Rainbow Electronics LM84 - Manual (Page 12)

1.0 Functional Description
(Continued)
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.
P7 P6 P5 P4 P3 P2 P1 P0
0 0 0 0 Command Select
P0-P7: Command Select:
Command Se-
lect Address
Power On Default State Register Name Register Function
< P7:P0 > hex < D7:D0 > binary < D7:D0 > deci-
mal
00h 0000 0000 0 RLT Read Local Temperature
01h 0000 0000 0 RRT Read Remote Temperature
02h 0000 0000 0 RS Read Status
03h 0000 0000 0 RC Read Configuration
04h 0000 0000 0 RMID Manufacturers ID
05h 0111 1111 127 RLCS Read Local T_CRIT Setpoint
07h 0111 1111 127 RRCS Read Remote T_CRIT
Setpoint
09h 0000 0000 0 WC Write Configuration
0Bh 0111 1111 127 WLCS Write Local T_CRIT Setpoint
0Dh 0111 1111 127 WRCS Write Remote T_CRIT
Setpoint
1.8.2 LOCAL and REMOTE TEMPERATURE REGISTERS
(Read Only Address 00h and 01h):
D7 D6 D5 D4 D3 D2 D1 D0
MSB Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB
D7–D0: Temperature Data. One LSB = 1˚C. Two’s complement format.
1.8.3 STATUS REGISTER
(Read Only Address 02h):
D7 D6 D5 D4 D3 D2 D1 D0
0 LTCRIT 0 RTCRIT 0 OPEN 0 0
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
(Read Address 03h /Write Address 09h):
D7 D6 D5 D4 D3 D2 D1 D0
T_CRIT_A
mask
0 0 0 0 0 0 0
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.
LM84
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