> On Monday 16 October 2017 11:28:40 Nicklas Karlsson wrote: > > > > > I have been thinking about FPGA for a communication switch, it > > > > would be possible to get perfect timings. Then ordinary micro > > > > controllers could be used for implementing the hardware, the > > > > approach is similar to the new devices with so called Cortex-M-* > > > > PRUs but by using SPI, UART or maybe CAN it is possible to build > > > > more modular and add an insulation barrier. > > > > > > > > The new devices with PRU may be a cheaaper solution for machines > > > > built in very large series. A modular architecture there different > > > > special hardware drivers could be combined is a better solution > > > > then building a lot of different mashines. > > > > > > The Cortex M Costs about $1 or some of them even less. You can buy > > > a complete system on a PCB with connectors. For under $3 shipping > > > included. If you need to make something like a switch or control a > > > few motors these work well. I have several of them. I am using > > > them for motion controller. > > > > Yes I know it very well and also have a few of them. > > > > > In terms of "compute power" They are an order of magnitude above an > > > Arduino. But not even close to a Pi 3 or BBB. > > > > This is good enough for one motor probably with plenty margin. > > > > > ... > > > I'm using one of the boards liked to below to control two motors > > > using PID. I have two PIP loops running and the optical encoder is > > > sending about 11,000 interrupts per second for each motor. I run > > > the PIP loops and get commands over a serial ... > > > > Similar as I do. > > > > > I would not go with an FPGA unless you need very high speed where > > > signals are in the teen's of megahertz at least, up to GHz. The > > > FPGA is much harder to program them an ARM Cortex-M. > > > > > > If I were building a machine tool controller from scratch I'd run > > > much of it on a small computer under Linux then I'd get as many of > > > these Cortex-M chips as required. Each could handle between 2 and 6 > > > axis. > > > > There I am heading. The FPGA could give me as many serial > > communication ports as needed with perfect communication period. > > Second option is to add a Ethercat slave device on each device. > > > > > This sounds appetizing. Lets say you've installed LCNC on a rock64. Now > the rock64 has a 5 Gigabaud usb3 port, and hubs for usb3 stuff are > showing up, which would allow to have something besides the currently > mounted 1Tb seagate usb3 backup disk. With a hub, and I found them as > wide as 13 ports just last week, how hard would it be to make one of > these things with a usb3 interface, just plugging in enough for the > number of axises the machine has?
I am planning something similar, FPGA was my first thought. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
