[lm-sensors] Jetway J7F2 with f71805: PWM not working

[lm-sensors] Jetway J7F2 with f71805: PWM not working

[Phil Endecott]

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Dear All,

I have a Jetway J7F2 motherboard; it's a mini-ITX board with a VIA C7 
processor and the Fintec f71805f sensor chip.

Temperature and fan speed measurements work correctly, and most of the 
voltages look right to me.  I have no idea whether the values for 
Vtt1.2V, Vram, Vchip and Vcc1.5V are right:

# sensors
f71805f-isa-0290
Adapter: ISA adapter
+3.3V:     +3.42 V  (min =  +3.01 V, max =  +3.58 V)
Vtt1.2V:   +0.86 V  (min =  +0.00 V, max =  +2.02 V)
Vram:      +1.46 V  (min =  +0.00 V, max =  +4.03 V)
Vchip:     +3.58 V  (min =  +0.00 V, max =  +6.31 V)
+5V:       +5.13 V  (min =  +0.00 V, max = +10.59 V)
+12V:     +12.32 V  (min =  +0.00 V, max = +22.18 V)
Vcc1.5V:   +1.11 V  (min =  +0.00 V, max =  +2.02 V)
Vcore:     +1.09 V  (min =  +0.00 V, max =  +2.02 V)
5VSB:      +5.13 V  (min =  +0.00 V, max = +10.59 V)
CPU Fan:     0 RPM  (min =    0 RPM)
Sys Fan:     0 RPM  (min =    0 RPM)
Aux Fan:  4559 RPM  (min =    0 RPM)
CPU Temp:    +22������C  (high =   +70������C, hyst =   +69������C)         [diode]
Sys Temp:    +31������C  (high =  +255������C, hyst =    +0������C)         [diode]
Aux Temp:   +115������C  (high =  +255������C, hyst =    +0������C)         [thermistor]

(err, well some of those numbers look a bit odd but that's just because 
I have been messing around.)

Unfortunately, PWM fan speed control doesn't seem to work.  I can write 
things to the pwm /sys devices, but nothing happens.  For example, I 
have asked for them all to be off:

localhost:/sys/devices/platform/f71805f.656# for i in pwm*; do echo -n 
$i ': '; cat $i; done
pwm1 : 0
pwm1_enable : 1
pwm1_freq : 187500
pwm1_mode : 1
pwm2 : 0
pwm2_enable : 1
pwm2_freq : 187500
pwm2_mode : 1
pwm3 : 0
pwm3_enable : 1
pwm3_freq : 187500
pwm3_mode : 1

(I hope I have understood this correctly; 'enable=1' means manual 
control, and 'pwm=0' means off, right?)

But I still see 12V on all of the fan connectors and they run at full speed.

So the possibilities are:
- I'm doing something wrong (very likely, I'm new to this).
- The lm-sensors code is doing something wrong.
- My board doesn't actually have PWM control on these outputs and 
they're hard-wired to 12V.

Right now I think that the last of those is quite likely; I can't 
exactly trace the 12V from the power input all the way to the fan 
connectors, but I can see where it goes for much of the distance and I 
don't see any power transistors.

So, has anyone else had any experience with this board?  Has PWM been 
known to work with other boards with this chip?  Is it common for fan 
connectors to not have PWM control?

Finally, somewhat O.T., if it seems that I can't control the fan speed 
on this board, can anyone suggest a "hardware hack"?  In the past I 
have built fan speed controllers with thermisters and op-amps, but 
something with software control would be better.


Many thanks in advance for any suggestions.


Phil.






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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Juerg Haefliger]

