The BIGTREETECH CB1 uses a custom IO pinout for the pins which consists of PA, PB….PG and a number. To calculate a GPIO Number, you need to use the following formula:

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[(PG - PA)*32] + {Pin Number}
Where PA = 1, PB =2….so PG = 7

So if you want to calculate PG19, then it would be ((7-1)*32) + 19 = 211 = GPIO211. Potentially also this lookup table  might help.

The pins of the 40-pin connector are listed here already - maybe that helps to quickly get the right numbers ;-)

References

• https://github.com/So6Rallye/BTT-Pi/blob/018930134b72f43b6b4b242ffafca145bdffbc87/BIGTREETECH%20Pi%20V1.2%20-%20Board%20Fan%20Pin%20Configuration 

Solution

There are different solutions for this but the following one worked the best for me:

First remove NTP:

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sudo apt remove ntp

and install the systemd-native timesync service:

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sudo apt install systemd-timesyncd

This should automatically install the service and start it. To make sure, you can check that systemd-timesyncd.service is active (running):

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systemctl status systemd-timesyncd

And when using:

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timedatectl status

you should see something like:

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System clock synchronized: yes
              NTP service: active

References

• https://askubuntu.com/a/1373363 

For the inner PCB and other accessories, i went on aliexpress and found the components immediately for sale* - just make sure to choose the version for the 1.5 orbiter.

One of the changes to the original design that i found very useful was the model  to replace the lightguide by one with an M6 adapter to directly connect the PTFE tubes.

For the klipper configuration of the sensor it is best to look at the page of the author  - he has described everything over there.

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[force_move]
enable_force_move: True

but that didn’t help until I manually set a kinematic position through the console:

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SET_KINEMATIC_POSITION X=10 Y=10 Z=10

Which is as per documentation  perfectly correct. Nevertheless I wanted to move without any previous checks or settings. For this I then worked through the documentation  where it actually is described correctly:

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FORCE_MOVE STEPPER=<config_name> DISTANCE=<value> VELOCITY=<value> [ACCEL=<value>]

This command will forcibly move the given stepper the given distance (in mm) at the given constant velocity (in mm/s). If ACCEL is specified and is greater than zero, then the given acceleration (in mm/s^2) will be used; otherwise no acceleration is performed. No boundary checks are performed; no kinematic updates are made; other parallel steppers on an axis will not be moved. Use caution as an incorrect command could cause damage!

Just to reiterate: Use with Caution, it will move without any boundaries etc.

As per the instructions of the installation of Klipper you will have to flash the microcontroller as follows:

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cd ~/klipper/
make menuconfig

During “make menuconfig” select the following settings:

• Enable extra low-level configuration options
• Micro-controller Architecture (STMicroelectronics STM32)
• Processor model (STM32F103)
• Bootloader offset: (28KiB bootloader)
• Communication Interface: (Serial (on USART1 PA10/PA9))

Once you have compiled the firmware using make you can flash it by copying the file out/klipper.bin to a SD card and turning on the printer with the card inserted. The firmware filename must end in “.bin” and must not match the last filename that was flashed.

Resources

• Ender 3 v2 Config from Klipper 
• Klipper Documentation - Installation on the Microcontroller 

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23:29:04 : Erasing memory corresponding to segment 0:
23:29:04 : Not flash Memory : No erase done
23:29:04 : File segment @0x08000000 is not 255-bytes aligned. It will be aligned to @0x07FFFFF8
23:29:04 : Download in Progress:
23:29:05 : Error: failed to download Segment[0]
23:29:05 : Error: failed to download the File

After fiddeling around a bit i finally stumbled across two solutions.

Use Canboot to flash an intermediate firmware

This  failed for me but might a possible path to fix it

Use an older version of the STM32CubeProgrammer

I used version 2.10 of the STM32CubeProgrammer  which solved the case for me at least.

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bed_mesh: min/max points too close together

The reason is relatively simple - it is a bug  in my currently used slicer, OrcaSlicer . It appears to be related to having multiple build plates visible in the slicer - hence it might not happen to you immediately as long as you do not use that feature.

The solution is to either slice only single plates, to switch of “Exclude Objects” or to simply update OrcaSlicer to a version higher or equal to 1.6.2 and you should be able to get rid of this issue.

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Unknown Command "M486"

To me that happened when i switched to Superslicer .

Thankfully it is easy to solve:

• Open Superslicer
• Open your Print Settings
• Search for “Label Objects” (should be in “Output Options”)
• Uncheck the tickbox

That solves it ;)