From: dan...@austin.rr.com To: "Les Newell" Cc: Sent: Wednesday April 10 2019 1:33:31PM Subject: Re: [Emc-users] Hardware emcmot?
From: "Les Newell" To: "Danny Miller" Cc: Sent: Wednesday April 10 2019 12:55:14PM Subject: Re: [Emc-users] Hardware emcmot? Moving just emcmot is not really practical but moving the whole realtime side to another processor shouldn't be too hard. If I remember correctly the CMS/NML communication subsystem already has network functionality. Of course in that case you'd probably need your external processor to be running some sort of Linux. Les On 10/04/2019 17:10, Danny Miller wrote: > I have been wondering- can emcmot be separated from the HAl and > emctask and become a true dedicated realtime stage to control the joints? > > The shared memory FIFOs could be replaced with like an ethernet link > to the hardware RAM. You'd probably load a DMA buffer and just let it > flow, there's some minor latency but there's not a realtime requirement. > > There are cheap high freq MCUs with single-cycle hardware double > multiply/add and gobs of memory. It would have to be coded in non-OOP > C and I greatly prefer hardware interrupt-driven strategies over RTOS. > > Danny ----------------------------------------- Actually I *don't* want to run a form of Linux. Since it's dedicated HW, the tasks can be hardcoded for bare metal and stored in flash and directly load the STEP/DIR pins with SPI data which does precise, synchronized step-outs.. This is leaner, simpler, more reliable and the latency can be very low and consistent (although LinuxCNC on Preempt-RT is already all of that for my machine). This would require somewhat extensive modification of code. Microcontrollers typically use C and cannot handle C++'s OOP nor dynamic memory allocation. However, static mem allocation should be fine and, like I say, faster and lower latency. Converting objects to non-OOP code is usually pretty straightforward. Danny _______________________________________________ Emc-users mailing list Emcfirstname.lastname@example.org https://lists.sourceforge.net/lists/listinfo/emc-users