> > *It is also possible to directly address the GPIO pins from the Arm > processor, although there is some delay in the interconnect system of the > chip* >
This is true of the PRU as well, for many of the GPIO pins. However, the largest issue the ARM processor has to contend with, is the operating system. So, a userland application that directly accesses GPIO registers in order to achieve what needs being done. Can often be performant / deterministic enough. A Linux userland application can never be deterministic 100% of the time - However. A PRU application on the other hand, can be. On Fri, Dec 4, 2015 at 3:53 PM, jmelson <[email protected]> wrote: > > > On Sunday, November 22, 2015 at 11:10:33 AM UTC-6, Bruce Boyes wrote: >> >> If you google you can find multiple CNC projects based on BBB, such as >> this list >> http://blog.machinekit.io/p/hardware-capes.html#BeagleCNC >> Google is your friend (in this case). >> >> >> Yes, machinekit is a very sophisticated G-code itnerpreter and motion > control program. It uses the built-in PRU microcontroller to generate step > pulses at high rates and with accurate timing. There is a "CRAMPS" board > that holds up to 6 Pololu-style stepper driver modules. It is mostly aimed > at 3D printers, but can be used for any small machine that uses stepper > motors. The CRAMPS board plugs onto the BBB like a larger cape. The PRU > has direct connection to a limited set of I/O pins. > > It is also possible to directly address the GPIO pins from the Arm > processor, although there is some delay in the interconnect system of the > chip. This still allows you to control them directly from a C or other > program with under 200 ns delay. It does require your program to run with > SU privileges. It also requires you to set up the pin mapping, which is > not documented as well as it ought to be. > > Jon > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
