On Sun, 2012-04-15 at 21:23 -0700, Gary P. Fiber wrote: > I need to find the start of this thread. i am running a G540, an Intel > M525MW board with Probotix steppers motors and all 3 axes move fine. I > just need to calibrate them for proper distance and get the homing Hall > effect sensors connected.I am not running the charge pump enabled in the > G540. Am I missing something? > > Gary K8IZ
Dan from the DIY-CNC list was having trouble with trying LinuxCNC. He has a lot of experience with Mach, so expected his Mach set up should work as-is with just the software change. His setup (I think) is a PC with a G540 directly connected to the motherboard port. In trying to sort out what the problem is, a "feature" became apparent. Mach calls for the parallel port to be in EPP mode. To LinuxCNC'ers, EPP is only used for two way communication with FPGA cards. It seems Geckodrive calls for EPP as a trick to turn on drive circuits in the parallel port chip to give a boost to the charge pump signal on pin 16. My experiments so far indicate that parallel ports vary in pin drive capability and in its use. Some might work with EPP, others might get by with a pull-up resistor. For setups using the motherboard port, the BIOS is where to set EPP and has a good chance of working. PCI cards are pretty iffy, and what works (EPP, pull-up, buffer) can vary. PCI cards can be set to EPP with a utility app, but may still not work. The reason you may want to use the charge pump on the G540 is to keep the G540 from moving anything until LinuxCNC wakes up, starts the pump and takes control of the parallel port. Without the pump, the G540 can be active while the PC boots and toggles various pins on the parallel port, before LinuxCNC takes over. This can be extended to other parts of you machine too. http://wiki.linuxcnc.org/cgi-bin/wiki.pl?About_Charge_Pumps -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
