On Sun, 04 Jun 2006, Jean Delvare wrote: > Definitely not the LM75, as it is a temperature-only sensor chip. But I My bad, I should have typed lm85 (which would not be strictly correct, either: the ADM1027 does it. It is a LM85 compatible chip, but I don't think the lm85b/c can do it). > indeed. Strangely enough, some vendors are doing the opposite and > propose 4-wire fans, the idea being that tick counts tend to be lost > when fan speed control is in use on 3-wire fans. As soon as you drive fans using PWM you screw up any sort of simple tick counters completely, as you have a spike on every PWM cycle start, plus no spikes generated during the second phase of the PWM cycle. Probably they want four wires so that you can have Vcc, GND, Vcc-sense and sense, so that PWM does not disable the sensor. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
