k8v-x and asus probe question

In article <Uslrd.14314$hp3.2131437@read2.cgocable.net>, "Jeremy & Kandie
Michea" <hickorysticks.RemoveThis@cogeco.ca> wrote:

 > Hi. I recently bought a k8v-X motherboard and have Asus PC probe installed.
 > I went through some of the settings and noticed "chassis fan" and "power
 > fan" as reading at zero values. Now I don't have a chassis fan so that makes
 > sense but I have PSU fan, of course, and its reading at zero makes no sense.
 > I went into the BIOS and the hardware monitor section and there is no
 > listing there for PSU fan RPM's, just chassis and cpu.
 >
 > Could not having a PSU fan listing in the bios cause this zero in Asus PC
 > probe? There is nothing in the BIOS to report so Asus probe just gives a
 > zero? The fan seems to run fine by the way, I feel the air coming from the
 > back of the pc with my hand.
 >
 > Any help or advice appreciated.
 > Thanks

Fan monitors seem to have a common method for their implementation.
They use an internal clock, and they measure the interval between
pulses from the fan tacho input, with that clock. The internal clock
used, is scalable with a power_of_two divisor, which is set to 2
by default (and doesn't appear to be user selectable). Some chips
only have an eight bit register, to accumulate the counts.

As the fan speeds run slower and slower, the number of counts collected
in the eight bit register grows and grows. When the register reaches
255, it runs out of room, and that full count defines the _lowest_
speed of the fan that can be measured. Now, I don't see an overflow bit
in the interface, but the software must have some way of knowing the
register overflowed. To the software, there is no difference between
a slight overflow (when the fan is running just a little slower
than the circuit can measure), or the fan has stopped rotating (locked
rotor), as when the fan is dead, the register will also overflow.
As a result, when overflow is detected, it is treated as
zero RPM, because that is the most pessimistic interpretation of
the counter overflow condition.

The problem could be easily solved by changing the internal clock
divisor, so a slower clock is used to measure the interval between
fan pulses. But, until some hacker finds a way to do this, you
are stuck with whatever limit is in the Asus software.

Note - The datasheets I've read, don't explain all this in so many
words, so this is my interpretation of what I'm seeing in the way
of register definitions.

HTH,
Paul<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: k8v-x and asus probe question 

Jeremy & Kandie Michea wrote:
 > Hi. I recently bought a k8v-X motherboard and have Asus PC probe installed.
 > I went through some of the settings and noticed "chassis fan" and "power
 > fan" as reading at zero values. Now I don't have a chassis fan so that makes
 > sense but I have PSU fan, of course, and its reading at zero makes no sense.
 > I went into the BIOS and the hardware monitor section and there is no
 > listing there for PSU fan RPM's, just chassis and cpu.
 >
 > Could not having a PSU fan listing in the bios cause this zero in Asus PC
 > probe? There is nothing in the BIOS to report so Asus probe just gives a
 > zero? The fan seems to run fine by the way, I feel the air coming from the
 > back of the pc with my hand.
 >
 > Any help or advice appreciated.
 > Thanks
 >
 >
 >

Is the power supply actually connected into the power supply fan header
on the motherboard? If it doesn't have such a connector on the power
supply, the motherboard can't read the fan RPM..

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr.RemoveThis@nospamshaw.ca
Home Page: <a style='text-decoration: underline;' href="http://www.roberthancock.com/" target="_blank">http://www.roberthancock.com/</a><!-- ~MESSAGE_AFTER~ -->
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