EMC2 running on Raspberry Pi?

double posted for some weird reason?

andypugh wrote:

mungkie wrote:

d took ages to load up axis (I waited 10 minutes then powered down the system as axis seemed almost locked up).

Have you used Axis successfully in the past? I seem to recall mah saying that the Pi didn't really have the processing power to run a graphical GUI. tklinuxcnc or similar lightweight GUI might be a better choice.

Yes, I have always used axis right from my very first experiments I made (the original video of linuxcnc running on pi was made using axis and clicking the buttons to move motors), axis is slow, but not 10 minutes to load slow, it will load in about 25 seconds and does a graphical plot update about once in 0.8 seconds (If anyone can be bothered to try there could be easy methods to add openGL wrapper to the GLES libs to allow hardware accel, not sure if that would cause interupt problems though?). I maybe worth trying the realtime tests in the home directory subfolder to check if there is corruption of the kernel.

Okay, I will not go into too much detail about the nightmare of madness that has occured trying to create an SD card image, It seems though that there could be problems with the sanity of the filesystem or the way that the rpi kernel handles the mmc card.

I have spent over 10 hours in the last couple of days trying to do something that should take less than an hour, and still not succeeded, basically getting a clean image is rather hard to do, so there are more than 50Mb of cruft on the image.

I have tested it and it seems to run, if anyone with better test equipment could give me some feedback that would be useful.

I am just waiting for the file to upload to the web which should take another couple of hours, then I will update the web page to point to the correct file.

Okay web page is updated with new download link, should be a 319Mb download, please let me know if there are any problems with it.

the link page is: soundproofingforum.co.uk/rpi_linuxcnc/raspberrypilinuxcnc.htm

mungkie wrote:

Okay web page is updated with new download link, should be a 319Mb download, please let me know if there are any problems with it.

the link page is: soundproofingforum.co.uk/rpi_linuxcnc/raspberrypilinuxcnc.htm

I am excited about your progress. I am a computer hack that doesn't know much about any kind of programming but would like to see a successful implementation of LinuxCNC on a small platform like the RPi.

I have a RPi and I downloaded the image file, wrote it to my SD card and booted up the Pi. It booted fine but when I went to start the x-server the screen went blank and it stopped doing anything that I could tell. Left it that way for about 30 minutes and no change. I tried it twice with the same results. Here is what I did:

1- Power up the Pi
2- login using pi, and raspberry as the username and password.
3- "startx"

The Pi flashed some instructions on the screen, went black and then sat there.

Don't know if this helps or hurts. Really hope you get this baby working.

As an FYI, I have a CNC benchtop mill I could try it on and would be more than happy to do so. Right now the mill is hooked up to the typical old desktop running LinuxCNC 2.5. The way I have it set up right now it needs a maximum step rate of 24kHz for max rapid of 180 inches/min (0.2" pitch screw, 8 microstepping, 200 step/rev steppers). I don't really need the mill to run that fast but I do like that speed.

Hope some of this helps.

John B.

109jb wrote:

I tried it twice with the same results. Here is what I did:

1- Power up the Pi
2- login using pi, and raspberry as the username and password.
3- "startx"

The Pi flashed some instructions on the screen, went black and then sat there.
John B.

I think maybe the web page instructions are not so clear as I changed the window manager that X uses, the twm window manager which requires you to left click and hold down your mouse button for the menu to appear!

Also for some reason X does not show the cursor pointer until the mouse button has been clicked, and also the system is quite slow so it may take upto 20 seconds after the screen blanks before X responds to mouse input. Once you have left click and hold the menu should appear select debian->applications->shells->bash and then release the left mouse button.

3 seconds then a window outline should appear, click where you want the shell window to appear, then twm has a focus follows pointer policy so the mouse cursor must be over the window to allow you to input events, make sure the pointer is in the window then type 'cd emc*', then type './launch.sh'. You should then get the linuxcnc configuration selector window appear after 10 seconds (twm will give window outline and you must click where you want window placed). from the configuration window you MUST select the rpi->stepper_mm option, and read the instruction in the right window pane (the pin defs are very badly formatted). Click the 'OK' button the selection window will disappear and the splash screen show up, then Axis window should appear after 30 seconds (maximum 50 seconds if not then there is some serious error so reboot and start again).

I think that there is still problems with the RT_PREEMPT kernel and that is maybe causing corruption due to incorrect handling of mmc reads when realtime interupt occurs, this maybe is causing strange behaviour of X when loading programs from the SD card, also when loading axis sometimes seems to pause until a mouse button is clicked within the window(if a small icon appears in top left saying 'axis' double click it and the window should fullscreen then try clicking on the right hand opengl plot window.


As said this is an early test just to get feedback on if the driver is missing steps generated by the motion controller because the DMA program is losing synchronisation with the servo thread. It is really for experts only, although it does drive motors you should be extreamly careful as the driver does not currently take any input for endstops or estop and you should not try connecting any feedback to the rpi gpio pins as they ARE NOT 5volt tolerant and you will destroy the pin (you can add a couple of resistors to an input to voltage divide the signal, but you have to work that out yourself)


REITERATE THIS IS NOT FOR BEGINNERS, IF YOU CONNECT THINGS INCORRECTLY YOU COULD HURT YOURSELF OR DESTROY YOUR RASPBERRY PI COMPUTER.

DO NOT CONNECT ANY ELECTRONICS AS INPUTS TO THE RPI AND DO NOT USE ANY 5VOLT ELECTRONICS DIRECTLY TO THE GPIO PINS.

Thanks. I will give that a try this afternoon.

Right now I am just looking to get it running in sim mode not hooked up. If successful with that I will see about hooking to the mill. I would most likely connect to my current breakout board by making a cable to go from the GPIO to the DB25 on the BOB. The BOB has optos, and I would only run to the pins I absolutely need to test the mill. Do you have some pins on the GPIO set up for 3 axis motion. Outputs only is fine. If you do could you give a pinout of what you have defined?

109jb wrote:

Thanks. I will give that a try this afternoon.

Right now I am just looking to get it running in sim mode not hooked up. If successful with that I will see about hooking to the mill. I would most likely connect to my current breakout board by making a cable to go from the GPIO to the DB25 on the BOB. The BOB has optos, and I would only run to the pins I absolutely need to test the mill. Do you have some pins on the GPIO set up for 3 axis motion. Outputs only is fine. If you do could you give a pinout of what you have defined?

Read the README and .hal and .ini files in configs/rpi directory it should give you the details you need. Also the pins used will print in the terminl window when loaded.

Beware that setting gpio pins that are not defined on the P1 and P6 headers could damage your system and the driver does not mask anything or error check.