參數(shù)資料
型號(hào): LM89
廠商: National Semiconductor Corporation
元件分類: 溫度/濕度傳感器
英文描述: 【0.75∑C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire Interface
中文描述: 【0.75ΣC準(zhǔn)確,遠(yuǎn)程二極管和本地?cái)?shù)字溫度傳感器兩線接口
文件頁數(shù): 9/20頁
文件大?。?/td> 745K
代理商: LM89
1.0 Functional Description
(Continued)
1.
2.
Master Senses SMBus alert line low
Master sends a START followed by the Alert Response
Address (ARA) with a Read Command.
Alerting Device(s) send ACK.
Alerting Device(s) send theirAddress. While transmitting
their address, alerting devices sense whether their ad-
dress has been transmitted correctly. (The LM89 will
reset its ALERT output and set theALERT mask bit once
its complete address has been transmitted successfully.)
Master/slave NoACK
Master sends STOP
Master attends to conditions that caused the ALERT to
be triggered. The STATUS REGISTER is read and fan
started, setpoint limits adjusted, etc.
Master resets the ALERT mask (D7 in the Configuration
register).
The ARA, 000 1100, is a general call address. No device
should ever be assigned this address.
Bit D0 (the ALERT configure bit) in the FILTER and ALERT
CONFIGURE REGISTER (xBF) must be set low in order for
the LM89 to respond to the ARA command.
The ALERT output can be disabled by setting the ALERT
mask bit, D7, of the Configuration register. The power-on-
default is to have the ALERT mask bit and the ALERT
configure bit low.
3.
4.
5.
6.
7.
8.
1.3 T_CRIT_A OUTPUT and T_CRIT LIMIT
T_CRIT_A is activated when any temperature reading is
greater than the limit preset in the critical temperature set-
point register (T_CRIT), as shown in
Figure 6
. The Status
Register can be read to determine which event caused the
alarm. A bit in the Status Register is set high to indicate
which temperature reading exceeded the T_CRIT setpoint
temperature and caused the alarm, see Section 2.3.
Local and remote temperature diodes are sampled in se-
quence by the A/D converter. The T_CRIT_A output and the
Status Register flags are updated after every Local and
Remote temperature conversion. T_CRT_A follows the state
of the comparison, it is reset when the temperature falls
below the setpoint RCS-TH. The Status Register flags are
reset only after the Status Register is read and if a tempera-
ture conversion(s) is/are below the T_CRIT setpoint, as
shown in
Figure 6
.
1.4 POWER-ON-DEFAULT STATES
LM89 always powers up to these known default states. The
LM89 remains in these states until after the first conversion.
1.
Command Register set to 00h
2.
Local Temperature set to 0C
3.
Remote Diode Temperature set to 0C until the end of
the first conversion.
4.
Status Register set to 00h.
5.
Configuration register set to 00h; ALERT enabled, Re-
mote T_CRIT alarm enabled and Local T_CRIT alarm
enabled
6.
85C Local T_CRIT temperature setpoint
7.
110C Remote T_CRIT temperature setpoint
8.
70C Local and Remote HIGH temperature setpoints
9.
0C Local and Remote LOW temperature setpoints
10. Filter and Alert Configure Register set to 00h; filter dis-
abled, ALERT output set as an SMBus ALERT
11. Conversion Rate Register set to 8h; conversion rate set
to 16 conv./sec.
1.5 SMBus INTERFACE
The LM89 operates as a slave on the SMBus, so the
SMBCLK line is an input and the SMBData line is bi-
directional. The LM89 never drives the SMBCLK line and it
does not support clock stretching. According to SMBus
specifications, the LM89 has a 7-bit slave address.All bitsA6
through A0 are internally programmed and can not be
changed by software or hardware. The LM89 and LM89-1
versions have the following SMBus slave addresses:
Version
LM89
LM89-1
A6
1
1
A5
0
0
A4
0
0
A3
1
1
A2
1
1
A1
0
0
A0
0
1
1.6 TEMPERATURE DATA FORMAT
Temperature data can only be read from the Local and
Remote
Temperature
registers;
(T_CRIT, LOW, HIGH) are read/write.
Remote temperature data is represented by an 11-bit, two’s
complement word with an LSB (Least Significant Bit) equal
to 0.125C. The data format is a left justified 16-bit word
the
setpoint
registers
20041529
FIGURE 5. ALERT Output as an SMBus ALERT
Temperature Response Diagram
20041506
FIGURE 6. T_CRIT_A Temperature Response Diagram
L
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LM89-1CIM/NOPB 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
LM89-1CIMM 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
LM89-1CIMM/NOPB 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
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