Multichannel remote/local temperature sensors – Rainbow Electronics MAX1989 User Manual
Page 12
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level sensitive). Successful reading of the alert
response address clears the interrupt latch.
Command Byte Functions
The 8-bit command byte register (Table 4) is the master
index that points to the various other registers within the
MAX1668/MAX1805/MAX1989. The register’s POR
state is 0000 0000, so that a receive byte transmission
(a protocol that lacks the command byte) that occurs
immediately after POR returns the current local temper-
ature data.
MAX1668/MAX1805/MAX1989
†
Multichannel Remote/Local
Temperature Sensors
12
______________________________________________________________________________________
Table 4. Command Byte Bit Assignments for MAX1668/MAX1805/MAX1989
*If the device is in hardware standby mode at POR, all temperature registers read 0°C.
**Not available for MAX1805.
REGISTER
COMMAND
POR STATE
FUNCTION
RIT
00h
0000 0000*
Read local temperature
RET1
01h
0000 0000*
Read remote DX1 temperature
RET2
02h
0000 0000*
Read remote DX2 temperature
RET3**
03h
0000 0000*
Read remote DX3 temperature
RET4**
04h
0000 0000*
Read remote DX4 temperature
RS1
05h
0000 0000
Read status byte 1
RS2
06h
0000 0000
Read status byte 2
RC
07h
0000 0000
Read Configuration Byte
RIHL
08h
0111 1111
Read local T
HIGH
limit
RILL
09h
1100 1001
Read local T
LOW
limit
REHL1
0Ah
0111 1111
(0110 1110)
Read remote DX1 T
HIGH
limit (MAX1989)
RELL1
0Bh
1100 1001
Read remote DX1 T
LOW
limit
REHL2
0Ch
0111 1111
Read remote DX2 T
HIGH
limit
RELL2
0Dh
1100 1001
Read remote DX2 T
LOW
limit
REHL3**
0Eh
0111 1111
Read remote DX3 T
HIGH
limit
RELL3**
0Fh
1100 1001
Read remote DX3 T
LOW
limit
REHL4**
10h
0111 1111
Read remote DX4 T
HIGH
limit
RELL4**
11h
1100 1001
Read remote DX4 T
LOW
limit
WC
12h
N/A
Write configuration byte
WIHL
13h
N/A
Write local T
HIGH
limit
WILL
14h
N/A
Write local T
LOW
limit
WEHI1
15h
N/A
Write remote DX1 T
HIGH
limit
WELL1
16h
N/A
Write remote DX1 T
LOW
limit
WEHI2
17h
N/A
Write remote DX2 T
HIGH
limit
WELL2
18h
N/A
Write remote DX2 T
LOW
limit
WEHI3**
19h
N/A
Write remote DX3 T
HIGH
limit
WELL3**
1Ah
N/A
Write remote DX3 T
LOW
limit
WEHI4**
1Bh
N/A
Write remote DX4 T
HIGH
limit
WELL4**
1Ch
N/A
Write remote DX4 T
LOW
limit
MFG ID
FEh
0100 1101
Read manufacture ID
DEV ID
FFh
0000 0011 (0000 0101)
[0000 1011]
Read device ID (for MAX1805) [for MAX1989]