W83627HF Datasheet, PDF (116/185 Pages) Winbond – WINBOND I/O

W83627HF/F
PRELIMINARY
11.4.2 Fan speed control
The W83627HF provides 2 sets for fan PWM speed control. The duty cycle of PWM can be
programmed by a 8-bit registers which are defined in the Bank0 CR5A and CR5B. The default duty
cycle is set to 100%, that is, the default 8-bit registers is set to FFh. The expression of duty can be
represented as follows.
Duty − cycle(%) = ^{Programmed 8 - bit Register Value} × 100%
255
The PWM clock frequency also can be program and defined in the Bank0.CR5C . The application
circuit is shown as follows.
+12V
R1
R2
PWM Clock Input
D
G
NMOS
S
PNP Transistor
+
C
FAN
-
Figure 11.5
11.5 SMI# interrupt mode
11.5.1 Voltage SMI# mode :
SMI# interrupt for voltage is Two-Times Interrupt Mode. Voltage exceeding high limit or going
below low limit will causes an interrupt if the previous interrupt has been reset by reading all the
interrupt Status Register. (Figure 11.6 )
11.5.2 Fan SMI# mode :
SMI# interrupt for fan is Two-Times Interrupt Mode. Fan count exceeding the limit, or exceeding
and then going below the limit, will causes an interrupt if the previous interrupt has been reset by
reading all the interrupt Status Register. (Figure 11.7 )
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Publication Release Date: Jul 1999
Revision 0.53