LinuxCNC on Raspberry Pi 5

Hello all, 
first thanks so much for building this image - it really works nicely (although I still need to get my touchscreen working but assuming this is just a driver issue).

The main question I have before connecintg and configuring a MESA card is that my latency looks decidedly wrong - I am wondering if I have the RT kernel enabled at all? When I make uname -r, I get this, which doesn't mention RT:
6.6.28+rpt-rpi-2712

All I did was load the GDrive image a few posts ago, and run a update && upgrade.

Is there any way to check and correct?
 

Yeah, that's a normal (non-RT)  kernel

well, that explains that. I found the in an earlier post the command to install the rt kerne (I think), but I do seem to have the RT kernel already installed because a command
sudo apt install -y linux-image-rt-arm64 linux-headers-rt-arm64
returns a "already at newest version".

But I can't seem to figure out from earlier posts what command instructs to use this kernel?

Thanks for your help!

The <SHIFT> key may drop the Pi into diagnostic boot mode.  <ESC> likewise does not work on the Rpi.  From what I'm reading at places like raspberrypi.stackexchange.com/questions/...which-kernel-to-load changing the kernel is more than tricky on the Pi and involves moving/building kernel images manually and editing config.txt.  It would certainly be easiest to just use the ready-made Debian Rpi 4/5 LinuxCNC build found here: linuxcnc.org/downloads/  Just burn it using your favorite flashing software (Rpi Imager, Balena Etcher, etc.)

Do note that the Rpi 5 uses a new and incompatible SPI chip, so vendor boards which use SPI are currently a no-go.  Rpi said they may release the details of their new chip sometime in the future, but not anytime soon.

StoneB wrote:

Hello all, 
first thanks so much for building this image - it really works nicely (although I still need to get my touchscreen working but assuming this is just a driver issue).

The main question I have before connecintg and configuring a MESA card is that my latency looks decidedly wrong - I am wondering if I have the RT kernel enabled at all? When I make uname -r, I get this, which doesn't mention RT:
6.6.28+rpt-rpi-2712

All I did was load the GDrive image a few posts ago, and run a update && upgrade.

Is there any way to check and correct?

 

Blindly running an update is not a good idea.

The easiest way is to reflash the image. The kernel really should have been "pinned" to prevent updates. The RT kernel is a "custom" one.
So you really shouldn't be updating, it's fine as is.

If you are the type that "must update" read this
www.snel.com/support/how-to-block-packag...l-updates-in-debian/

Thanks for the pointer - updates are disabled

In the meantime, I managed to put a new RT kernel on: looks much better, right?
I followed the github.com/by/RT-Kernel instructions - probably not ideal as you, but I avoided a reinstall (and it's kernel 6.9.1 :D)...

Hi No I have not make any progress but i conekt a home switch to my Gpio pin for spindle index and when i click manualy on the switch the reading moved a bit , when I click fast i reach 60 rpm o the display so I think the problem is in the filter for the signal , i have to optical sensor and there are signal from both index and fase a, so my problem is to find the value for this part and if anybody can help me sort it out i be very happy ./krister

Problem with indexpuls on spindle ,The reading on the imput 10 GPIO 22 for the indexpuls is 0.5 volt ac and the reading on input 11 GPIO 24 is 0.2 v ac , I dont know
the settings in HAL file for this and I need help to find the right values for correkt reading in the Hal file ,i dont know the right place to play with these numers , I can read the signal on the input at the chinese breakout bord and after that the signal disepere nothing in the Halmeter or Halscope. My set up is Raspberry pi 5 and this byte2bot.com/blogs/instructions/setting-...-the-pi-parallel-hat and this byte2bot.com/products/5-axis-cnc-interfa...tepper-motor-drivers


the HAL file

# Generated by stepconf 1.1 at Mon Mar 18 18:19:52 2024
# If you make changes to this file, they will be
# overwritten when you run stepconf again
loadrt [KINS]KINEMATICS
loadrt [EMCMOT]EMCMOT base_period_nsec=[EMCMOT]BASE_PERIOD servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[KINS]JOINTS
#loadrt hal_parport cfg="0 out"
#setp parport.0.reset-time 5000
loadrt stepgen step_type=0,0
loadrt encoder num_chan=4
loadrt abs count=1
loadrt scale count=1
loadrt lowpass count=1
loadrt near
loadrt pwmgen output_type=1
loadrt classicladder_rt numPhysInputs=15 numPhysOutputs=15 numS32in=10 numS32out=10 numFloatIn=10 numFloatOut=10
#loadrt charge_pump

