[Linux-parport] OxPCIe952 EPP

Jon Elson elson at pico-systems.com
Tue Apr 12 18:06:52 PDT 2016

I saw Matwey Kornilov's 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 he 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, and needs to ID the printer.

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.


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