
笔记本风扇控制方案.docx
2页3pin/4pin风扇接法连接线颜色风扇3pin接头风扇4pin街头里 八、、接地接地红(绿)+ 12V/+5V 供电+ 12V黄风扇转速侦测风扇转速侦测蓝无PWM3pin风扇的控制,通过将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RPMRound/1 minRound/secu sec/ RoundCounter value for 1PPR FAN60006000100(6000/60 sec)10000333(10000/30)5000500083.33(5000/60)12000400(12000/30)4000400066.667(4000/60)15000500(15000/30)3000300050(3000/60)20000666(20000/30)2000200033.333(2000/60)300001000(30000/30)1000100016.667(1000/60)600002000(40000/30)5005008.3(500/60)1200004000(120000/30)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 CPU 或 GPU 温度达到 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 。
