User guide

MAX6678
2-Channel Temperature Monitor with Dual Automatic
PWM Fan-Speed Controller and Five GPIOs
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Table 2. Register Map
READ/
WRITE
REGISTER
NO.
/ADDRESS
POR
STATE
FUNCTION D7 D6 D5 D4 D3 D2 D1 D0
R 00h 0000 0000
Temperature
channel 1
MSB
(+128°C)
——————
LSB
(+1°C)
R 01h 0000 0000
Temperature
channel 2
MSB
(+128°C)
——————
LSB
(+1°C)
R/W 02h 0001 1000
Configuration
byte
Reserved;
set to 0
Res er ved ;
s et t o 0
Timeout:
0 =
enabled,
1 =
disabled
PWMOUT
1 PWM
invert
PWMOUT
2 PWM
invert
Min duty
cycle: 0
= 0%,
1 = fan -
start duty
cycle
Temp
channel 2
source: 1
= local, 0
= remote
2
Spin-up
disable
R/W 03h 0110 1110
Temperature
channel 1 OT
limit
MSB — — — ———
LSB
(+1°C)
R/W 04h 0101 0000
Temperature
channel 2 OT
limit
MSB — — — ———
LSB
(+1°C)
R 05h 00xx xxxx OT status
Channel
1: 1 =
fault
Channel
2: 1 =
fault
——————
R/W 06h 00xx xxxx OT mask
Channel
1: 1 =
masked
Channel
2: 1 =
masked
——————
R/W 07h
0110 000x
(96 = 40%)
PWMOUT1 start
duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R/W 08h
0110 000x
(96 = 40%)
PWMOUT2 start
duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R/W 09h
1111 000x
(240 = 100%)
PWMOUT1 max
duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R/W 0Ah
1111 000x
(240 = 100%)
PWMOUT2 max
duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R/W 0Bh 0000 000x
PWMOUT1
target duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R/W 0Ch 0000 000x
PWMOUT2
target duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
R 0Dh 0000 000x
PWMOUT1
instantaneous
duty cycle
MSB
(128/240)
—————
LSB
(2/240)
—
***GPIO0 through GPIO4 POR values set by Preset0 through Preset4.