#loadrt hal_pi_gpio dir=0x13407 exclude=0x1F64BF8

loadrt hal_gpio inputs=PIN22,PIN32,PIN33,PIN24,PIN26 outputs=PIN12,PIN37,PIN21,PIN19,PIN23,PIN29,PIN31,PIN35,PIN11,PIN16,PIN13,PIN18




#addf parport.0.read base-thread
addf stepgen.make-pulses base-thread
#loadrt sum2 count=1
#loadrt not count=1


addf encoder.update-counters base-thread
addf pwmgen.make-pulses base-thread
#addf parport.0.write base-thread
#addf parport.0.reset base-thread

addf stepgen.capture-position servo-thread
addf encoder.capture-position servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread
addf classicladder.0.refresh servo-thread
addf stepgen.update-freq servo-thread
addf pwmgen.update servo-thread
addf abs.0 servo-thread
addf scale.0 servo-thread
addf lowpass.0 servo-thread

addf hal_gpio.read base-thread
addf hal_gpio.write base-thread
addf near.0 servo-thread

net spindle-cmd-rpm => pwmgen.0.value
net spindle-on <= spindle.0.on => pwmgen.0.enable
net spindle-pwm <= pwmgen.0.pwm
setp pwmgen.0.pwm-freq 100.0
setp pwmgen.0.scale 1166.6666666666665
setp pwmgen.0.offset 0.11428571428571428
setp pwmgen.0.dither-pwm true
net spindle-cmd-rpm <= spindle.0.speed-out
net spindle-cmd-rpm-abs <= spindle.0.speed-out-abs
net spindle-cmd-rps <= spindle.0.speed-out-rps
net spindle-cmd-rps-abs <= spindle.0.speed-out-rps-abs
net spindle-at-speed => spindle.0.at-speed
net spindle-cw <= spindle.0.forward

################ Spindle index #########################
# Add the encoder to HAL and attach it to threads.
#loadrt encoder num_chan=4
#addf encoder.update-counters base-thread
#addf encoder.capture-position servo-thread

# Set the HAL encoder to 20 pulses per revolution.
setp encoder.3.position-scale 20

# Set the HAL encoder to non-quadrature simple counting using A only.
setp encoder.3.counter-mode true

# Connect the HAL encoder outputs to LinuxCNC.
net spindle-position encoder.3.position => spindle.0.revs
net spindle-velocity encoder.3.velocity => spindle.0.speed-in
net spindle-index-enable encoder.3.index-enable <=> spindle.0.index-enable

# Connect the HAL encoder inputs to the real encoder.
net spindle-phase-a encoder.3.phase-A # <= hal_gpio.PIN24-in
net spindle-phase-b encoder.3.phase-B
net spindle-index encoder.3.phase-Z # <= hal_gpio.PIN22-in-not
setp encoder.3.position-scale 20.000000 #
setp encoder.3.counter-mode 1 #

setp lowpass.0.gain 0.05

net spindle-position encoder.3.position => spindle.0.revs
#net spindle-velocity-feedback-rps encoder.3.velocity => spindle.0.speed-in
net spindle-index-enable encoder.3.index-enable <=> spindle.0.index-enable
net spindle-phase-a encoder.3.phase-A
net spindle-phase-b encoder.3.phase-B
net spindle-index encoder.3.phase-Z

