSE
RESISTOR
MASTER
DS1921H/Z
t
RSTL
t
PDL
t
RSTH
t
PDH
MASTER RX PRESENCE PULSE
V
PUP
V
IHMASTER
V
TH
V
TL
V
ILMAX
0V
ε
t
F
t
REC
t
MSP
After the bus master has released the line it goes into receive mode (RX). Now, the 1-Wire bus is pulled
to V
PUP
via the pull-up resistor or, in case of a DS2480B driver, by active circuitry. When the threshold
V
TH
is crossed, the DS1921H/Z waits for t
PDH
and then transmits a presence pulse by pulling the line low
for t
PDL
. To detect a presence pulse, the master must test the logical state of the 1-Wire line at t
MSP
.
The t
RSTH
window must be at least the sum of t
PDHMAX
, t
PDLMAX
, and t
RECMIN
. Immediately after t
RSTH
is
expired, the DS1921H/Z is ready for data communication. In a mixed population network, t
RSTH
should
be extended to minimum 480μs at standard speed and 48μs at Overdrive speed to accommodate other 1-
Wire devices.
Read/Write Time Slots
Data communication with the DS1921H/Z takes place in time slots that carry a single bit each. Write time
slots transport data from bus master to slave. Read time-slots transfer data from slave to master. The
definitions of the write and read time slots are illustrated in Figure 15.
All communication begins with the master pulling the data line low. As the voltage on the 1-Wire line
falls below the threshold V
TL
, the DS1921H/Z starts its internal timing generator that determines when
the data line will be sampled during a write time slot and how long data will be valid during a read time
slot.
Master to Slave
For a
write-one
time slot, the voltage on the data line must have crossed the V
TH
threshold after the
write-one low time t
W1LMAX
is expired. For a
write-zero
time slot, the voltage on the data line must stay
below the V
TH
threshold until the write-zero low time t
W0LMIN
is expired. The voltage on the data line
should not exceed V
ILMAX
during the entire t
W0L
or t
W1L
window. After the V
TH
threshold has been
crossed, the DS1921H/Z needs a recovery time t
REC
before it is ready for the next time slot.
相關(guān)PDF資料
PDF描述
DS1921H-F5 High-Resolution Thermochron iButton
DS1921Z-F5 High-Resolution Thermochron iButton
DS1963L-F5 NVRAM (Battery Based)
DS1963S SHA iButton
DS1971 256-Bit EEPROM iButton
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1921G 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Thermochron iButton
DS1921G_11 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Logs Up to 2048 Consecutive Temperature Thermochron iButton
DS1921G_1109 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Thermochron iButton
DS1921G_12 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Thermochron iButton
DS1921G-F5 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
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*