TC654 Microchip Technology, TC654 Datasheet - Page 18

• Manufacturer Part Number: TC654
• Description: (TC654 / TC655) PWM Fan Speed Controllers With Fan Fault Detection
• Manufacturer: Microchip Technology

TC654/TC655
6.2
The Fan Fault Threshold Registers (FAN_FAULT1 and
FAN_ FAULT2) are used to set the fan fault threshold
levels for fan 1 and fan 2, respectively. The Fan Fault
Registers are 8-bit, read/writable registers that allow
the fan fault RPM threshold to be set in 50 RPM incre-
ments. The default setting for both Fan Fault registers
is 500 RPM (0000 1010). The maximum set point
value is 12750 RPM. If the measured fan RPM (stored
REGISTER 6-2:
DS21734A-page 18
D(7)
0
0
0
1
1
.
.
FAN_FAULT1 & FAN_FAULT2
Threshold Registers
(FAN_FAULT1 & FAN_ FAULT2)
D(6)
0
0
0
1
1
.
.
FAN FAULT THRESHOLD REGISTERS (FAN_FAULT1 & FAN_FAULT2)
D(5)
0
0
0
1
1
.
.
D(4)
0
0
0
1
1
.
.
D(3)
0
0
0
1
1
.
.
in RPM1 and RPM2 Registers) drops below the value
that is set in the Fan Fault Registers for more than
2.4sec, a fan fault indication will be given. F1F (bit
0<0>) and F2F (bit 1<0>) in the Status Register indi-
cate fan fault conditions for fan 1 and fan 2, respec-
tively. The FAULT output will also be pulled low in a fan
fault condition. Changing FFCLR (bit 7<0>) in the Con-
figuration Register will reset the fan fault bits in the Sta-
tus Register as well as the FAULT output. See
Register 6-2 for the Fan Fault Threshold Register 8-bit
format.
D(2)
0
0
0
1
1
.
.
D(1)
0
0
1
1
1
.
.
2002 Microchip Technology Inc.
D(0)
0
0
0
0
1
.
.
12700
12750
RPM
100
50
0