2024年3月25日发(作者：)

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一、3pin/4pin风扇接法

连接线颜色

黑

接地接地

风扇3pin接头风扇4pin街头

红（绿）

+12V/+5V 供电+12V

黄风扇转速侦测风扇转速侦测

PWM

蓝

3pin风扇的控制，通过将

无

EC出去的PWM转化出稳定的电压，

然后再送给风扇的正极，通过电压的高低来控制风扇的转速。

4pin风扇的控制，首先需要恒定的+12v电压，风扇的转速大小是

直接由PWM控制。

PWM的频率根据实际风扇及噪音的大小来设定。

二、风扇转速侦测表

RPM Round/1 min Round/sec u sec/ Round Counter value for

1PPR FAN

333(10000/30)

400(12000/30)

500(15000/30)

666(20000/30)

1000(30000/30)

2000(40000/30)

4000(120000/30)

6000

5000

4000

3000

2000

1000

500

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6000

5000

4000

3000

2000

1000

500

100(6000/60 sec) 10000

83.33(5000/60)

66.667(4000/60)

50(3000/60)

33.333(2000/60)

16.667(1000/60)

8.3(500/60)

12000

15000

20000

30000

60000

120000

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RPM (round / min) = 60,000,000 / (FANMON*30)

To enable the monitor function of fan feedback speed, the FANCFG bit_0

should be set. If fan speed is too slow to calculate, the fan timeout error flag

(FANSTS bit_1) will be set. The interrupt should be set when monitoring

update interrupt and timeout interrupt. The update flag is in FANSTS bit 0.

The Fan PWM is a 12-bit counter clocked by system clock with a resulting

4.096~0.256ms cycle time. If FANCFG bit_1 is set, the PWM is controlled

automatically by comparing the difference between FANMON (FAN monitor

speed) and FANSET (set FAN target speed). If FANMON is larger than

FANSET, it indicates the current fan speed is too slow, the PWM should

increase its duty cycle to increase the fan speed, and vice versa. The PWM will

remain still if (FANMON –FANSET) is less than four.

If FANCFG bit_1 is clear, the PWM is controlled manually by firmware.

Please note that the FANPWM value should be set by low-byte then

high-byte sequence

要打开风扇转速侦测功能，FANCFG_BIT 0 要置为1。

三、风扇损坏处理方案

根据本机种设定最低转速时的FANMON为判断点，

如果反馈回来的FANMON的值小于此判断点，同时

到风扇的最低停转点，

1，先至少降频5s。

2，如果条件仍然成立，就shutdown。

CPU或GPU温度达

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