- Stock: Out of Stock
- Model: SKR PRO V1.2
The BIGTREETECH SKR Pro V1.2 is a 32-bit controller board for custom 3D printers and electronics upgrades requiring six independent motor channels, replaceable drivers and a wide range of connections. It uses a 168 MHz STM32F407ZGT6 ARM Cortex-M4, operates from 12 or 24 V DC and supports STEP/DIR, UART or SPI drivers through its jumper configuration.
It provides outputs for a heated bed, three heaters and three fans, four 100K NTC thermistor inputs, microSD, USB, display connections, serial Wi-Fi and several expansion interfaces. It is a flexible platform, but not a plug-and-play replacement: mounting, wiring, connectors, drivers, power distribution and firmware must all be adapted to the actual machine.
Main features
- STM32F407ZGT6 microcontroller: 168 MHz 32-bit ARM Cortex-M4 core.
- 12 to 24 V DC input.
- Six replaceable driver sockets: X, Y, Z, E0, E1 and E2.
- Three control modes: STEP/DIR, UART and SPI, depending on driver and jumper position.
- Seven motor connectors: X, Y, Z1, Z2, E0, E1 and E2; Z1 and Z2 share the Z channel.
- Four heater outputs: bed, HE0, HE1 and HE2.
- Four temperature inputs for 100K NTC thermistors.
- Three firmware-controlled fan outputs.
- USB-B and microSD for communication, printing and firmware updates.
- EXP1/EXP2, serial TFT, ESP-01S, BLTouch, filament sensor, shutdown and power-loss connections, depending on accessory and firmware.
- 147 × 95 mm PCB with 138 × 86.5 mm mounting centres.
Technical specifications
| Feature | Value |
|---|---|
| Manufacturer and revision | BIGTREETECH SKR Pro V1.2 |
| Microcontroller | STM32F407ZGT6, 168 MHz ARM Cortex-M4 |
| Power input | 12–24 V DC |
| Drivers | 6 replaceable sockets: X, Y, Z, E0, E1 and E2 |
| Driver modes | STEP/DIR, UART or SPI through jumpers |
| Motor connectors | 7: X, Y, shared Z1/Z2, E0, E1 and E2 |
| Heaters | Bed + HE0 + HE1 + HE2 |
| Temperature inputs | T0, T1, T2 and T3 for 100K NTC sensors |
| Fans | 3 controlled outputs |
| Storage | microSD |
| Communication | USB-B and serial/expansion ports |
| Displays | BIGTREETECH serial TFT, LCD2004 and LCD12864 subject to wiring and firmware |
| Expansion | ESP-01S, BLTouch, filament sensor, PWR-DET, PS-ON, PWM, ADC, UART, I2C and SPI |
| Dimensions | 147 × 95 mm; 138 × 86.5 mm mounting centres |
| Recommended firmware | Marlin 2 or Klipper |
Power distribution
The SKR Pro V1.2 divides its input across three terminal pairs: motor power, main-board power and heated-bed power. This arrangement distributes current across multiple wires and terminals. The manufacturer's wiring shows all three inputs connected to the same power supply, so they must not be assumed to support mixed voltages.
A logic-power jumper selects board-supply or USB power. Set it with everything disconnected; it does not select the voltage for motors, heaters or fans.
Replaceable STEP/DIR, UART and SPI drivers
The six sockets accept compatible StepStick-footprint modules such as A4988, DRV8825 and several TMC drivers, provided that orientation, pinout, logic level, motor voltage and control mode all match. A shared physical footprint alone does not establish electrical compatibility.
UART or SPI operation requires both the correct channel jumpers and matching firmware configuration. SPI drivers share the spi3a bus; the board's SPI expansion uses some of the same signals and cannot be used simultaneously when those pins are already assigned to SPI drivers.
The BIGTREETECH TMC2209 V1.3 is a current UART option in our catalogue. Each driver is sold separately and its current must be configured for the actual motor, cooling and load.
DIAG pins on StallGuard-capable drivers may share the mechanical endstop signal. If a physical switch is retained, verify the actual module and isolate DIAG with an appropriate reversible method. Do not automatically cut a pin or copy sensitivity from a different machine.
Printer and accessory compatibility
The board can control Cartesian, CoreXY, delta/Kossel and other custom machines when six independent channels are sufficient. It can also be adapted to commercial printers, but it is not a direct replacement for an Ender, CR-10, Prusa, Anycubic, Artillery, Voron or another model merely because both use NEMA 17 motors and a 24 V supply.
Compatibility requires checking or adapting:
- The number of independent motors, extruders, heaters, fans and sensors.
