- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄376962 > DS1921 High-Resolution Thermochron iButton PDF資料下載
參數(shù)資料
| 型號： | DS1921 |
| 英文描述： | High-Resolution Thermochron iButton |
| 中文描述： | 高分辨率Thermochron iButton的 |
| 文件頁數(shù)： | 29/44頁 |
| 文件大?。?/td> | 271K |
| 代理商： | DS1921 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁當前第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁
DS1921H/Z
29 of 44
On a single-drop bus this command can save time by allowing the bus master to access the
memory/control functions without providing the 64-bit ROM code. Unlike the normal Skip ROM
command, the Overdrive Skip ROM sets the DS1921H/Z in the Overdrive mode (OD = 1). All
communication following this command has to occur at Overdrive speed until a reset pulse of minimum
480μs duration resets all devices on the bus to standard speed (OD = 0).
When issued on a multidrop bus this command will set all Overdrive-supporting devices into Overdrive
mode. To subsequently address a specific Overdrive-supporting device, a reset pulse at Overdrive speed
has to be issued followed by a Match ROM or Search ROM command sequence. This will speed up the
time for the search process. If more than one slave supporting Overdrive is present on the bus and the
Overdrive Skip ROM command is followed by a Read command, data collision will occur on the bus as
multiple slaves transmit simultaneously (open-drain pull-downs will produce a wired-AND result).
Overdrive Match ROM [69h]
The Overdrive Match ROM command followed by a 64-bit ROM sequence transmitted at Overdrive
Speed allows the bus master to address a specific DS1921H/Z on a multidrop bus and to simultaneously
set it in Overdrive mode. Only the DS1921H/Z that exactly matches the 64-bit ROM sequence will
respond to the subsequent memory/control function command. Slaves already in Overdrive mode from a
previous Overdrive Skip or successful Overdrive Match command will remain in Overdrive mode. All
overdrive-capable slaves will return to standard speed at the next Reset Pulse of minimum 480μs
duration. The Overdrive Match ROM command can be used with a single or multiple devices on the bus.
1-WIRE SIGNALING
The DS1921H/Z requires strict protocols to ensure data integrity. The protocol consists of four types of
signaling 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 DS1921H/Z can
communicate at two different speeds: standard speed and Overdrive speed. If not explicitly set into the
Overdrive mode, the DS1921H/Z will communicate at standard speed. While in Overdrive mode the fast
timing applies to all waveforms.
To get from idle to active, the voltage on the 1-Wire line needs to fall from V
PUP
below the threshold V
TL
.
To get from active to idle, the voltage needs to rise from V
ILMAX
past the threshold V
TH
. The time it takes
for the voltage to make this rise is seen in Figure 14 as ‘
ε
’ and its duration depends on the pull-up resistor
(R
PUP
) used and capacitance of the 1-Wire network attached. The voltage V
ILMAX
is relevant for the
DS1921H/Z when determining a logical level, but not for triggering any events.
The initialization sequence required to begin any communication with the DS1921H/Z is shown in Figure
14. A Reset Pulse followed by a Presence Pulse indicates the DS1921H/Z is ready to receive data, given
the correct ROM and memory function command. If the bus master uses slew-rate control on the falling
edge, it must pull down the line for t
RSTL
+ t
F
to compensate for the edge. A t
RSTL
duration of 480μs or
longer will exit the Overdrive mode returning the device to standard speed. If the DS1921H/Z is in
Overdrive mode and t
RSTL
is no longer than 80μs, the device will remain in Overdrive mode.
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 存儲類型:SRAM 存儲容量: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，3分鐘左右您將得到回復。