Hi Bari, >> speed low latency it's now PCs w/o parallel ports and built in video that >> makes a PC a bit of a crap shoot. > Onboard video hasn't been an issue with latency for the past 10 years or > so. I have been using AMD motherboards for the past 20 years without any > onboard video causing latency issues.� I get $10 PCIe LPT cards for my > x86 PC's all the time that work well with software stepping and a $10 > BOB. If it says WCH CH382L on the chip it usually works, even with EPP > and a Mesa card. EPP is only required for the LPT port to work with a > Mesa card. EPP is not required for software stepping to a BOB.� This > driver was added to the kernel for Dev. ID 3050, Date: Sat, 26 May 2018, > Kernel 4.14 > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/patch/drivers/parport/parport_serial.c?id=c9a104e23cb8ff37ddeb788f7d5 > 7b3b8d1a030ab
When I installed the latest Linux CNC last fall onto several different Lenova PCs they all failed the latency test for stepping past about 25kHz. Adding external low profile video boards made it even worse. I bought 3 different cards that fit those boxes. The dual boot system ran WIN-XP and MACH3 with step rates up to 75kHz without issues while LinuxCNC could not. The end result was to choose either an Ethernet Smooth Stepper or MESA 7i92H. The MESA was cheaper so I went with that. As I understand it I'm not alone. The faster PCs if anything now more than ever require an external step generator. In the Windows world MACH4 can't even use the USB Smooth Stepper that MACH3 can on processor 10x faster than the WIN-XP running my CNC router. I think basically the fact is a general purpose computer board that runs Linux still needs some sort of external step generator hardware interface. Either through Ethernet, SPI, USB or multiplexed I/O. Personally I think it's nuts to try and re-invent the LinuxCNC (or MachineKit) wheel to create a dedicated single board solution to run milling machines. They already exist for between $200 to $400 with LCD display, keypad and outputs for stepper motors from China. And there are people that swear by those. John Dammeyer _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
