Hi Matt On Thursday 16 February 2006 04:05, Matt Timmermans wrote:
A note on setting PERIOD for the quickstep driver: My 3.2 GHz P4 (that doesn't actually run any machines) likes PERIOD=7us. The P266 laptop that runs my Sherline likes PERIOD=15us. The laptop can actually run with PERIOD=10us, albeit slowly, so that's probably the best bet for the 1.x GHz class machines that are often used with EMC and steppers.
With the Celeron 433 that I use for testing, using the mini GUI, I tried 5uSec.. Bogomips reported 66 (426 without EMC running), and KDE was very sluggish. Jogging the A axis could be best described as erratic - The parallel port is a vintage ISA card, which as we know, takes a significant period to write data to, so 5uSec is pushing the limits somewhat. Using a more realistic period of 7.5uSec (146 Bogomips), the computer is a lot more responsive, and rapids can quite easily hit insane levels (for a Sherline). Normally with freqmod, I would have gone for a conservative 20uSec and set the max velocities fairly low.. Going to have to dig out the scope and do some serious back to back testing with a few other computers, perhaps adding some additional data to /proc/emc to characterise the loop times a bit better. In the past, I have used freqmod with periods of less than 10uSec, but found jitter to be problematic... I have a few thoughts on tying quickstep in without duplicating the module init/cleanup routines to bounce of you at a later date. Regards, Paul. -- From the Klingon book of C: Klingon function calls do not have 'parameters' - they have 'arguments' - and they ALWAYS WIN THEM.