Ian Cameron (I.A.Cameron@open.ac.uk)
Tue, 21 Sep 1999 17:36:46 +0100
> > After much messing around, and to my great embarrassment, I have found the
> > solution to my Zip drive in PS/2 mode problem.
> > It's nothing to do with the driver, but an undocumented jumper on the dual
> > parallel card marked HI/LOW. You might have guessed by now that this ties the
> > end of the pull up resistors to either 0V or +5V, and for some bizarre reason
> > the card is supplied with this jumper set to low! It's only today when I took
> > the card out to try changing the chips around that I noticed it...
> > Why the default is low when the spec says pins pulled high I don't know, but I
> > do know I'm glad it's all sorted out, even if I did waste countless hours
> > inserting printk() statements into the ppa code in an attempt to debug it!
> I'm glad to see this resolved. PLEASE post the full details of this
> card so we can recognise this problem if it arises again.
Okay, here are all the card details I can find:
This no name dual parallel port 16 bit ISA card is marked 4011 (model number),
the main (large) chips being marked SUN1688. The following jumpers are
present on the board: JP2, port 1 I/O address. JP3, port 1 IRQ. JP4, port 1
bi-directional/uni-directional selection. JP5, port 2 I/O address. JP6, port
2 IRQ. JP7, port 2 bi-directional/uni-directional selection. JP8, ports 1
and 2, low = pull up resistors tied to ground, high = pull up resistors tied
The default setting for the pull up resistors is low for some reason, it
should usually be high. Change this jumper to high (HI) to operate the card
successfully with most peripherals that you're likely to attach to it.
Note: There's a single port version of this board which is called 4010.
When using the Zip PPA driver under Linux, incorrect setting of the pull up
resistors may result in an error like this:
ppa: Version 2.03 (for Linux 2.2.x)
ppa: Found device at ID 6, Attempting to use EPP 16 bit
ppa: Found device at ID 6, Attempting to use PS/2
ppa: Communication established with ID 6 using PS/2
scsi0 : Iomega VP10 (ppa) interface
scsi : 1 host
Kernel panic: scsi: unsupported message byte 187 received
In swapper task - not syncing
Your machine will lock up solid, and require a reset from this point.
Hope this helps somebody...
-- Cheers, Ian.
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