> > + This sets fan-divs to 2, among others.
> >
> > Where does it do that? Can't find it.
>
> That comment refers to the reset i.e. write 0x80 into register 0x00.
Oh, OK, I missed that at first.
> > The datasheet actually says that fan_div3 can be set to either 2 or
> > 8. It's controled by bit 6 of register 0x0b. It differs from the
> > other two divisors in that it is coded on a single bit while the
> > others have three, which let them chose between 8 different divisors
> > from 1 to 128. You could as well consider that the bit 6 of register
> > 0x0b controls the*second* bit of fan_div3, which MSB and LSB are
> > fixed to 0 and 1, respectively. This make div3 look more like div1
> > and 2 (to me at least, and should help in the code too).
>
> Where did you get this info from? In the "IT8705F Preliminary
> Environment Controller (EC) Programming Guide V0.3"
> (it8705f_PG_ec_v03.pdf) I can't find it. There the bits 7 and 6 of
> register 0x0b are only descripted as reserved. I downloaded above
> pdf-file directly from ITE Inc's web side!
The version I have says:
7 - Reserved
6 R/W FAN_TAC3 Counter Divisor
0: divided by 2
1: divided by 8
I don't remember where I got it from, although I'm pretty sure I also
got them from ITE's website. I don't remember the original name either
(I'm renaming files to a standardized format). Maybe the filesize will
help:
1644525 Jul 18 2000 IT8702-0.3.pdf
1281351 Mar 16 2001 IT8705F-p1-0.3.pdf <-- this one
657518 Mar 16 2001 IT8705F-p2-0.3.pdf
1150423 Mar 25 2002 IT8712F-0.6.pdf
993541 Jun 11 09:20 IT8712F-0.7.pdf
I may send any of them to you if you want.
> > (BTW, does this really compile? I thought you couldn't declare a
> > variable after real code in a given block.)
>
> Umm..., I'm a C++ guy :-) and in C++ it is perfectly OK to declare a
> variable anywhere inside a block. It compiles perfectly with gcc 3.3.1
> on my SuSE 8.2 box, anyway.
Still I don't want this in our repository.
> > You don't need a special case for 1, unless I'm missing something.
> > And you definitely want to return 1 as the default value, as it was
> > the case before, because fan_div = 2 is a reasonable default. I also
> > believe that we should try to find out the nearest divisor from what
> > the user entered. Setting the divisor to 128, or either 2 , when the
> > user asked for 31, is poor. We can do better than that. What about
> > that:
> >
> > extern inline u8 DIV_TO_REG(long val)
> > {
> > u8 i;
> > for( i = 0; i < 7; i++ )
> > if( val>>i == 1 )
> > return i;
> > return 2;
> > }
> >
> > This considers the highest weighted bit, whatever the lower bits are
> > set to.
>
> OK, but it your code returns the register value for a divisor of four
> (4) in case the desired value is greater than 32 (=1<<6), it should be
> a seven for a divisor of 128.
> [...]
> return 7;
> }
We're both wrong here. I am because what I wanted is return 1 (for a fan
divisor of 2, as said above). You are because 1<<6 is 64, not 32 ;) And
I am once again because the condition is "i <= 7", not "i < 7". So this
should read:
extern inline u8 DIV_TO_REG(long val)
{
u8 i;
for( i = 0; i <= 7; i++ )
if( val>>i == 1 )
return i;
return 1;
}
Is it OK now?
> > I want the chip reset (0x80 at 0x00) gone, and everything else that
> > causes trouble with it. The rest will be kept, inside an init=1
> > conditional. Is it OK?
>
> It's fine with me, thought I felt better keeping the chip reset in,
> too. Inside a if(reset==1) with reset defaulting to 0.
OK for me.
Thanks.
--
Jean Delvare
http://www.ensicaen.ismra.fr/~delvare/
