Really strange that your settings are 0 in overdrive.0 (which means regular
speed) after startup...?!?

Nice to hear that the CRC errors changed... That really looks like some
cable or signal problem which
should be possible to tune away with the slewrate.

# ipkg upgrade
Upgrading    owfs on root from 2.6p5-14 to 2.6p5-15...
Downloading
http://owfs.sourceforge.net/nslu2/packages/./owfs_2.6p5-15_armeb.ipk
Upgrading    owlib on root from 2.6p5-14 to 2.6p5-15...
Downloading
http://owfs.sourceforge.net/nslu2/packages/./owlib_2.6p5-15_armeb.ipk
Configuring owfs
Configuring owlib
# run-owfs
Using /lib/modules/2.4.22-xfs/kernel/fs/fuse/fuse.o
# cat /tmp/1wire/bus.0/system/adapter/overdrive.0
           1# 

Note that it's set to 1 (flexible speed) for me.... and I don't understand
how it could be changed just after startup.

# bash      
bash-3.2# ls -l /tmp/1wire/uncached/
drwxrwxrwx    1 root     root            8 Jul  4 23:40 10.94C7ED000800
drwxrwxrwx    1 root     root            8 Jul  4 23:40 37.11A401000000
drwxrwxrwx    1 root     root            8 Jul  4 23:40 81.465723000000
drwxr-xr-x    1 root     root            8 Jul  4 23:39 alarm
drwxr-xr-x    1 root     root            8 Jul  4 23:39 bus.0
drwxrwxrwx    1 root     root            8 Jul  4 23:40 simultaneous
bash-3.2# echo 2 > /tmp/1wire/bus.0/system/adapter/overdrive.0 
bash-3.2# ls -l /tmp/1wire/uncached/                           
drwxrwxrwx    1 root     root            8 Jul  4 23:40 37.11A401000000
drwxrwxrwx    1 root     root            8 Jul  4 23:40 81.465723000000
drwxr-xr-x    1 root     root            8 Jul  4 23:39 bus.0

(the ds1920 disappears since it doesn't support overdrive)

bash-3.2# echo 1 > /tmp/1wire/bus.0/system/adapter/overdrive.0 
bash-3.2# ls -l /tmp/1wire/uncached/                           
drwxrwxrwx    1 root     root            8 Jul  4 23:40 10.94C7ED000800
drwxrwxrwx    1 root     root            8 Jul  4 23:40 37.11A401000000
drwxrwxrwx    1 root     root            8 Jul  4 23:40 81.465723000000
drwxr-xr-x    1 root     root            8 Jul  4 23:39 alarm
drwxr-xr-x    1 root     root            8 Jul  4 23:39 bus.0
drwxrwxrwx    1 root     root            8 Jul  4 23:40 simultaneous
bash-3.2#

(the ds1920 is back in flexible speed)

bash-3.2# cat  /tmp/1wire/bus.0/system/adapter/pulldownslewrate.0       
           5
In this case slewrate is 5 (which is 0.83V/us). Read in
owlib/src/c/ow_ds9490.c for more info.

Starting owserver without --altUSB option is the same as setting:
bash-3.2# echo 1 > /tmp/1wire/bus.0/system/adapter/overdrive.0
bash-3.2# echo 5 > /tmp/1wire/bus.0/system/adapter/pulldownslewrate.0       
bash-3.2# echo 4 > /tmp/1wire/bus.0/system/adapter/writeonelowtime.0       
bash-3.2# echo 4 > /tmp/1wire/bus.0/system/adapter/datasampleoffset.0       

Starting owserver WITH --altUSB option is the same as setting:
bash-3.2# echo 1 > /tmp/1wire/bus.0/system/adapter/overdrive.0
bash-3.2# echo 3 > /tmp/1wire/bus.0/system/adapter/pulldownslewrate.0       
bash-3.2# echo 2 > /tmp/1wire/bus.0/system/adapter/writeonelowtime.0       
bash-3.2# echo 5 > /tmp/1wire/bus.0/system/adapter/datasampleoffset.0
(This setting have been reported to work for some AAG user before)       


/Christian


> Christian,
> after the installation of 2.65-15 version of owfs, i checked the value
> of
> /tmp/1wire/bus.0/system/adapter/overdrive.0 and i found a 0 (zero)
> there.
> Reading your posting i understand that, to be able to change the slew
> param, i
> must put a 1 on the overdrive.0 parameter.
> I issued a echo 1 > /tmp/1wire/bus.0/system/adapter/overdrive.0 and
> then i start
> tweeking the /tmp/1wire/bus.0/system/adapter/pulldownslewrate.0
> parameter
> ranging from 0 up to 7.
> The problem is still there but the errors are changed .
> The output of grep -v " 0" /tmp/1wire/bus.0/statistics/errors/* is now
> :
> 
> /tmp/1wire/bus.0/statistics/errors/BUS_select_low_errors:          24
> /tmp/1wire/bus.0/statistics/errors/CRC8_tries:           5
> 
> Actually i am tweeking even the other parameter you indicated in a
> previous
> posting : writeonelowtime.0 and datasampleoffset.0, i don't see any
> difference
> on the behaviour of the NSLU2.
> 
> I don't know if it make sense, i made the same test with
> /tmp/1wire/bus.0/system/adapter/overdrive.0 set to 0 and 2 with the
> same results
> as before.
> 
> Just a little remark: as said before , my network is composed by just
> two
> devices, the Bus master and the 2408 board. The twos are connected via
> a short
> (no more than 30 cm) rj45 cable.
> Regards
> Giuliano



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