mirror of https://github.com/Desuuuu/klipper.git
198 lines
8.9 KiB
Markdown
198 lines
8.9 KiB
Markdown
# RPi microcontroller
|
|
|
|
This document describes the process of running Klipper on a RPi
|
|
and use the same RPi as secondary mcu.
|
|
|
|
## Why use RPi as a secondary MCU?
|
|
|
|
Often the MCUs dedicated to controlling 3D printers have a limited and
|
|
pre-configured number of exposed pins to manage the main printing
|
|
functions (thermal resistors, extruders, steppers ...).
|
|
Using the RPi where Klipper is installed as a secondary MCU gives the
|
|
possibility to directly use the GPIOs and the buses (i2c, spi) of the RPi
|
|
inside klipper without using Octoprint plugins (if used) or external
|
|
programs giving the ability to control everything within the print GCODE.
|
|
|
|
**Warning**: If your platform is a _Beaglebone_ and you have correctly followed the installation steps, the linux mcu is already installed and configured for your system.
|
|
|
|
## Install the rc script
|
|
|
|
If you want to use the host as a secondary MCU the klipper_mcu process must run before the klippy process.
|
|
|
|
After installing Klipper, install the script. run:
|
|
```
|
|
cd ~/klipper/
|
|
sudo cp "./scripts/klipper-mcu-start.sh" /etc/init.d/klipper_mcu
|
|
sudo update-rc.d klipper_mcu defaults
|
|
```
|
|
|
|
## Enabling SPI
|
|
|
|
Make sure the Linux SPI driver is enabled by running sudo raspi-config and enabling SPI under the "Interfacing options" menu.
|
|
|
|
## Building the micro-controller code
|
|
|
|
To compile the Klipper micro-controller code, start by configuring it
|
|
for the "Linux process":
|
|
```
|
|
cd ~/klipper/
|
|
make menuconfig
|
|
```
|
|
In the menu, set "Microcontroller Architecture" to "Linux process," then save and exit.
|
|
|
|
To build and install the new micro-controller code, run:
|
|
```
|
|
sudo service klipper stop
|
|
make flash
|
|
sudo service klipper start
|
|
```
|
|
|
|
If klippy.log reports a "Permission denied" error when attempting to connect
|
|
to `/tmp/klipper_host_mcu` then you need to add your user to the tty group.
|
|
The following command will add the "pi" user to the tty group:
|
|
```
|
|
sudo usermod -a -G tty pi
|
|
```
|
|
|
|
## Remaining configuration
|
|
|
|
Complete the installation by configuring Klipper secondary MCU
|
|
following the instructions in
|
|
[RaspberryPi sample config](../config/sample-raspberry-pi.cfg) and
|
|
[Multi MCU sample config](../config/sample-multi-mcu.cfg).
|
|
|
|
## Optional: Identify the correct gpiochip
|
|
|
|
On Rasperry and on many clones the pins exposed on the GPIO belong to the first gpiochip. They can therefore be used on klipper simply by referring them with the name `gpio0..n`.
|
|
However, there are cases in which the exposed pins belong to gpiochips other than the first. For example in the case of some OrangePi models or if a Port Expander is used. In these cases it is useful to use the commands to access the _Linux GPIO character device_ to verify the configuration.
|
|
|
|
To install the _Linux GPIO character device - binary_ on a debian based distro like octopi run:
|
|
```
|
|
sudo apt-get install gpiod
|
|
```
|
|
|
|
To check available gpiochip run:
|
|
```
|
|
gpiodetect
|
|
```
|
|
|
|
To check the pin number and the pin availability tun:
|
|
```
|
|
gpioinfo
|
|
```
|
|
|
|
The chosen pin can thus be used within the configuration as `gpiochip<n>/gpio<o>` where **n** is the chip number as seen by the `gpiodetect` command and **o** is the line number seen by the` gpioinfo` command.
|
|
|
|
***Warning:*** only gpio marked as `unused` can be used. It is not possible for a _line_ to be used by multiple processes simultaneously.
