Trials and tribulations experienced while learning RaspberryPi + machinekit

This is currently a running log of steps taken to get the machinekit application running on a RaspberryPi3B+...

REFERENCES (Thank you!)

1. http://www.machinekit.io/
2. https://www.raspberrypi.org/downloads/raspbian/
3. https://groups.google.com/forum/m/#!topic/machinekit/wiM-oc7HAms
4. https://www.youtube.com/watch?v=H2XkYI79irQ&t=1s
5. https://www.youtube.com/watch?v=uFbr7xBjItE
6. https://www.youtube.com/watch?v=8lAKXLrmSZo
7. https://lemariva.com/blog/2018/04/rapberry-pi-preempt-rt-kernel-performance-on-rasbperry-pi-3-model-b

Here are the steps performed:

1. Ordered Raspi 3b+ ( skipped the 'expert' installation... :) ) https://www.amazon.com/ELEMENT-Element14-Raspberry-Pi-Motherboard/dp/B07BDR5PDW/ref=sr_1_3?s=pc&ie=UTF8&qid=1544580059&sr=1-3&keywords=raspberry+pi+3+b%2B

2. Ordered / used a 16 GB micro SD card https://www.amazon.com/Kingston-16GB-microSDHC-microSD-SDCS/dp/B079H6PDCK/ref=sr_1_2?s=pc&ie=UTF8&qid=1544580269&sr=1-2&keywords=micro+sd+card&refinements=p_n_feature_two_browse-bin%3A6518303011

3. Ordered / used a USB SD Card adapter https://www.amazon.com/Xit-MicroSD-Reader-Writer-XTSDCR/dp/B00APAKX52/ref=sr_1_1?s=electronics&ie=UTF8&qid=1544580397&sr=1-1&keywords=micro+sd+card+usb+adapter

4. Downloaded a fresh image of Raspbian Stretch w/ Desktop https://www.raspberrypi.org/downloads/raspbian/

5. Unzipped to img file

6. Wrote image file to micro SD card using Etcher https://www.balena.io/etcher/

7. After image file was written, I 'touched' a file 'ssh' in the micro SD 'boot' folder to enable ssh

8. Removed card from USB adapter, inserted into rpi3b+ and booted..

9. Connected the rpi3b+ to my network via a std Ethernet cable

10. Was able to find out the rpi MAC address by looking at my router logs and then I reserved a local IP addresess

11. Used ssh to log into my pi $ ssh [email protected]

12. Following (mostly) reference (2) above, I entered these shell commands:

    $ sudo apt-get -y update

    $ mkdir git

    $ cd git/

    $ git clone --depth=1 https://github.com/raspberrypi/linux -b rpi-4.14.y-rt

    $ cd linux/

    $ KERNEL=kernel7

    $ make bcm2709_defconfig

    $ sudo apt-get install ncurses-base

    $ sudo apt-get install libncurses5-dev libncursesw5-dev

    $ make menuconfig

    $ sudo apt-get install bc

    $ make -j4 zImage modules dtbs

    $ sudo make modules_install

    $ sudo cp arch/arm/boot/dts/*.dtb /boot/

    $ sudo cp arch/arm/boot/dts/overlays/.dtb /boot/overlays/

    $ sudo cp arch/arm/boot/dts/overlays/README /boot/overlays/

    $ sudo cp arch/arm/boot/zImage /boot/$KERNEL.img

    $ sudo reboot -n

    $ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 43DDF224

    $ sudo apt-get dirmngr

    $ sudo apt-get install dirmngr

    $ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 43DDF224

    $ sudo sh -c "echo 'deb http://deb.machinekit.io/debian stretch main' >
    /etc/apt/sources.list.d/machinekit.list"

    $ sudo apt-get update

    $ sudo apt-get install machinekit-rt-preempt

13. On my host, I opened a new terminal and enabled x server access $ xhost +

14. Then I reconnected to the rpi with $ ssh -X [email protected] $ export DISPLAY=192.168.0.113:0.0

15. And at the prompt I was able to start machinekit with the graphic window shown on my host! $ machinekit

SO.... After this initial success, I followed the instructions at http://www.machinekit.io/docs/install/Latency_Test/

and the latency I am seeing seems to be VERY large:

A) For the first test

$ latency-test

the Max jitter while I am not loading the CPU is ~ 60 us (yes, micro-sec)

and when I load the rpi with another application (glxgears) the latency balloons to about 310 us!!!

