raspberry as driver-hardware?

hi all,

is it possible, to use a raspberry as a "slave-stepper-driver-hardware" via
linuxcnc (and the ethercat-driver or something else)?

I've got a standalone-solution (linuxcnc on raspberry) working.

but I'm searching for a solution, to use the rasberry and its GPIO just as
IO-ports.

anyone knows whether it for it is already a solution?

regards

wicki

"arduino is done by a user named DaBit"

is this the cheapest hardware-port-solution?

I have several mills, 3d-printers, lasers and mini-PC here - but only one
mini-PC with a centronics. (the mini-PCs have no free slot)
and I don't want to buy several mesa-boards - if each one is more expensive
than the rest of the other hardware....

"www.r-digital.it/index.php?main_page=pro...cbec547rqmn5f7vjt1u3"

yes, I'm using a one like that.
but it often make problems, because of bad contacts.

what I'm searching for, is a cheap semi-realtime
"ether2centronics"-solution.
if nothing already exists, I will try to check out, what
is possible with a rasPI.

You shoudt get a look on the module of Estlcam
this gives you a fast solotion and 40USD

BUT better to spent some more money and go for a 5Axis Mach3 BOB and the mesa 7i92
This will speed you up to over 5m/min

pl7i92 wrote:

You shoudt get a look on the module of Estlcam
this gives you a fast solotion and 40USD

BUT better to spent some more money and go for a 5Axis Mach3 BOB and the mesa 7i92
This will speed you up to over 5m/min

estlcam is a software-solution, as I know?
did you mean, this hardware is able to work with linuxcnc?

www.amazon.de/USB-CNC-Schrittmotor-Steue...8-1&keywords=Estlcam

the speed has not my highest proirity. a slow driver is OK for me.


I just made some tests:
I tried to send UDP-packets with 5 bytes payload from an
desktop-PC to a directly connected rasPI 3.
more than 50k of such packets per second are possible.

so, 20k packets/sec in both directions should also be possible.
even if the communication is done over raw sockets without
IP-overhead.....

that should be enough for a 4-axis-cnc in 16-microstep-mode.

I think, I'll give it a try

if I believe one big searching-machine, the I/O-capabilities of
the raspbery GPIO should by much more as I need:

Language Library Square wave
Python RPi.GPIO 70 kHz
Python wiringpi2 bindings 28 kHz
Ruby wiringpi bindings 21 kHz
C Native library 22 MHz

for a high speed raw ethernet communication C is needed anyway.

I think, on a pc-board with an lpt-port one external thread is able to handle
this communication without any changes in the linuxcnc-code.
but if the board has no port (and also no port-latch), it won't work
without some changes in it.

... to be continued....

wicki wrote:

... to be continued....

ok...
what have I done?

I wrote a realtime-thread for rasPI which is listening and waiting for packets on its MAC-adress.
the master on the linuxcnc-PC is sending the port-data of its 0x378-lpt-port by another thread.
whatever comes in as payload is set to the GPIO of the rasPI.

its a direct connection without router or hub. the rasPI is able to receive about 30k packets/second:
17:52:19 100k packtes received.
17:52:22 100k packtes received.
17:52:25 100k packtes received.
17:52:28 100k packtes received.

then I put the a-DIR and a-STEP signals from the raspPI to the china TB6600 input and
a stepper to the output.

it works, as if it were conected directly to the LPT-port.

I will test the behaviour with more the one stepper next days.

but there is an upcoming question:

it the motherboard of the linuxCNC-PC has no LPT-port - how can I geht
the port-status without touching the linuxCNC-source?

any hints or ideas?