Bump up fan frequency to 19kHz on EMC2103#1606
Bump up fan frequency to 19kHz on EMC2103#1606raivisr wants to merge 1 commit intobitaxeorg:masterfrom
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On second thought, it is probably even better to set the value to 0x00, or 26kHz. Intel 4 pin fan spec calls for 25Khz PWM frequency, with values 21-28kHz being acceptable. |
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A problem that this might face is that we don't know if all fans will work with such a high pwm signal. Manufacturers use all sorts of fans so it's impossible for us to figure out an ideal frequency. But this PR will be tested |
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Is it safe to assume that most if not all manufacturers make their fans to Intel spec? Also, we tested everything that we had at hand and all fans work just fine. Also, it is a PWM, a digital way to produce approximation of analog voltage, the higher the frequency, the closer the approximation. |
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Sounds fair, I'll give this a shot with 3 - 4 fan brands that I have laying around. |
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if that works for this fan controller, it is probably good idea to update all the others as well. might improve commanded vs observed fan speed tracking. |
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I was not able to reduce any high pitch noise. Can you elaborate a bit further on the brands of fan's you're using and at what fan speed you get a high pitch for reproducablity ? |
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Default EMC2103 PWM frequency is 2.441 kHz, some fans emit high pitched noise when driven with such low PWM frequency. This bumps up PWM frequency to 19.531 kHz, eliminates high pitched noise on those specific fans and should still work well with any other fan.