B) For the second test as shown on the machinekit website

$ latency-test 25us 1ms

This test, under load has

Servo thread:  3.8 us jitter
Base Thread:   190 us jitter

I think these numbers are quite large, so I will investigate...

12/12/2018

From reference (7) I added the additional lines to the /boot/cmdline.txt, and again ran

$ latency-test 125us 2ms

This time, the results were: Unloaded Servo Thread (2ms): 101.5 us Base Thread (125us) 89 us

Loaded Servo Thread (2ms): 3377472 ns Base Thread (125us) 214113 ns

Next, I tried recompiling the 4.14.y-rt kernel w/ 1000Hz timer resolution:

12/14

when using the HAL shell + tutorial I ran into an issue w/

halcmd: loadusr halmeter halcmd: Gtk-Message: Failed to load module "canberra-gtk-module"

sudo apt install libcanberra-gtk-module libcanberra-gtk3-module

12/22

CHANGED TO BEAGLE BONE BLACK

1. https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Flashing_eMMC
2. https://machinekoder.com/machinekit-debian-stretch-beaglebone-black/

Downladed image: wget https://rcn-ee.com/rootfs/bb.org/testing/2018-12-10/stretch-machinekit/bone-debian-9.6-machinekit-armhf-2018-12-10-4gb.img.xz

Unzipped and wrote to micro SD using https://www.balena.io/etcher/

Logged in w/ usr:pass of machinekit:machinekit

$ ssh -X [email protected]

Made a git folder:

$ mkdir /home/machinekit/git

Cloned

https://github.com/machinekit/machinekit.git

into git

Also found this reference

https://github.com/cdsteinkuehler/beaglebone-black-pinmux/blob/hal_pru_generic/pinmux.ods

on BBB:

$ sudo apt-get update

$ sudo apt-get upgrade

$ sudo apt-get install xauth

$ touch ~/.Xauthority

Now you can run ssh on client

$ ssh -v -X [email protected]

$ machinekit

halscope

$ sudo apt-get install libcanberra-gtk-module

https://groups.google.com/forum/#!topic/machinekit/7ZC80xVkfXo

Jun 19 post

Solution to insmod error... https://jetforme.org/2018/04/machinekit-on-bbb/

1. Install from elinux
2. sudo apt-get update
3. sudo apt-get upgrade
4. machinekit

select pru-examples in GUI, (check YES to copy config file) it will fail w/ error

5. Edit newly copied config file in /home/machinekit/configs/pru-examples

$ vim pru-stepper.ini

For the CONFIG line, change to

CONFIG=prucode=/usr/lib/linuxcnc/rt-preempt/pru_generic.bin pru=1 num_stepgens=3 num_pwmgens=1

Save file

6. Restart machinekit

machinekit@beaglebone:$ mkdir git machinekit@beaglebone:$ cd git/ machinekit@beaglebone:~/git$ git clone https://github.com/machinekit/machinekit.git --depth 1

Info re device tree overlays

http://www.weigu.lu/sb-computer/bbb_device_tree/index.html http://derekmolloy.ie/gpios-on-the-beaglebone-black-using-device-tree-overlays/

https://github.com/machinekoder/BBIOConfig

issue w/ pin 9.28

Waiting for /sys/class/uio/uio0 OK P9_28 pinmux file not found! WARNING: GPIO pin not exported, cannot set direction or value! bash: /sys/devices/platform/ocp/ocpP9_28_pinmux/state: No such file or directory Cannot write pinmux file: /sys/devices/platform/ocp/ocpP9_28_pinmux/state CRAMPS.hal:11: program './setup.sh' failed, returned 1 Shutting down and cleaning up Machinekit...

