On Sun, Oct 22, 2017 at 5:18 AM, Nicklas Karlsson < nicklas.karlsso...@gmail.com> wrote:
> > > Then it come to longer distances or a bus I think Ethercat is the best. > Then distance is a few inches maybe SPI is a good choice. > Yes, this is pretty much what everyone doing this thinks. SPI generally is not used outside of about one foot, if even that. For those not used to using SPI, It is not really serial. OK the data is sent one bit at a time but if is a FOUR WIRE BUS. and you CAN NOT use differential signaling on SPI in order for it to work outputs need to be "tri-state" and go high impedance when not selected. At most you can use 8 inch cables SPI needs four wire cable and you can't allow bit skew. You would need to invent some heroic engineering methods to run SPI over a long distance at any reasonable speed. Ethernet self clocked so you only need a pair of wires for each direction and Ethernet uses Manchester encoding so it can be isolated with dirt-cheap transformers. The use of the Manchester encoding is what makes it work so well and at such a low cost. Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ 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
