On Mon, 05 Dec 2011 17:34:15 +0530, Charles wrote: > On 04/12/11 16:30, lm-sensors-request@xxxxxxxxxxxxxx wrote: > > Date: Sun, 4 Dec 2011 11:03:45 +0100 > > From: Jean Delvare <khali@xxxxxxxxxxxx> > > > > Hi Charles, > [snip] > > On 4-pin headers, the PWM signal is separated from the power. So you > > can't control a 3-wire fan plugged in a 4-pin header (the PWM signal is > > on the unconnected pin [1].) > > > > -- Jean Delvare > > Hello Jean :) > > I already replied to this but just realised I am controlling a 3-wire > S-Flex SFF21E fan > (http://www.scythe-usa.com/product/acc/002/sflex_detail.html) on a > 4-wire port on an ASUS P8H76-V motherboard (works on both CHA_FAN and > CHA_FAN2). > > If the 4-pin fan header is regarded as a 3-pin header with an extra pin > then the unconnected pin is the extra pin. > > Perhaps ASUS have used an unconventional pinout ... ? This would be very unlikely, these pin mappings are highly standard, and any vendor deviating from this standard would expose themselves to the customer's wrath ;) The manual clearly documents the 4th (extra) pin as CPU FAN PWM, as expected. I can imagine that Asus came up with a way to detect whether the fan connector has 3 or 4 wires, and to route the PWM signal appropriately. I see no mention of this in the manual though. -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
