On 05/14/2019 11:46 AM, Gene Heskett wrote:
On Tuesday 14 May 2019 12:03:34 pm John Dammeyer wrote:
Why is there so much resistance to using the Beaglebone?
Because it actually has very little in common with the intel code. It
may be a good deal, but it also requires learning all about the care and
feeding of a completely different architecture.
Have you ever looked at the X86 machine code? There is a
TINY bit of it in low-level drivers that access the parallel
port. Otherwise, in LinuxCNC, there is ZERO machine code in
the source.
Even in the above mentioned drivers, it is not actually REAL
X86 code, but macros that work as if it was, to push and
pull bytes to/from the parallel port.
I have written machine code for the Bone's PRU for special
applications. It is GREAT having a 32-bit CPU that can
toggle I/O pins in 5 ns. But, for LinuxCNC motion control,
you DON'T have to ever look at that. Charles Steinkuehler
has done the heavy lifting, and step generators, encoders
and PWM generators are already implemented.
So, if you want to run a few axes with drives that can be
controlled with step and direction signals, the Beagle Bone
is a VERY simple solution. Small, low cost, flexible.
You need a Bone for $65, a micro-SD card for $12 and maybe a
stepper "cape", I sell one for $80 that holds up to 6
Pololu-style stepper drivers. You can link to it through
the USB port or through Ethernet, and display the GUI on a
laptop or desktop.
Some of the resistance is that the Bone uses Machinekit,
which is a fork of LinuxCNC, and is not as well documented
or supported as LinuxCNC is. However, a special distro kit
is being maintained as a mainline distribution by Robert C.
Nelson. You get a micro-SD card, plug it into a USB SD card
reader, and run a script on RC Nelson's web site, and in
about 20 minutes, the SD card is ready to insert into the
Bone and boot it. You can connect a keyboard, mouse and
HDMI monitor and set up the network, etc. that way, or use
some other tools to get it on the net.
For general use, it is ready to go except for the network
configuration. For development, you will need to load some
packages and the LinuxCNC source tree.
Yes, I know my way around the Bone and Machinekit, but 95%
of what you know about X86 LinuxCNC will be ENTIRELY the same!
Jon
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
