SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 261

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Datasheet
SMSC SCH311X
24.2.17.1
24.2.17.2
Since (Zone 1 Low Temp Limit) + (Zone 1 Range) = 50 ° C + 8 ° C = 58 ° C, the fan controlled by PWM1
will run at 100% duty cycle when the temperature of the Zone 1 sensor is at 58 ° C.
Since the midpoint of the fan control range is 54 ° C, and the median duty cycle is 75% (Halfway
between the PWM Minimum and 100%), PWM1 duty cycle would be 75% at 54 ° C.
Above (Zone 1 Low Temp Limit) + (Zone 1 Range), the duty cycle must be 100%.
The PWM frequency bits [3:0] determine the PWM frequency for the fan. If the high frequency option
is selected the associated FANTACH inputs must be configured for Mode 1.
PWM Frequency Selection (Default =1011 bits=25kHz)
Range Selection (Default =1100=32 ° C)
SELECT BITS[3:0]
FREQUENCY
RAN[3:0]
0000
0001
0010
0100
0101
1000
1001
1010
0000
0001
0010
0100
0101
0011
0110
0111
1011
1100
1101
1110
0011
0110
1111
Table 24.10 Register Setting vs. Temperature Range
Table 24.9 PWM Frequency Selection
DATASHEET
245
14.318MHZ CLOCK SOURCE
25kHz (default)
FREQUENCY
RANGE ( ° C)
Reserved
Reserved
Reserved
Reserved
11.0 Hz
14.6 Hz
21.9 Hz
29.3 Hz
35.2 Hz
44.0 Hz
58.6 Hz
87.7 Hz
15kHz
20kHz
30kHz
3.33
6.67
2.5
2
4
5
8
Rev 0.2 (09-28-04)