This guide will help you successfully connect and configure your BTT TFT35 SPI V2.1 touch screen with the BTT Manta M5P. We’ll go over the hardware setup, cabling, and software configuration, including calibration tips to avoid ghost touches.

• 🖥️ Integration of BTT TFT35 SPI V2.1 with BTT Manta M5P
  • 🔧 Materials Needed
  • 🛠️ Step 1: Hardware Installation
  • 🔌 Step 2: Cable Length and Ghost Touch Issues
  • 📁 Step 3: Installing KlipperScreen
  • ⚙️ Step 4: Screen Calibration
  • 📚 References

1. BTT TFT35 SPI V2.1 Touch Screen – This is the touch screen we will be using.
2. BTT Manta M5P Board – Your mainboard.
3. 600mm SPI Cable – I recommend using a 600mm cable to avoid ghost touch issues due to interference.
4. Screwdriver, Wires, and Connectors – Standard tools for wiring and connection.

1. Mount the TFT35 Screen: Securely mount the TFT35 SPI V2.1 screen to your printer’s frame.
2. Wiring: Connect the screen to the BTT Manta M5P using the SPI Screen ports on both the screen and the board.
   • Use a 600mm SPI cable to reduce the risk of interference (see the note below for more details on cable length).

When using a longer SPI cable (over 600mm), some users have reported ghost touch issues, which are caused by signal interference. To avoid this problem, it's best to stick to a 600mm cable. If you need one, here is a recommended source:

• 600mm SPI Cable: eBay Link

This should fix most interference issues.

Once the hardware is set up and the screen is calibrated, we need to configure it in Klipper. KIAUH (Klipper Installation and Update Helper) makes it easy to install and configure KlipperScreen.

1. SSH into your CB1: Open a terminal and connect to your CB1 using SSH.
2. Install KlipperScreen:
   • Run the following command to start KIAUH:

   ./kiauh/kiauh.sh

   • In the main menu, type 1 to open the Install Menu, and type 5 to install KlipperScreen.
   • The tool will automate the process. Once completed, you'll see a success message.
3. Restart Klipper: After installation, restart Klipper, and you should see the TFT35 screen interface.

To improve the touch accuracy and avoid any ghost touches, it's important to calibrate your screen. Follow this official tutorial from BTT for calibrating your TFT35 SPI screen:

1. login into your CB1 via SSH
2. Install xinput_calibrator

sudo apt update
sudo apt install xinput-calibrator

3. Query the ID of the touchscreen, The name of TFT35_SPI is ns2009 or TSC2007, as shown in the figure bellow the id is 6

DISPLAY=:0 xinput_calibrator --list

4. Start calibration, Click on the center of the cross that appears one by one on the screen. Replace the id with the actual id found in the previous step. Record the parameters of click 0 X, click 0 Y, click 3 X, and click 3 Y, which are required for conversion.

DISPLAY=:0 xinput_calibrator -v --device <id>

5. !!! WARNING: The parameter of xinput_calibrator cannot be directly used for libinput and needs to be converted. Please refer to here for details:
6. Create conversion script:

sudo nano libinput_calibrator.sh

7. Copy and paste the following content:

#!/bin/bash

#according to https://wiki.archlinux.org/title/Talk:Calibrating_Touchscreen#Libinput%5Fbreaks%5Fxinput%5Fcalibrator

screen_width=$1
screen_height=$2
click_0_X=$3
click_0_Y=$4
click_3_X=$5
click_3_Y=$6

re='^[0-9]+$'
if ! [[ $screen_width =~ $re ]] ; then
  echo "error: screen_width=\"$screen_width\" Not a number" >&2; exit 1
fi
if ! [[ $screen_height =~ $re ]] ; then
  echo "error: screen_height=\"$screen_height\" Not a number" >&2; exit 1
fi
if ! [[ $click_0_X =~ $re ]] ; then
  echo "error: click_0_X=\"$click_0_X\" Not a number" >&2; exit 1
fi
if ! [[ $click_0_Y =~ $re ]] ; then
  echo "error: click_0_Y=\"$click_0_Y\" Not a number" >&2; exit 1
fi
if ! [[ $click_3_X =~ $re ]] ; then
  echo "error: click_3_X=\"$click_3_X\" Not a number" >&2; exit 1
fi
if ! [[ $click_3_Y =~ $re ]] ; then
  echo "error: click_3_Y=\"$click_3_Y\" Not a number" >&2; exit 1
fi

