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參數(shù)資料
| 型號(hào)： | ADM1021A |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Low-Cost Microprocessor System Temperature Monitor |
| 中文描述： | 低成本的微處理器系統(tǒng)溫度監(jiān)控 |
| 文件頁(yè)數(shù)： | 10/12頁(yè) |
| 文件大?。?/td> | 163K |
| 代理商： | ADM1021A |
ADM1021A
–10–
REV. A
2. Data is sent over the serial bus in sequences of nine clock
pulses, eight bits of data followed by an Acknowledge Bit
from the slave device. Transitions on the data line must occur
during the low period of the clock signal and remain stable
during the high period, as a low-to-high transition when the
clock is high may be interpreted as a STOP signal. The num-
ber of data bytes that can be transmitted over the serial bus
in a single READ or WRITE operation is limited only by
what the master and slave devices can handle.
3. When all data bytes have been read or written, stop conditions
are established. In WRITE mode, the master will pull the data
line high during the 10th clock pulse to assert a STOP condi-
tion. In READ mode, the master device will override the
acknowledge bit by pulling the data line high during the low
period before the ninth clock pulse. This is known as No
Acknowledge. The master will then take the data line low
during the low period before the 10th clock pulse, then high
during the 10th clock pulse to assert a STOP condition.
Any number of bytes of data may be transferred over the serial
bus in one operation, but it is not possible to mix read and write
in one operation, because the type of operation is determined at
the beginning and cannot subsequently be changed without
starting a new operation.
In the case of the ADM1021A, write operations contain either
one or two bytes, while read operations contain one byte and
perform the following functions:
To write data to one of the device data registers or read data
from it, the Address Pointer Register must be set so that the
correct data register is addressed, data can then be written into
that register or read from it. The first byte of a write operation
always contains a valid address that is stored in the Address
Pointer Register. If data is to be written to the device, the write
operation contains a second data byte that is written to the reg-
ister selected by the address pointer register.
This is illustrated in Figure 13. The device address is sent over
the bus followed by R/
W
set to 0. This is followed by two data
bytes. The first data byte is the address of the internal data reg-
ister to be written to, which is stored in the Address Pointer
Register. The second data byte is the data to be written to the
internal data register.
When reading data from a register there are two possibilities:
1. If the ADM1021A’s Address Pointer Register value is unknown
or not the desired value, it is first necessary to set it to the
correct value before data can be read from the desired data
register. This is done by performing a write to the ADM1021A
as before, but only the data byte containing the register read
address is sent, as data is not to be written to the register.
This is shown in Figure 14.
A read operation is then performed consisting of the serial
bus address, R/
W
bit set to 1, followed by the data byte read
from the data register. This is shown in Figure 15.
2. If the Address Pointer Register is known to be already at the
desired address, data can be read from the corresponding
data register without first writing to the Address Pointer
Register, so Figure 14 can be omitted.
NOTES
1. Although it is possible to read a data byte from a data register
without first writing to the Address Pointer Register, if the
Address Pointer Register is already at the correct value, it is
not possible to write data to a register without writing to the
Address Pointer Register, because the first data byte of a
write is always written to the Address Pointer Register.
2. Remember that the ADM1021A registers have different
addresses for read and write operations. The write address of
a register must be written to the Address Pointer if data is to
be written to that register, but it is not possible to read data
from that address. The read address of a register must be
written to the Address Pointer before data can be read from
that register.
ALERT OUTPUT
The
ALERT
output goes low whenever an out-of limit mea-
surement is detected, or if the remote temperature sensor is
open-circuit. It is an open-drain and requires a 10 k
pull-up to
V
DD
. Several
ALERT
outputs can be wire-ANDED together, so
that the common line will go low if one or more of the
ALERT
outputs goes low.
The
ALERT
output can be used as an interrupt signal to a pro-
cessor, or it may be used as an
SMBALERT
. Slave devices on
the SMBus can normally not signal to the master that they want
to talk, but the
SMBALERT
function allows them to do so.
One or more
ALERT
outputs are connected to a common
SMBALERT
line connected to the master. When the
SMBALERT
line is pulled low by one of the devices, the following procedure
occurs as illustrated in Figure 16.
MASTER
SMBALERT
ARA AND READ
COMMAND
DEVICE SENDS
ITS ADDRESS
NO
ACK
START
ALERT RESPONSE ADDRESS
RD
ACK
DEVICE ADDRESS
STOP
Figure 16. Use of
SMBALERT
1.
SMBALERT
pulled low.
2. Master initiates a read operation and sends the Alert Response
Address (ARA = 0001 100). This is a general call address
that must not be used as a specific device address.
3. The device whose
ALERT
output is low responds to the
Alert Response Address and the master reads its device
address. The address of the device is now known and it can
be interrogated in the usual way.
4. If more than one device’s
ALERT
output is low, the one with
the lowest device address, will have priority, in accordance with
normal SMBus arbitration.
5. Once the ADM1021A has responded to the Alert Response
Address, it will reset its
ALERT
output, provided that the
error condition that caused the
ALERT
no longer exists. If
the
SMBALERT
line remains low, the master will send ARA
again, and so on until all devices whose
ALERT
outputs were
low have responded.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
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| ADM1021AARQ | 功能描述:IC SENSOR TEMP DUAL3/5.5V 16QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應(yīng)溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠(yuǎn)程（最大值） 拓?fù)?ADC，比較器，寄存器庫(kù) 輸出類型:2 線 SMBus? 輸出警報(bào):無 輸出風(fēng)扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應(yīng)商設(shè)備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6 |
| ADM1021AARQ-REEL | 功能描述:IC SENSOR TEMP DUAL3/5.5V 16QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應(yīng)溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠(yuǎn)程（最大值） 拓?fù)?ADC，比較器，寄存器庫(kù) 輸出類型:2 線 SMBus? 輸出警報(bào):無 輸出風(fēng)扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應(yīng)商設(shè)備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6 |
| ADM1021AARQ-REEL7 | 功能描述:IC SENSOR TEMP DUAL3/5.5V 16QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應(yīng)溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠(yuǎn)程（最大值） 拓?fù)?ADC，比較器，寄存器庫(kù) 輸出類型:2 線 SMBus? 輸出警報(bào):無 輸出風(fēng)扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應(yīng)商設(shè)備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6 |
| ADM1021AARQZ | 功能描述:板上安裝溫度傳感器 PIN COMP TO ADM1021 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 |
| ADM1021AARQZ-R | 功能描述:板上安裝溫度傳感器 PIN COMP TO ADM1021 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 |
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