How to Use SKR V1.4: Examples, Pinouts, and Specs

The SKR V1.4, manufactured by BTT (BigTreeTech) with part ID 001, is a powerful 32-bit control board designed for 3D printers. It is based on the ARM Cortex-M3 processor, offering enhanced performance and flexibility compared to traditional 8-bit boards. The SKR V1.4 supports a wide range of stepper motor drivers, multiple connectivity options, and is compatible with popular open-source firmware like Marlin, making it a versatile choice for custom 3D printer builds and upgrades.

• Custom 3D printer builds
• Upgrading existing 3D printers for better performance
• CNC machines and laser engravers
• Robotics projects requiring precise motor control

• Processor: ARM Cortex-M3 (LPC1768, 32-bit)
• Input Voltage: 12V–24V DC
• Stepper Driver Support: Supports TMC, A4988, DRV8825, and other stepper drivers
• Connectivity:
  • USB Type-B for firmware upload and communication
  • SD card slot for offline printing
  • UART, SPI, and I2C interfaces
• Firmware Compatibility: Marlin, Smoothieware
• Number of Stepper Motor Ports: 5 (X, Y, Z, E0, E1)
• Heated Bed Output: 1 channel
• Fan Outputs: 3 controllable fan ports
• Thermistor Inputs: 3 (for hotend, heated bed, and additional sensors)
• Expansion Ports: BLTouch, filament runout sensor, RGB LED, and more

1. Power Supply: Connect a 12V–24V DC power supply to the VIN and GND terminals. Ensure the power supply can handle the current requirements of your 3D printer.
2. Stepper Drivers: Insert compatible stepper drivers (e.g., TMC2208, A4988) into the X, Y, Z, E0, and E1 sockets. Ensure the drivers are oriented correctly.
3. Motors and Sensors: Connect stepper motors, thermistors, and endstops to their respective ports.
4. Heaters and Fans: Attach the hotend heater, heated bed, and fans to the HE0, BED, and FAN ports.
5. Firmware: Flash the board with compatible firmware (e.g., Marlin) using the USB port or SD card. Configure the firmware to match your hardware setup.
6. LCD/Touchscreen: Connect an LCD or touchscreen display to the EXP1 and EXP2 ports if required.
7. Additional Features: Attach optional components like a BLTouch sensor or filament runout sensor to their dedicated ports.

• Stepper Driver Configuration: Set the correct microstepping and current limits on your stepper drivers before installation.
• Cooling: Ensure adequate cooling for the stepper drivers and the board to prevent overheating.
• Firmware Configuration: Customize the firmware (e.g., Marlin) to match your printer's hardware, including stepper motor steps/mm, thermistor types, and endstop logic.
• Wiring: Double-check all connections to avoid short circuits or incorrect wiring.

Below is an example of configuring the SKR V1.4 for use with an Arduino IDE-compatible Marlin firmware:

// Example Marlin configuration for SKR V1.4
// Ensure you select the correct board in the Marlin configuration file

#define MOTHERBOARD BOARD_BTT_SKR_V1_4
#define SERIAL_PORT -1  // Use USB for communication
#define SERIAL_PORT_2 0 // Optional second serial port

// Define stepper motor settings
#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 500 } // X, Y, Z, E
#define DEFAULT_MAX_FEEDRATE          { 300, 300, 5, 25 }  // mm/s
#define DEFAULT_MAX_ACCELERATION      { 3000, 3000, 100, 1000 }

// Define thermistor types
#define TEMP_SENSOR_0 1  // Hotend thermistor
#define TEMP_SENSOR_BED 1 // Heated bed thermistor

// Enable BLTouch for auto bed leveling
#define BLTOUCH
#define AUTO_BED_LEVELING_BILINEAR
#define Z_SAFE_HOMING

1. Board Not Powering On:

   • Ensure the power supply is connected correctly and providing the correct voltage (12V–24V).
   • Check for loose or damaged wires.

2. Stepper Motors Not Moving:

   • Verify the stepper drivers are installed correctly and configured for the correct current.
   • Check the firmware configuration for motor settings.

3. Temperature Readings Incorrect:

   • Ensure the thermistors are connected to the correct ports (TH0, TH1, THB).
   • Verify the thermistor type is correctly defined in the firmware.

4. USB Connection Not Recognized:

   • Install the correct USB drivers for the SKR V1.4.
   • Try a different USB cable or port.

5. Firmware Not Flashing:

   • Ensure the firmware file is named correctly (e.g., firmware.bin) and placed on the SD card.
   • Use a freshly formatted SD card (FAT32 format).

• Can I use the SKR V1.4 with TMC2209 drivers? Yes, the SKR V1.4 supports TMC2209 drivers. Ensure you configure the firmware and jumper settings correctly.

• What firmware is recommended for the SKR V1.4? Marlin is the most commonly used firmware, but Smoothieware is also supported.

• Does the SKR V1.4 support dual Z-axis motors? Yes, you can connect dual Z-axis motors using the Z and E1 stepper driver ports.

• How do I update the firmware? Place the compiled firmware file (firmware.bin) on an SD card, insert it into the board, and power it on. The board will automatically flash the firmware.

• Is the SKR V1.4 compatible with a Raspberry Pi for OctoPrint? Yes, you can connect the SKR V1.4 to a Raspberry Pi via USB for use with OctoPrint.