w83627ehf Winbond Electronics Corp America, w83627ehf Datasheet - Page 36

• Manufacturer Part Number: w83627ehf
• Description: W83627ehf/ef W83627ehg/eg Winbond Lpc I/o
• Manufacturer: Winbond Electronics Corp America

W83627EHF/EF, W83627EHG/EG
6.4.2
Fan speed control
W83627EHF/EHG provides two controllable methods for Fan speed control. One is PWM duty cycle
output and the other is DC voltage output. Either PWM or DC output can be programmed at Bank0
Index 04h.bit1~0 , Index 12h.bit0 and Index 62h.bit6.
6.4.2.1. PWM Duty Cycle Output
The W83627EHF/EHG provides maximum 4 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 Index 01h, Index 03h, Index
11h and Index 61h. 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.
Programmed
- 8
bit
Register
Value
Dutycycle
(%)
u
100
%
255
The PWM clock frequency also can be program and defined in the Bank0 Index 00h, Index 02h, Index
10h and Index 60h.
6.4.2.2. DC Voltage Output
The W83627EHF/EHG has a 6 bit DAC which produces 0 to 3.3 volts DC output that provides
maximum 4 sets for fan speed control. The analog output can be programmed in the Bank0 Index 01h,
Index 03h, Index 11h and Index 61h. The default value is 111111YY,YY is reserved 2 bits, that is
default output value is nearly 3.3 V. The expression of output voltage can be represented as follow ,
Programmed
- 6
bit
Register
Value
3
VCC
u
`
Output Voltage (V)
64
-30-