User guide

MAX1669
Fan Controller and Remote Temperature Sensor
with SMBus Serial Interface
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REGISTER COMMAND FUNCTION
00h Reserved for future useN/A
RTEMP 01h Read latest temperatureN/A
RSTAT 02h Read status byte (temp flags, I/O_ states)N/A
RCFG 03h Read configuration byte0000 0010b
04h Reserved for future useN/A
05h Reserved for future useN/A
06h Reserved for future useN/A
RHI 07h Read T
HIGH
limit0111 1111b
RLOW 08h Read T
LOW
limit1100 1001b
WCFG 09h Write configuration byteN/A
0Ah Reserved for future useN/A
0Bh Reserved for future useN/A
0Ch Reserved for future useN/A
WHI 0Dh Write T
HIGH
limitN/A
WLOW 0Eh Write T
LOW
limitN/A
OSHT 0Fh
One-shot command. Will execute a single conversion even if the
device is in software standby.
N/A
RCRIT 10h Read T
CRIT
limit0110 0100b
RPROT 11h Read write-once protection byte0000 0000b
RFREQ 12h Read PWM frequency0000 0000b
RDUTY 13h Read FAN duty factor0000 0000b
RGPIO 14h Read GPIO data1100 0000b
15h Reserved for future useN/A
16h Reserved for future useN/A
17h Reserved for future useN/A
WCRIT
POR STATE
18h Write T
CRIT
limitN/A
WPROT 19h Write write-once protection byteN/A
WFREQ 1Ah Write PWM frequencyN/A
WDUTY 1Bh Write FAN duty factorN/A
WGPIO 1Ch Write GPIO dataN/A
RFU 1Dh-FDh Reserved for future useN/A
MFG ID FEh Manufacturing ID code = 4Dh, ASCII code for “M” (for Maxim)
Least Sig Byte
0100 1101b
DEV ID FFh Device ID code, specific to MAX1669
Least Sig Byte
0000 0101b
Table 3. Command Byte Bit Assignments
ID Codes