Erik Christiansen wrote: > On Fri, Oct 26, 2007 at 08:37:47PM -0500, Javid Butler wrote: > >>The real problem is the endpoint device. There will have to be some way to >>decode the signals from the ethernet into the actual drives. It will >>probably be a while before cost effective drives are available with ethernet >>inputs. Until then we will have to use decoders that provide translation of >>the ethernet commands to individual bits such as are on the parallel port. > > > Is it essential that it be ethernet? If Jon's custom host controller had > one or more RS485 ports (preferably 4-wire full-duplex), then any fast > microcontroller with one or more serial ports could potentially serve as > the endpoint controller. > The idea is that 100 mbit/sec ethernet is fast. What other RS485 device do you have that runs that fast? > With on-board multiple-channel PWM generators (e.g. with 64 MHz clock) & > counter/timers to offload the CPU, and interrupt service routines being > the natural order, a reasonably fast uC can handle velocity feedback, > and calculating PID without too much fuss. (But high speed machine > control may be more demanding.) > The main idea of this discussion os to PRESERVE the mode of EMC2, and get around the disappearance of the parallel port. There is no doubt that the entire motion control task, in fact all of EMC2 except the GUI, could be moved to one of these ARM micros. And, by spoon-feeding the G-code in large chunks, there's be no need for a fast I/O channel. But, that is not waht I was trying to do!
> If ethernet is used, it'd surely be necessary to be able to DMA the data > into the micro, or the benefit of 100 Mb/s would be lost. Now we'd need > an ARM chip as axis controller? Incidentally, if linux is to run on the > host, then ARM would be a better choice than the NXP beast? (Though > eCos is well endowed in the ISR area, and more suited to real-time.) This is all handled by these ARM7 micros, they are an entire PC on one chip, except for video. The NXP LPC2300 IS an ARM7 CPU. They also have ARM9 if you need even more. Their problem is getting working silicon out of the lab. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
