[Linux-parport] OxPCIe952 EPP

[Jon Elson]

Hello,

I saw your post on linux-parport from Dec 2014 about the 
Oxford 952 chip.

I have been selling motion control boards using the parallel 
port in EPP mode since 2001.
I have been using roughly the same code to drive the 
parallel port all that time, from
ISA multi-I/O chips through PCI to PCIe.  I have only tried 
a couple PCIe parports.
I just discovered the same problem you had with reading at 
the PC end.  I did use a logic analyzer to observe the 
problem.  To read, bit 5 of the ctrl reg is set to 1, and 
then the parport chip will not produce a pulse
on the DATASTB/ pin when the EPP data port register is read 
with an INB instruction.

I don't know how Oxford Semi. could have screwed up this 
badly! They have been making PCI multi-I/O chips for at 
least a decade and they all worked.  I used to recommend 
SIIG PCI parallel ports as the most reliable, and they all 
used Oxford chips.  As far as I can tell, these PCIe chips 
will not work with any printer or scanner that actually uses 
EPP mode.

I'm amazed that there aren't more people having problems 
with this.

I found the Syba boards with the NetMos 9900 chip work fine 
with my code and my boards.

Jon