#a = (screen_width * 6 / 8) / (click_3_X - click_0_X)
#c = ((screen_width / 8) - (a * click_0_X)) / screen_width
#e = (screen_height * 6 / 8) / (click_3_Y - click_0_Y)
#f = ((screen_height / 8) - (e * click_0_Y)) / screen_height

a=$(awk "BEGIN { printf(\"%.6f\", ($screen_width * 6 / 8) / ($click_3_X - $click_0_X))}")
c=$(awk "BEGIN { printf(\"%.6f\", (($screen_width / 8) - ($a * $click_0_X)) / $screen_width)}")
e=$(awk "BEGIN { printf(\"%.6f\", ($screen_height * 6 / 8) / ($click_3_Y - $click_0_Y))}")
f=$(awk "BEGIN { printf(\"%.6f\", (($screen_height / 8) - ($e * $click_0_Y)) / $screen_height)}")

CONFIG_OPTION="Option \"CalibrationMatrix\" "
CONFIG_LINE="\"$a 0.000000 $c 0.000000 $e $f 0.000000 0.000000 1.000000\""

echo "${CONFIG_OPTION}${CONFIG_LINE}"
echo ""

CONFIG_OPTION="Option \"CalibrationMatrix\" "
CONFIG="/usr/share/X11/xorg.conf.d/40-libinput.conf"
INPUT_CLASS="Identifier \"libinput touchscreen catchall\""
if [ -e "${CONFIG}" ]; then
    ks_restart=0
    grep -e "^\        ${CONFIG_OPTION}${CONFIG_LINE}" ${CONFIG} > /dev/null
    STATUS=$?
    if [ $STATUS -eq 1 ]; then
        sudo sed -i "/${CONFIG_OPTION}/d" ${CONFIG}
        sudo sed -i "/${INPUT_CLASS}/a\        ${CONFIG_OPTION}${CONFIG_LINE}" ${CONFIG}
        echo "Written to file:"
        echo "    ${CONFIG}"
        echo ""
        ks_restart=1
    fi

    # restart KlipperScreen
    if [ ${ks_restart} -eq 1 ];then
        sudo service KlipperScreen restart
    fi

    echo "run:"
    echo "    DISPLAY=:0 xinput list-props <device>"
    echo "to check if the calibration parameters are effective"
    echo ""
fi

8. Add executable permissions

sudo chmod +x libinput_calibrator.sh

9. Run the script with previous values in argument (got on point 4):

sudo ./libinput_calibrator.sh <screen width> <screen height> <click_0 X> <click_0 Y> <click_3 X> <click_3 Y>

Replace with following values: <screen width>: Screen horizontal resolution, TFT35 SPI is 480 <screen height>: Screen vertical resolution, TFT35 SPI is 320 <click_0 X>: The X position of click 0 during the previous step calibration <click_0 Y>: The Y position of click 0 during the previous step calibration <click_3 X>: The X position of click 3 during the previous step calibration <click_3 Y>: The Y position of click 3 during the previous step calibration

for example:

sudo ./libinput_calibrator.sh 480 320 61 35 417 281

1. BTT TFT35 SPI V2.1 Documentation
2. BTT Manta M5P Documentation
3. 600mm SPI Cable on eBay
4. BTT Screen Calibration Guide
5. KlipperScreen Installation Guide

Feel free to ask any questions or report issues in the MakerFR forum. Happy printing with your new touchscreen setup! 😊