https://groups.google.com/forum/#!topic/beagleboard/EYSwmyxYjdM

added this line to uEnv.txt

cape_enable=bone_capemgr.enable_partno=/lib/firmware/BB-SPIDEV0-00A0.dtbo,/lib/firmware/BB-SPIDEV1-00A0.dtbo

root@beaglebone:/sys/devices/platform/ocp# ls 40300000.ocmcram 48046000.timer 48300000.epwmss driver_override ocp:P8_18_pinmux ocp:P9_23_pinmux 44e07000.gpio 48048000.timer 48302000.epwmss modalias ocp:P8_19_pinmux ocp:P9_24_pinmux 44e09000.serial 4804a000.timer 48304000.epwmss ocp:cape-universal ocp:P8_26_pinmux ocp:P9_26_pinmux 44e0b000.i2c 4804c000.gpio 4830e000.lcdc ocp:l4_wkup@44c00000 ocp:P9_11_pinmux ocp:P9_27_pinmux 44e0d000.tscadc 48060000.mmc 48310000.rng ocp:P8_07_pinmux ocp:P9_12_pinmux ocp:P9_30_pinmux 44e35000.wdt 480c8000.mailbox 49000000.edma ocp:P8_08_pinmux ocp:P9_13_pinmux ocp:P9_41_pinmux 44e3e000.rtc 480ca000.spinlock 49800000.tptc ocp:P8_09_pinmux ocp:P9_14_pinmux ocp:P9_42_pinmux 47400000.usb 4819c000.i2c 49900000.tptc ocp:P8_10_pinmux ocp:P9_15_pinmux ocp:P9_91_pinmux 48022000.serial 481a0000.spi 49a00000.tptc ocp:P8_11_pinmux ocp:P9_16_pinmux ocp:P9_92_pinmux 48024000.serial 481a8000.serial 4a100000.ethernet ocp:P8_12_pinmux ocp:P9_17_pinmux of_node 4802a000.i2c 481ac000.gpio 4a300000.pruss ocp:P8_13_pinmux ocp:P9_18_pinmux power 48030000.spi 481ae000.gpio 4c000000.emif ocp:P8_14_pinmux ocp:P9_19_pinmux subsystem 48038000.mcasp 481cc000.can 53100000.sham ocp:P8_15_pinmux ocp:P9_20_pinmux uevent 48042000.timer 481d0000.can 53500000.aes ocp:P8_16_pinmux ocp:P9_21_pinmux 48044000.timer 481d8000.mmc 56000000.sgx ocp:P8_17_pinmux ocp:P9_22_pinmux

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Downladed image: wget https://rcn-ee.com/rootfs/bb.org/testing/2018-12-10/stretch-machinekit/bone-debian-9.6-machinekit-armhf-2018-12-10-4gb.img.xz

Unzipped and wrote to micro SD using https://www.balena.io/etcher/

Logged in via ssh on host $ ssh [email protected] Logged in w/ usr: machinekit passwd: machinekit

Update / upgrade

$ sudo apt-get update

$ sudo apt-get upgrade

$ sudo apt-get install xauth

$ touch ~/.Xauthority

Edit /boot/uEnv.txt

Uncomment line

disable_uboot_overlay_audio=1 

to disable audio function from IO pins (allows for use as GPIO and SPI)

Reboot

$sudo reboot -n

And login per ssh w/ X windows support

$ ssh -X [email protected]

Make a folder

$ mkdir ~/git

$ cd ~/git

Clone machinekit

$ git clone https://github.com/machinekit/machinekit.git --depth 1

Goto CRAMPS directory

$ cd ~/git/machinekit/configs/ARM/BeagleBone/CRAMPS

Ensure setup.sh is executable with

$ chmod 777 setup.sh

Start machinekit w/ CRAMPS.ini

$ machinekit CRAMPS.ini

Machinekit should start...

FYI, info re. IO pins

https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/cape-universal-00A0.dts

20190102

After some more research, I commented out additional lines of /boot/uEnv.txt

disable_uboot_overlay_emmc=1
disable_uboot_overlay_video=1

since I am using X windows and a microSD card

remote UI https://github.com/scottnortman/machinekit.git

20190125

Due to issues w/ remote UI and high CPU usage, going back to tkemc for now...

Also found a problem with PWM generation; both the PWM component and the PRU PWM (as provided in machinekit) do not work properly; both implements have been tested with the Nomad spindle motor driver controller with poor results...

Therefore, since machinekit allows for calling of python code in their 'real time' implementation, a work around using Adafruit BBIO library is under development...

https://github.com/adafruit/adafruit-beaglebone-io-python