Hi Phil,

On 6/2/07, Phil Endecott <spam_from_lm_sensors@chezphil.org> wrote:
> Dear All,
>
> I have a Jetway J7F2 motherboard; it's a mini-ITX board with a VIA C7
> processor and the Fintec f71805f sensor chip.
>
> Temperature and fan speed measurements work correctly, and most of the
> voltages look right to me.  I have no idea whether the values for
> Vtt1.2V, Vram, Vchip and Vcc1.5V are right:
>
> # sensors
> f71805f-isa-0290
> Adapter: ISA adapter
> +3.3V:     +3.42 V  (min =  +3.01 V, max =  +3.58 V)
> Vtt1.2V:   +0.86 V  (min =  +0.00 V, max =  +2.02 V)
> Vram:      +1.46 V  (min =  +0.00 V, max =  +4.03 V)
> Vchip:     +3.58 V  (min =  +0.00 V, max =  +6.31 V)
> +5V:       +5.13 V  (min =  +0.00 V, max = +10.59 V)
> +12V:     +12.32 V  (min =  +0.00 V, max = +22.18 V)
> Vcc1.5V:   +1.11 V  (min =  +0.00 V, max =  +2.02 V)
> Vcore:     +1.09 V  (min =  +0.00 V, max =  +2.02 V)
> 5VSB:      +5.13 V  (min =  +0.00 V, max = +10.59 V)
> CPU Fan:     0 RPM  (min =    0 RPM)
> Sys Fan:     0 RPM  (min =    0 RPM)
> Aux Fan:  4559 RPM  (min =    0 RPM)
> CPU Temp:    +22°C  (high =   +70°C, hyst =   +69°C)         [diode]
> Sys Temp:    +31°C  (high =  +255°C, hyst =    +0°C)         [diode]
> Aux Temp:   +115°C  (high =  +255°C, hyst =    +0°C)         [thermistor]
>
> (err, well some of those numbers look a bit odd but that's just because
> I have been messing around.)
>
> Unfortunately, PWM fan speed control doesn't seem to work.  I can write
> things to the pwm /sys devices, but nothing happens.  For example, I
> have asked for them all to be off:
>
> localhost:/sys/devices/platform/f71805f.656# for i in pwm*; do echo -n
> $i ': '; cat $i; done
> pwm1 : 0
> pwm1_enable : 1
> pwm1_freq : 187500
> pwm1_mode : 1
> pwm2 : 0
> pwm2_enable : 1
> pwm2_freq : 187500
> pwm2_mode : 1
> pwm3 : 0
> pwm3_enable : 1
> pwm3_freq : 187500
> pwm3_mode : 1
>
> (I hope I have understood this correctly; 'enable=1' means manual
> control, and 'pwm=0' means off, right?)
>
> But I still see 12V on all of the fan connectors and they run at full speed.
>
> So the possibilities are:
> - I'm doing something wrong (very likely, I'm new to this).
> - The lm-sensors code is doing something wrong.
> - My board doesn't actually have PWM control on these outputs and
> they're hard-wired to 12V.
>
> Right now I think that the last of those is quite likely; I can't
> exactly trace the 12V from the power input all the way to the fan
> connectors, but I can see where it goes for much of the distance and I
> don't see any power transistors.

If you have an Ohmmeter, you can measure the resistance between the
fan connector pins and 12V & ground. If both readings are 0 you're out
of luck, i.e., the fan is hardwired to 12V/ground.


> So, has anyone else had any experience with this board?  Has PWM been
> known to work with other boards with this chip?  Is it common for fan
> connectors to not have PWM control?

I can't speak for your board but the same applies to my EPIA M10000.
No PWM control, stupid design.


> Finally, somewhat O.T., if it seems that I can't control the fan speed
> on this board, can anyone suggest a "hardware hack"?  In the past I
> have built fan speed controllers with thermisters and op-amps, but
> something with software control would be better.

That's fairly simple, typically a transistor between the fan and
ground, controlled by the PWM controller. The hard part is to get to
the components, especially on a Mini ITX board. You might have to
solder wires to pins and lift pins and fun stuff like that.
Alternatively, you could use a i2c PWM controller (that is of course
supported by lm-sensors) and hook it up to the boards I2C bus, Mini
ITX typically have it exposed on a header.
Google it.

...juerg


>
> Many thanks in advance for any suggestions.
>
>
> Phil.
>
>
>
>
>
>
> _______________________________________________
> lm-sensors mailing list
> lm-sensors@lm-sensors.org
> http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
>

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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Phil Endecott]

Thanks for the quick reply.

Juerg Haefliger wrote:
> On 6/2/07, Phil Endecott <spam_from_lm_sensors@chezphil.org> wrote:
>> Finally, somewhat O.T., if it seems that I can't control the fan speed
>> on this board, can anyone suggest a "hardware hack"?  In the past I
>> have built fan speed controllers with thermisters and op-amps, but
>> something with software control would be better.
>
> That's fairly simple, typically a transistor between the fan and
> ground, controlled by the PWM controller. The hard part is to get to
> the components, especially on a Mini ITX board. You might have to
> solder wires to pins and lift pins and fun stuff like that.

Well this Fintek chip doesn't look too impossible; 1.27 mm pitch I guess.

The docs say that Fintek provided a datasheet; does someone have a copy 
of it that they could send me?  Or just let me know the pin numbers for 
the PWM outputs, and what sort of outputs they are?

> Alternatively, you could use a i2c PWM controller (that is of course
> supported by lm-sensors) and hook it up to the boards I2C bus, Mini
> ITX typically have it exposed on a header.

Yes, good idea, I'll investigate.  I don't suppose anyone knows of a 
ready-made module or anything like that?


