For LinuxCNC versions before 2.7.8 (March 14, 2017), the PPMC driver always forces the port direction change. That does not work with PCIe parallel ports made by Startech, SIIG and Rosewil using the Oxford OXPCIe952 chip.

PCI cards known to work with LinuxCNC < 2.7.8 :

For linuxCNC versions 2.7.8 and later, there is an option on the command line that installs the driver to select whether to force the direction change or not. By default, the driver does NOT force the direction change. To make it force the direction change, add the following text to the command line :

epp_dir=1

The command will be in the file ppmc_load.hal, univstep_load.hal, or univpwm_load.hal, depending on the configuration you are using. It will be of the form :

loadrt hal_ppmc

possibly with additional parameters at the end. Edit it to look like :

loadrt hal_ppmc epp_dir=1

PCI cards known to work with LinuxCNC >= 2.7.8

PCIe cards known to work with LinuxCNC >= 2.7.8

PCI cards that do not work with any version :

NetMos MCS9805 chip

PCIe cards that do not work with any version :

WCH CH382L chip