#net estop-out => parport.0.pin-01-out
net xstep => hal_gpio.PIN21-out
#setp parport.0.pin-02-out-reset 1
net xdir => hal_gpio.PIN19-out
net ystep => hal_gpio.PIN23-out
#setp parport.0.pin-04-out-reset 1
net ydir => hal_gpio.PIN29-out
net zstep => hal_gpio.PIN31-out
#setp parport.0.pin-06-out-reset 1
net zdir => hal_gpio.PIN35-out
#net astep => hal_gpio.PIN11-out
#setp parport.0.pin-08-out-reset 1
#net adir => hal_gpio.PIN16-out
net spindle-cw => hal_gpio.PIN11-out
net spindle-pwm => hal_gpio.PIN16-out
net xenable => hal_gpio.PIN37-out
net spindle-index <= hal_gpio.PIN22-in
net spindle-phase-a <= hal_gpio.PIN24-in
net min-home-x <= hal_gpio.PIN26-in
net min-home-z <= hal_gpio.PIN33-in





#############################################################
setp stepgen.0.position-scale [JOINT_0]SCALE
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 35000
setp stepgen.0.dirsetup 35000
setp stepgen.0.maxaccel [JOINT_0]STEPGEN_MAXACCEL
net xpos-cmd joint.0.motor-pos-cmd => stepgen.0.position-cmd
net xpos-fb stepgen.0.position-fb => joint.0.motor-pos-fb
net xstep <= stepgen.0.step
net xdir <= stepgen.0.dir
net xenable joint.0.amp-enable-out => stepgen.0.enable

net min-home-x => joint.0.home-sw-in
net min-home-x => joint.0.neg-lim-sw-in
net min-home-x => joint.0.pos-lim-sw-in

setp stepgen.1.position-scale [JOINT_1]SCALE
setp stepgen.1.steplen 1
setp stepgen.1.stepspace 0
setp stepgen.1.dirhold 35000
setp stepgen.1.dirsetup 35000
setp stepgen.1.maxaccel [JOINT_1]STEPGEN_MAXACCEL
net zpos-cmd joint.1.motor-pos-cmd => stepgen.1.position-cmd
net zpos-fb stepgen.1.position-fb => joint.1.motor-pos-fb
net zstep <= stepgen.1.step
net zdir <= stepgen.1.dir
net zenable joint.1.amp-enable-out => stepgen.1.enable
net min-home-z => joint.1.home-sw-in
net min-home-z => joint.1.neg-lim-sw-in
net min-home-z => joint.1.pos-lim-sw-in

net estop-out <= iocontrol.0.user-enable-out
net estop-out => iocontrol.0.emc-enable-in

loadusr -W hal_manualtoolchange
net tool-change iocontrol.0.tool-change => hal_manualtoolchange.change
net tool-changed iocontrol.0.tool-changed <= hal_manualtoolchange.changed
net tool-number iocontrol.0.tool-prep-number => hal_manualtoolchange.number
net tool-prepare-loopback iocontrol.0.tool-prepare => iocontrol.0.tool-prepared

# Load Classicladder without GUI (can reload LADDER GUI in AXIS GUI
loadusr classicladder --nogui custom.clp

I have been using the latest image on a Raspberry Pi and it is working surprisingly well.  I paired it with a Mesa 7i96S ethernet card and the results are amazing. 
10 years ago I rebuilt my CNC with an Atom/PCIe setup, and I intend to upgrade again with the Pi.

The only hiccup left with the setup is the touch screen driver with Wayland. 
It works very well for single touches, and can clearly detect all 10 fingers when I runbut Axis doesn't seem to understand anything but basic touches.
Chromium and other windows understand the scroll/zoom gestures correctly, so I believe it has to do with TK not being up to date with libinput.
I am currently exploring adding a python "shim" to Axis to allow it to use libinput directly.  I will post more soon.

Hardware:
5 Axis CNC, Pi5, Mesa 7i96S, 1920x1200@60 HDMI display, (bare panel with driver board), WHB04B-6 pendant, custom built servo drivers, WJ200 spindle VFD, mist/flood/probe/etc.