Phil.





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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Phil Endecott]

A moment ago I wrote:
> The docs say that Fintek provided a datasheet; does someone have a copy of it that they could 
> send me? Or just let me know the pin numbers for the PWM outputs, and what sort of outputs they 
> are?

Don't worry, it's on their website: http://www.fintek.com.tw/files/productfiles/F71805F_V025.pdf


Phil.





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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Jean Delvare]

Hi Phil,

On Sat, 02 Jun 2007 20:48:46 +0100, Phil Endecott wrote:
> localhost:/sys/devices/platform/f71805f.656# for i in pwm*; do echo -n 
> $i ': '; cat $i; done
> pwm1 : 0
> pwm1_enable : 1
> pwm1_freq : 187500
> pwm1_mode : 1
> pwm2 : 0
> pwm2_enable : 1
> pwm2_freq : 187500
> pwm2_mode : 1
> pwm3 : 0
> pwm3_enable : 1
> pwm3_freq : 187500
> pwm3_mode : 1
> 
> (I hope I have understood this correctly; 'enable=1' means manual 
> control, and 'pwm=0' means off, right?)

Yes.

> So, has anyone else had any experience with this board?  Has PWM been 
> known to work with other boards with this chip?  Is it common for fan 
> connectors to not have PWM control?

I have a Jetway K8M8MS motherboard with a Fintek F71805F chip, where
pwm1 controls fan1. So I am reasonably certain that fan speed control is
properly implemented by my f71805f driver. However, you are not the
first one to report about being enable to control the fans using this
driver. It seems to be common that motherboard manufacturers don't
bother wiring things properly :(

-- 
Jean Delvare

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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Phil Endecott]

Jean Delvare wrote:
> On Sat, 02 Jun 2007 20:48:46 +0100, Phil Endecott wrote:
>> So, has anyone else had any experience with this board?  Has PWM been 
>> known to work with other boards with this chip?  Is it common for fan 
>> connectors to not have PWM control?
>
> I have a Jetway K8M8MS motherboard with a Fintek F71805F chip, where
> pwm1 controls fan1. So I am reasonably certain that fan speed control is
> properly implemented by my f71805f driver. However, you are not the
> first one to report about being enable to control the fans using this
> driver. It seems to be common that motherboard manufacturers don't
> bother wiring things properly :(

Thanks Jean.  I have scoped the three outputs and they all seem to be 
outputting the expected PWM waveforms.  Curiously, the PWM1 pin has a 
track that goes somewhere; it's not a fan (unless I have screwed up) so 
what could it be?  I'm a bit concerned that it is used for something 
else that I'm going to break...

Anyway I have constructed a driver circuit based on the example from 
the datasheet and will be trying it out soon.  The most difficult part 
was attaching a wire to the pin; despite a reasonably fine soldering 
iron and a magnifying glass I still managed to bridge it to its 
neighbours.  I have glued the wire down to the board as strain-relief 
for my soldering, and will try it out once the glue is dry.

Regards,

Phil.





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Re: [lm-sensors] Jetway J7F2 with f71805: PWM not working

[Phil Endecott]

Dear All,

My home-made fan driver circuit seems to be working.  Let me know if 
you are interested and I will describe the circuit; it's just an NMOS 
FET and a PNP transistor, as suggested in the Fintek datasheet.

However, the fan tacho input is not correctly measured at low PWM 
values / voltages / speeds.  I believe that this is because the signal 
on the wire from the fan switches between ground and the fan supply 
[*].  The motherboard must have a resistor divider to get the 12V on 
this wire down to the safe input for the chip (again there is a circuit 
for this in the datasheet).  But if the (average??) fan supply voltage 
is too low, the input to the chip sees 0.  Or, the tacho signal is 
modulated by the PWM signal.

I presume that this is a standard problem.  Do other motherboards that 
have PWM fan control have unreliable tachos at low speed, or do they 
have extra components between the fan's tacho wire and the chip to deal 
with this?  Maybe it depends on the PWM frequency?

Google finds an Analogue Devices chip 
(http://www.analog.com/library/analogdialogue/archives/38-02/fan_speed.html) 
where they describe this problem, and suggest that when you want to 
take a tacho reading you should briefly set the PWM output to 100%.  
Presumably this would have to be done within the chip for the 
tacho-tracking automatic mode to work, though it could also be 
implemented by the O.S. for other control mechanisms.

[*] Why they have done it like that I cannot imagine.  It would have 
been much simpler to have the switch in the fan go from ground to 
open-circuit, and to have whatever pullup resistor to whatever voltage 
you need on the motherboard.....


Regards,

Phil.





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