LM89CIM NSC [National Semiconductor], LM89CIM Datasheet - Page 13

• Manufacturer Part Number: LM89CIM
• Manufacturer: NSC [National Semiconductor]

1.0 Functional Description
1.12 FAULT QUEUE
In order to suppress erroneous ALERT or T_CRIT triggering
the LM89 incorporates a Fault Queue. The Fault Queue acts
to insure a remote temperature measurement is genuinely
beyond a HIGH, LOW or T_CRIT setpoint by not triggering
until three consecutive out of limit measurements have been
made, see Figure 10. The fault queue defaults off upon
power-up and may be activated by setting bit D0 in the
Configuration register (09h) to “1”.
2.0 LM89 Registers
2.1 COMMAND REGISTER
Selects which registers will be read from or written to. Data for this register should be transmitted during the Command Byte of
the SMBus write communication.
P0-P7: Command Select
Read Address
<
FIGURE 10. Fault Queue Temperature Response
P7:P0
Command Select Address
00h
01h
02h
03h
04h
05h
06h
07h
08h
10h
11h
NA
>
hex
Write Address
<
P7:P0
Diagram
0Ah
0Bh
0Ch
0Dh
0Eh
09h
0Fh
11h
NA
NA
NA
NA
>
hex
P7
<
P6
20041530
D7:D0
0000 0000
0000 0000
0000 0000
0000 0000
0000 1000
0000 0000
0000 0000
0000 0000
0000 0000
0100 0110
0100 0110
Power-On-Default State
(Continued)
>
P5
binary
Command Select
P4
13
conv./sec)
<
P3
decimal
1.13 ONE-SHOT REGISTER
The One-Shot register is used to initiate a single conversion
and comparison cycle when the device is in standby mode,
after which the device returns to standby. This is not a data
register and it is the write operation that causes the one-shot
conversion. The data written to this address is irrelevant and
is not stored. A zero will always be read from this register.
D7:D0
8 (16
70
70
0
0
0
0
0
0
0
0
P2
>
One Shot
P1
Register
RHSHB
RTOHB
RLSHB
Name
RTHB
RTLB
LHS
LLS
CR
SR
LT
C
P0
Local Temperature
Remote Temperature High Byte
Status Register
Configuration
Conversion Rate
Local HIGH Setpoint
Local LOW Setpoint
Remote HIGH Setpoint High Byte
Remote LOW Setpoint High Byte
Writing to this register will initiate a
one shot conversion
Remote Temperature Low Byte
Remote Temperature Offset High
Byte
Register Function
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