сб, 15 черв. 2019 о 18:01 Peter C. Wallace <[email protected]> пише:
> > I've had LinuxCNC running 24/7 on the 7C80+RPI for about 11 months now > with no > hardware issues. This is with a 40 pin cable about 2" long between the RPI > and > 7C80. If you have interface problems. its very likely a SI ( Signal > Integrity ) > issue with the cabling. > Thanks for your reply! I actually had a decent link when 7i90HD was not connected to any external hardware. But when I tried to control some steppers as I did with Beaglebone, it was a disaster. > > The (7C80,7C81,7I90) SPI interface uses the FPGAs GCLK. This means it can > run up > to 50 MHz or so with a fast host, but it does require good signal > integrity. > This is great. So when are 7Cs expected in the store? And what is the price range? For random/longer cable connections using a async SPI interface in the FPGA > that > simulates the synchronous interface would allow better tolerance of SI > issues ( > by oversampling / filtering the clock and data in signals ) at the cost of > lowering the maximum clock speed to say 8-10 MHz. I have not bothered with > this > since it works reliably with short cables (Actually it works with longer > cables > if the clock source impedance is correct for proper series termination, I > can > drive a 7I90 in SPI mode at 50 MHz send/recv with another FPGA card and a > 2 foot > cable) > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
