Soren Kristensen wrote:
> Hi Everybody,
> 
> After investigating the problems with some CompactFlash cards we have 
> found out:

Soren,

Fist thanks for doing this.  Additional comments within.

> There are a number of CF cards that don't follow the ATA specs regarding 
> to RESET line behavior, more specific, they totally ignore the RESET 
> line....
> 
> There are two issues with that when using those CF cards in a net5501:
> 
> 1) The "set flash=primary|secondary" setting is done by setting the CSEL 
> (cable select) line to master or slave and then issue a reset. The CF 
> card are then supposed to reset and recognize the new CSEL setting.
> 
> CF cards that don't do that will just use the hardware default. In early 
> net5501 that was slave, we changed that to master so at least non 
> standard CF cards could be used in the most common way.

Was the change a hardware change or a firmware change?  Is there a known 
serial number when this change was made?  I have several net5501's 
ranging from the first production batch to units shipped in February.  A 
majority of these are using Transcend Industrial CF cards.  One 
recognizes the card as Primary Master.  The three more recent units all 
recognize the cards as Primary Slave.  Is there a chance that after a 
reboot, the net5501 would read a Primary Master as Primary Slave?  If so 
that's a huge potential issue for me.

> 2) Some boards have a problem with a short glitch on the DASP line. That 
> shouldn't normally matter as we do a RESET afterwards, but again some CF 
> cards ignore the RESET line.... If the CF card is master it will then 
> wait 32 seconds for the slave response and if that is not present then 
> the BIOS will time out and not recognize the CF card.
> 
> We will implement a hardware workaround for the glitch in future 
> production series but the non standard CF cards will of course still 
> only be master.

This is fine as long as the cards are recognized the same way each time 
the system reboots.

> If a CF card cannot be set to slave then it do not follow the ATA 
> standard and are not recommended to be used in Soekris boards.
> 
> We recommend to use Sandisk CF cards as they seems to always follow the 
> specs and therefore work as expected.

Thanks again.

Darrick
-- 
Darrick Hartman
DJH Solutions, LLC
http://www.djhsolutions.com
http://www.djhsolutions.com/wiki
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