BigTreeTech MMB Cubic

The BigTreeTech MMB Cubic is the ideal solution for fitting additional interfaces onto your printer, allowing you to connect more things like, Neopixels, temperature sensors, etc...

Here we will see the addition of Neopixels and a chamber temperature sensor.

Interface Diagram

Prerequisites

BigTreeTech MMB Cubic: Biqu
2 x 18 AWG (minimum) silicone electrical wire to power the BigTreeTech MMB Cubic
1 x USB-C cable
MMB Cubic Mount to print: MMB_Cubic_Mount.stl
4 x M3x8 screws to fix MMB Cubic to mount
Double-sided tape to secure the mount in the lower part of the printer
WS2812B - 5V LED strip (to replace existing LED strips)
1 x NTC 100k Thermistor Temperature Sensor (I use the one from FLSUN V400 because it has the advantage of having a long cable)

Wiring

Note

BigTreeTech MMB Cubic can be powered over USB but I don't recommend this for better performance.

Compiling Firmware

Connect to printer over SSH (see SSH Connection section).
In the SSH command prompt window, enter the following commands (one at a time):
SSH Command Prompt
```
cd ~/klipper/
```
SSH Command Prompt
```
make menuconfig
```
Move on the menu with the ↑ and ↓ keys of your keyboard and validate the selected item with the Enter key and select these settings:
Then on your keyboard press the Q key then Y to save configuration.
Enter the following commands (one at a time) to compile firmware:
SSH Command Prompt
```
make clean
```
SSH Command Prompt
```
make
```
When make is completed, the required klipper.bin firmware will be generated in the home/pi/klipper/out folder.

Flash Firmware

If BigTreeTech MMB Cubic is already connected via USB-C, unplug it.
Hold down the BOOT button and connect BigTreeTech MMB Cubic to printer with a USB-C cable. This allows the chip to enter DFU mode:
In the SSH command prompt window, enter the following command to query the DFU device ID (it should be named Raspberry Pi RP2 Boot):
SSH Command Prompt
```
lsusb
```
Enter the following commands (one at a time) to flash firmware by replacing xxxx:xxxx with the actual device ID obtained in the previous step:
SSH Command Prompt
```
cd ~/klipper/
```
SSH Command Prompt
```
make flash FLASH_DEVICE=xxxx:xxxx
```
Example
SSH Command Prompt
```
make flash FLASH_DEVICE=2e8a:0003
```
After flashing, enter the following command to query the device Serial ID:
SSH Command Prompt
```
ls /dev/serial/by-id/
```
Copy the Serial ID it will be used later for the configuration file.

Note

There is no need to manually press the BOOT button to enter DFU mode for subsequent updates after the first flashing is completed.

To update BigTreeTech MMB Cubic firmware just use this command by replacing xxxxx` by your Serial ID:

SSH Command Prompt

make flash FLASH_DEVICE=/dev/serial/by-id/usb-Klipper_rp2040_xxxxx

Example

SSH Command Prompt

make flash FLASH_DEVICE=/dev/serial/by-id/usb-Klipper_rp2040_5044340310A8901C-if00

Configuration

MMB Cubic can be configured automatically with Easy Installer or with Printer Setup Wizard from KlipperScreen or Web interface (
see Update and Configure Printer section) but if you need to configure it manually follow these steps.

Open config.cfg file:
- On Mainsail Web Interface go to MACHINE tab on the left side.
- On Fluidd Web Interface go to Configuration icon on the left side.

Edit the Configurations section:

config.cfg

#######################################################
# BigTreeTech MMB Cubic Configuration
#######################################################

# If you use BigTreeTech MMB Cubic -> Enable this lines and set the serial
# ------------------------------------------------------------------------

#[mcu MMB_Cubic]
#serial: /dev/serial/by-id/usb-Klipper_rp2040_xxxxx


# If you use Chamber Temperature Sensor with BigTreeTech MMB Cubic -> Enable 'temp-sensor-mmb-cubic.cfg'
# ------------------------------------------------------------------------------------------------------

#[include Configurations/temp-sensor-mmb-cubic.cfg]


# If you use Neopixels with BigTreeTech MMB Cubic -> Disable 'led-stock.cfg' and Enable 'led-mmb-cubic.cfg'
# ---------------------------------------------------------------------------------------------------------

[include Configurations/led-stock.cfg]
#[include Configurations/led-mmb-cubic.cfg]

Edit the serial parameter by replacing xxxxx` with your previously obtained serial ID.

Once done, click on SAVE & RESTART button at the top right to save the file.
Open led-mmb-cubic.cfg file in Configurations folder and edit the chain_count parameter by the number of LEDs your strips contain:
led-mmb-cubic.cfg
```
[neopixel chamber_led]
pin: MMB_Cubic:gpio9
chain_count: 20
color_order: GRB
initial_RED: 1.0
initial_GREEN: 1.0
initial_BLUE: 1.0
```
Once done, click on SAVE & RESTART button at the top right to save the file.
You should see the MMB Cubic MCU connected in the system information:

Mainsail

Fluidd
You can now control Neopixels from screen in Configurations → LED menu:
If you use chamber temperature sensor, you can see the temperature here:

Update MCU firmware

Note

MCUs have limited write cycles. Updating the firmware with each Klipper release could shorten the life of your MCU!

When is it necessary to update MCU firmware?
Every time Klipper mentions to update the MCU at startup, no more.

To update to a future MCU firmware of your MMB Cubic, follow these steps:

Connect to printer over SSH (see SSH Connection section).
In the SSH command prompt window, enter the following command to start Easy Installer:
SSH Command Prompt
```
easy-installer
```
Enter 3 for Extras menu → 3 for Update MMB Cubic MCU firmware → Enter to confirm your choice:
Klipper firmware will be builded and flashed.
When it's done, Turn the printer off and on.

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