|
|
|
|
For example on a RPi 3B+ where klipper use the GPIO20 for a switch:
|
|
```
|
|
$ gpiodetect
|
|
gpiochip0 [pinctrl-bcm2835] (54 lines)
|
|
gpiochip1 [raspberrypi-exp-gpio] (8 lines)
|
|
|
|
$ gpioinfo
|
|
gpiochip0 - 54 lines:
|
|
line 0: unnamed unused input active-high
|
|
line 1: unnamed unused input active-high
|
|
line 2: unnamed unused input active-high
|
|
line 3: unnamed unused input active-high
|
|
line 4: unnamed unused input active-high
|
|
line 5: unnamed unused input active-high
|
|
line 6: unnamed unused input active-high
|
|
line 7: unnamed unused input active-high
|
|
line 8: unnamed unused input active-high
|
|
line 9: unnamed unused input active-high
|
|
line 10: unnamed unused input active-high
|
|
line 11: unnamed unused input active-high
|
|
line 12: unnamed unused input active-high
|
|
line 13: unnamed unused input active-high
|
|
line 14: unnamed unused input active-high
|
|
line 15: unnamed unused input active-high
|
|
line 16: unnamed unused input active-high
|
|
line 17: unnamed unused input active-high
|
|
line 18: unnamed unused input active-high
|
|
line 19: unnamed unused input active-high
|
|
line 20: unnamed "klipper" output active-high [used]
|
|
line 21: unnamed unused input active-high
|
|
line 22: unnamed unused input active-high
|
|
line 23: unnamed unused input active-high
|
|
line 24: unnamed unused input active-high
|
|
line 25: unnamed unused input active-high
|
|
line 26: unnamed unused input active-high
|
|
line 27: unnamed unused input active-high
|
|
line 28: unnamed unused input active-high
|
|
line 29: unnamed "led0" output active-high [used]
|
|
line 30: unnamed unused input active-high
|
|
line 31: unnamed unused input active-high
|
|
line 32: unnamed unused input active-high
|
|
line 33: unnamed unused input active-high
|
|
line 34: unnamed unused input active-high
|
|
line 35: unnamed unused input active-high
|
|
line 36: unnamed unused input active-high
|
|
line 37: unnamed unused input active-high
|
|
line 38: unnamed unused input active-high
|
|
line 39: unnamed unused input active-high
|
|
line 40: unnamed unused input active-high
|
|
line 41: unnamed unused input active-high
|
|
line 42: unnamed unused input active-high
|
|
line 43: unnamed unused input active-high
|
|
line 44: unnamed unused input active-high
|
|
line 45: unnamed unused input active-high
|
|
line 46: unnamed unused input active-high
|
|
line 47: unnamed unused input active-high
|
|
line 48: unnamed unused input active-high
|
|
line 49: unnamed unused input active-high
|
|
line 50: unnamed unused input active-high
|
|
line 51: unnamed unused input active-high
|
|
line 52: unnamed unused input active-high
|
|
line 53: unnamed unused input active-high
|
|
gpiochip1 - 8 lines:
|
|
line 0: unnamed unused input active-high
|
|
line 1: unnamed unused input active-high
|
|
line 2: unnamed "led1" output active-low [used]
|
|
line 3: unnamed unused input active-high
|
|
line 4: unnamed unused input active-high
|
|
line 5: unnamed unused input active-high
|
|
line 6: unnamed unused input active-high
|
|
line 7: unnamed unused input active-high
|
|
```
|
|
|
|
## Optional: Hardware PWM
|
|
|
|
Raspberry Pi's have two PWM channels (PWM0 and PWM1) which are exposed on the header or if not, can be routed to existing gpio pins.
|
|
The Linux mcu daemon uses the pwmchip sysfs interface to control hardware pwm devices on Linux hosts.
|
|
The pwm sysfs interface is not exposed by default on a Raspberry and can be activated by adding a line to ```/boot/config.txt```:
|
|
```
|
|
# Enable pwmchip sysfs interface
|
|
dtoverlay=pwm,pin=12,func=4
|
|
```
|
|
This example enables only PWM0 and routes it to gpio12. If both PWM channels need to be enabled you can use ```pwm-2chan```.
|
|
|
|
The overlay does not expose the pwm line on sysfs on boot and needs to be exported by echo'ing the number of the pwm channel to ```/sys/class/pwm/pwmchip0/export```:
|
|
```
|
|
echo 0 > /sys/class/pwm/pwmchip0/export
|
|
```
|
|
This will create device ```/sys/class/pwm/pwmchip0/pwm0``` in the filesystem.
|
|
The easiest way to do this is by adding this to ```/etc/rc.local``` before the ```exit 0``` line.
|
|
|
|
With the sysfs in place, you can now use either the pwm channel(s) by adding the following piece of configuration to your ```printer.cfg```:
|
|
```
|
|
[output_pin caselight]
|
|
pin: host:pwmchip0/pwm0
|
|
pwm: True
|
|
hardware_pwm: True
|
|
cycle_time: 0.000001
|
|
```
|
|
This will add hardware pwm control to gpio12 on the Pi (because the overlay was configured to route pwm0 to pin=12).
|
|
|
|
PWM0 can be routed to gpio12 and gpio18, PWM1 can be routed to gpio13
|
|
and gpio19:
|
|
|
|
| PWM | gpio PIN | Func |
|
|
| --- | -------- | ---- |
|
|
| 0 | 12 | 4 |
|
|
| 0 | 18 | 2 |
|
|
| 1 | 13 | 4 |
|
|
| 1 | 19 | 2 |
|