Klipper on the BIQU BX V3

biqu_bx_klipper_v3.md

Klipper on the BIQU BX V3

NOTE: If you have a V2 board/screen(HDMI),click here

First, a few requirements:

1. You need Klipper setup on your Raspberry PI ( borad that support DSI) with your favorite control interface (Octoprint, Fluidd, Mainsail, etc..).
   • I recommend installing official Raspberry Pi OS
     • Download this file https://downloads.raspberrypi.com/raspios_armhf/images/raspios_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf.img.xz and use the Raspberry Pi Installer and select custom image.
2. Install the Drivers for V3 screen https://github.com/bigtreetech/BIQU-BX/tree/master/Firmware/RPi-Linux-RPi-7inch-DSI
3. You need your favorite Touchscreen UI installed (unless you just want to run headless).
   • Use this to install all you need https://github.com/dw-0/kiauh
     • If you have a issue with the screen is black, press the smal button under the turn knob
4. You MUST have removed the Z endstop physical switch. Not disconnected, but completely removed.

NOTE: CAN will not work on this board due to a hardware mis-configuration
NOTE: I2C is not quite working yet!

Ok, so let's get started.

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Klipper firmware configuration

When configuring the klipper firmware to run on the BTT SKR SE BX board, there are a couple things to know about.

1. Use the main klipper branch.
2. In order for the toucscreen to work, you will need to set GPIO pins PB5 and PE5 to an initial state during the config
3. Use the config/printer-biqu-bx-2021.cfg file for your intial printer.cfg
4. Once you are setup, you will need to calibrate your sensorless homing: https://www.klipper3d.org/TMC_Drivers.html?h=sensorless+ho#sensorless-homing

A note on connection methods:

There are 4 different connections you can make from the Raspberry Pi to the mainboard, 2 Serial and 2 USB.

• Serial (on UART4 PA0/PA1) <--- For v3 board/screen you need to use this

To use serial connections, you have to enable the serial port on the raspberry pi and compile the correct serial port for the BX mainboard. Once you have the serial port enabled on the raspberry pi, it will show up as /dev/ttyAMAx, with x being the port number.

Once you have it setup, your printer.cfg should then contain the following under the MCU section: serial: /dev/ttyAMAx, substituting the x for your port number.

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HDMI configuration

As v3 uses DSI you don't need any HDMI settings

Drivers for V3 screen

• Go to and follow the guide https://github.com/bigtreetech/BIQU-BX/tree/master/Firmware/RPi-Linux-RPi-7inch-DSI

Config.txt

Example on /boot/config.txt

Make sure this are in the config.txt file, some wil be added by the drivers installation skript.
[all]
dtparam=i2c_vc=on
dtparam=i2c_arm=on
enable_uart=1
dtoverlay=disable-bt
dtoverlay=vc4-kms-dsi-btt-bxv3-7inch
disable_splash=1

Slicer configuration

For your slicer, you need to call the PRINT_START macro instead of any preliminary gcode. The NOZZLE and BED temps get passed in as arguments. Some examples for the more popular slicers:

• Cura: PRINT_START BED={material_bed_temperature_layer_0} NOZZLE={material_print_temperature_layer_0}
• PrusaSlicer: PRINT_START NOZZLE=[first_layer_temperature] BED=[bed_temperature]
• Ideamaker: PRINT_START NOZZLE={temperature_heatbed} BED={temperature_extruder1}
• Simplify3D: PRINT_START NOZZLE=[extruder0_temperature] BED=[bed0_temperature]
• Kiri:Moto: PRINT_START NOZZLE={temp} BED={bed_temp}

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Klipper Functionality

Here are some notes on how I have Klipper setup and working quite well for my machine.

Touchscreen Sleep

The Touchscreen will go dark when the printer idle timeout occurs. This happens when there is not a print job in action and currently set for 5 minutes. Pressing the Menu Knob on the display will wake up the Touchscreen.

LEDS

The Neopixels are setup and will cycle through colors on bootup. I have the idle timeout set to shut off the LEDS when the printer is inactive. The LEDs automatically come on when a print is started or when the LCD is wakened.

Homing Routine

I have programmed a reliable homing routine that works well for me, however you can adjust or setup your own to taste. My routine will do the following:

1. Raise the Z axis
2. Home the X axis
3. Home the Y axis
4. Move the probe to the center of the bed (different than the nozzle at center)
5. Home the Z with the probe.

• When starting a print, additionally:

6. After the bed reaches temp, the printer waits for 90 seconds with the probe close to the bed to warm up the probe.
7. Steps 1-5 are repeated with a warm probe
8. Move to the origin to start the print.

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details
# impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

# Automatically load overlays for detected cameras
camera_auto_detect=1

# Automatically load overlays for detected DSI displays
#display_auto_detect=1

# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d
max_framebuffers=2

# Disable compensation for displays with overscan
disable_overscan=1

[cm4]
# Enable host mode on the 2711 built-in XHCI USB controller.
# This line should be removed if the legacy DWC2 controller is required
# (e.g. for USB device mode) or if USB support is not required.
otg_mode=1

[all]

[pi4]
# Run as fast as firmware / board allows
arm_boost=1

[all]
dtparam=i2c_vc=on
dtparam=i2c_arm=on
enable_uart=1
dtoverlay=disable-bt
dtoverlay=vc4-kms-dsi-btt-bxv3-7inch
disable_splash=1

What happens when you run this command ? DISPLAY=:0 xrandr

Mine looks like this Screen 0: minimum 320 x 200, current 1024 x 600, maximum 2048 x 2048 HDMI-1 disconnected primary (normal left inverted right x axis y axis) DSI-1 connected 1024x600+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1024x600 38.40*+

DISPLAY=:0 xrandr
Can't open display :0

I checked the flat cable continuity with a multimeter, board-to-board, and it's ok. Since I have 2 sets of TFT70 and PI I tried the second set with the sane result !

You are sure the printer has klipper? Try to flash it again.
I tried to flash it many times, at start-up it displays firmware update 0%-100% and then rename the firmware.bin into firmware.cur so I suppose it was flaseh correctly.

Hmm, and it's a RPi and not a BTT Pi ? That would explain the screen. But the communication with the MCU should be the same.

the cable is like this on the board

Yes, it's a RPi4 B / 2018, the red wire on the 5V.
Using Octoprint to control the printer flashed with Marlin it used to work, so I guess the connection through the TFT70 is functional

I am wondering if it could be possible to bypass the TFT70 board and connect the PI to the printer using the USB ports ?
I am also considering switching to a Manta board, may be easyer to get working with Klipper ?

I am now able to connect to the MCU using using pin 6-8-10 of the PI and the TFT pins of the SKR-SE-BX-V3.0 (crossing Rx and Tx).
The TFT display is useless (just to confirm that the MCU is flashed correctly).

and configuring serial USART1 PA10/PA9

I am now able to connect to the MCU using using pin 6-8-10 of the PI and the TFT pins of the SKR-SE-BX-V3.0 (crossing Rx and Tx). The TFT display is useless (just to confirm that the MCU is flashed correctly).

Strange that you need to do that.
Well it's not the best screen. I have issue that it's all white until it's "warm"

I had problem connecting to the printer even after following the step described. My settings are the original as varazir adviced. After some research i found that my problem was fixed after removing the section "console=serial0,11520" from '/boot/cmdline.txt' with a text editor.
Now i am able to see the printer using