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參數(shù)資料
| 型號： | DS1821 |
| 元件分類： | 溫度傳感器 |
| 英文描述： | Programmable Digital Thermostat |
| 文件頁數(shù)： | 10/16頁 |
| 文件大小： | 570K |
| 代理商： | DS1821 |
DS1821
10 of 16
READ/WRITE TIME SLOTS
DS1821 data is read and written through the use of time slots to manipulate bits and a command word to
specify the transaction.
Write Time Slots
A write time slot is initiated when the host pulls the data line from a high logic level to a low logic level.
There are two types of write time slots: Write 1 time slots and Write 0 time slots. All write time slots
must be a minimum of 60
μ
s in duration with a minimum of a 1-
μ
s recovery time between individual
write cycles.
The DS1821 samples the DQ line in a window of 15
μ
s to 60
μ
s after the DQ line falls. If the line is high,
a Write 1 occurs. If the line is low, a Write 0 occurs (see Figure 6).
For the host to generate a Write 1 time slot, the data line must be pulled to a logic low level and then
released, allowing the data line to pull up to a high level within 15 microseconds after the start of the
write time slot.
For the host to generate a Write 0 time slot, the data line must be pulled to a logic low level and remain
low for the duration of the write time slot.
Read Time Slots
The host generates read time slots when data is to be read from the DS1821. A read time slot is initiated
when the host pulls the data line from a logic high level to logic low level. The data line must remain at a
low logic level for a minimum of 1 μs; output data from the DS1821 is then valid for the next 14 μs
maximum. The host therefore must stop driving the DQ pin low in order to read its state 15 μs from the
start of the read slot (see Figure 6). By the end of the read time slot, the DQ pin will pull back high via the
external pullup resistor. All read time slots must be a minimum of 60 μs in duration with a minimum of a
one μs recovery time between individual read slots.
Figure 7 shows that the sum of T
INIT
, T
RC
, and T
SAMPLE
must be less than 15 μs. Figure 8 shows that
system timing margin is maximized by keeping T
INIT
and T
RC
as small as possible and by locating the
master sample time towards the end of the 15-μs period.
INITIALIZATION PROCEDURE “RESET AND PRESENCE PULSES”
Figure 5
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1830 | Reset Sequence Pushbutton |
| DS1830A | Reset Sequence Pushbutton |
| DS1830AS | Reset Sequence Pushbutton |
| DS1830AU | Reset Sequence Pushbutton |
| DS1830U | Reset Sequence Pushbutton |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1821_07 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Programmable Digital Thermostat and Thermometer |
| DS1821+ | 功能描述:板上安裝溫度傳感器 Programmable Digital Thermostat/Thrmmtr 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 |
| DS1821C+ | 功能描述:恒溫器 Programmable Digital Thermo-stat/monitor RoHS:否 制造商:Maxim Integrated 功能: 開路溫度: 閉合溫度: 準(zhǔn)確性:+/- 1 C 溫度范圍:- 55 C to + 125 C 電流額定值:500 uA 電壓額定值:2.7 V to 5.5 V 產(chǎn)品:Thermostats |
| DS1821-C02 | 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 |
| DS1821-C04 | 制造商:DSC 功能描述: |
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