lm84cimqax National Semiconductor Corporation, lm84cimqax Datasheet - Page 12

• Manufacturer Part Number: lm84cimqax
• Description: Diode Input Digital Temperature Sensor With Two-wire Interface
• Manufacturer: National Semiconductor Corporation

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1.0 Functional Description
1.8 LM84 REGISTERS
1.8.1 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:
1.8.2 LOCAL and REMOTE TEMPERATURE REGISTERS
D7–D0: Temperature Data. One LSB = 1˚C. Two’s complement format.
1.8.3 STATUS REGISTER
Power up default is with all bits “0” (zero).
D2: OPEN: When set to 1 indicates a Remote Diode disconnect.
D4: RTCRIT: When set to 1 indicates an RT_CRIT alarm.
D6: LTCRIT: When set to 1 indicates an LT_CRIT alarm.
D7, D5, D3, D1–D0: These bits are always set to 0.
1.8.4 Manufacturers ID Register
(Read Address 04h) Default value 00h.
1.8.5 CONFIGURATION REGISTER
Power up default is with all bits “0” (zero).
D7: T_CRIT_A mask: When set to 1 T_CRIT_A interrupts are masked.
D6–D0: These bits are always set to 0. A write of 1 will return a 0 when read.
(Read Only Address 00h and 01h):
(Read Only Address 02h):
(Read Address 03h /Write Address 09h):
MSB
P7
Command Se-
D7
T_CRIT_A
<
0
lect Address
D7
0
P7:P0
mask
D7
0Bh
0Dh
00h
01h
02h
03h
04h
05h
07h
09h
Bit 6
P6
LTCRIT
D6
0
>
D6
hex
Bit 5
P5
0
D5
<
D6
D5
D7:D0
0
0
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0111 1111
0111 1111
0000 0000
0111 1111
0111 1111
P4
Bit 4
0
D4
Power On Default State
RTCRIT
>
binary
D4
P3
Bit 3
D3
Command Select
D5
0
P2
D3
Bit 2
<
0
D2
D7:D0
(Continued)
mal
127
127
127
127
P1
0
0
0
0
0
0
OPEN
Bit 1
>
D1
D2
deci-
D4
0
P0
LSB
D0
D1
0
12
Register Name
WRCS
RRCS
WLCS
RLCS
RMID
RRT
RLT
WC
RS
RC
D3
D0
0
0
Read Local T_CRIT Setpoint
Write Local T_CRIT Setpoint
Read Remote Temperature
Read Local Temperature
Read Remote T_CRIT
Write Remote T_CRIT
D2
0
Register Function
Read Configuration
Write Configuration
Manufacturers ID
Read Status
Setpoint
Setpoint
D1
0
D0
0