- Power-supply, bed, heater-cartridge and fan voltage and power.
- Connectors, polarity, coil order, endstops and probe pinout.
- Board dimensions, mounting centres, insulation and enclosure cooling.
- Display, EXP/TFT wiring and firmware.
- CAN or other required interfaces: the SKR Pro V1.2 has no documented native CAN interface.
The BIGTREETECH TFT35 V3.0 can operate through the serial TFT connection and, with suitable wiring and firmware, through EXP1/EXP2 in LCD mode. Always verify orientation and pinout before applying power.
If a project only needs five drivers and a newer generation is preferred, consider the BIGTREETECH SKR 3. For machines requiring eight sockets and additional outputs, the BIGTREETECH Octopus Pro H723 is a more natural candidate. Select by system requirements rather than processor speed alone.
It is for you if
- You need up to six independently controlled motors.
- You want replaceable drivers and a choice of STEP/DIR, UART or SPI.
- Your machine uses up to three extruders and three hotends.
- You will adapt wiring, enclosure, cooling and firmware to a custom project.
- You want a board supported by Marlin 2 or Klipper with many expansion connections.
It is not for you if
- You need a drop-in replacement retaining the original screws, connectors and firmware.
- You require more than six independent drivers or integrated CAN.
- You want integrated drivers and do not wish to configure jumpers or motor current.
- Your bed exceeds the manufacturer's direct-output limit and you do not want an external power stage.
- Your project depends on USB host or another function not verified with your selected firmware.
Marlin 2 configuration
Current Marlin versions include a board definition specifically for this revision. The base selection in Configuration.h is:
#define MOTHERBOARD BOARD_BTT_SKR_PRO_V1_2
// Example: declare every driver that is actually installed
#define X_DRIVER_TYPE TMC2209
#define Y_DRIVER_TYPE TMC2209
#define Z_DRIVER_TYPE TMC2209
#define E0_DRIVER_TYPE TMC2209
// #define E1_DRIVER_TYPE TMC2209
// #define E2_DRIVER_TYPE TMC2209This block only identifies the board and driver types. Geometry, direction, steps or movement per revolution, current, endstops, temperature sensors, heaters, fans, display, probe and thermal protection must still be configured. Do not use firmware built for another printer just because it also has an SKR Pro.
After compiling, copy firmware.bin to a microSD card, insert it with the board powered off and switch on. Verify that the update completed correctly before removing the card. Keep thermal protection enabled and test temperatures, endstops and motion separately.
Klipper configuration
Klipper maintains an official generic configuration for the SKR Pro. Build settings are:
- STM32F407 microcontroller.
- 32 KiB bootloader.
- microSD update: after
make, copyout/klipper.binasfirmware.bin.
The usual make flash procedure does not work on this board. After flashing, obtain the actual identifier from /dev/serial/by-id/ and use it in the [mcu] section.
Main pin map from the official configuration:
| Channel | STEP | DIR | ENABLE | UART | SPI CS |
|---|---|---|---|---|---|
| X | PE9 | PF1 | !PF2 | PC13 | PA15 |
| Y | PE11 | PE8 | !PD7 | PE3 | PB8 |
| Z | PE13 | PC2 | !PC0 | PE1 | PB9 |
| E0 | PE14 | PA0 | !PC3 | PD4 | PB3 |
| E1 | PD15 | PE7 | !PA3 | PD1 | PG15 |
| E2 | PD13 | PG9 | !PF0 | PD6 | PG12 |
For SPI drivers, Klipper uses the spi3a bus. Main outputs are bed PD12, HE0 PB1, HE1 PD14, HE2 PB0, and fans PC8, PE5 and PE6. T0–T3 temperature inputs are PF3, PF4, PF5 and PF6.
Installation and first start-up
- Disconnect both power supply and USB before touching drivers, jumpers or wiring.
- Confirm the V1.2 revision and check every connection against the official pinout.
- Mount the board on insulating spacers, away from metal contact, with airflow over both board and drivers.
- Set each driver's jumpers before insertion and verify orientation.
- Identify both coils on each motor; never connect or disconnect motors while powered.
- Check polarity and cable size for all three power-input pairs, tighten terminals and add suitable protection.
- With heaters disconnected, verify communication, cold temperature readings, endstops and motor direction.
- Test each heater together with its corresponding sensor at a low temperature under supervision.
- Tune PID or the selected control method only after confirming sensors and outputs are correct.
- Monitor driver, terminal, fuse, MOSFET, wire and connector temperature during the first prints.
Package contents
- 1 BIGTREETECH SKR Pro V1.2 board.
- 1 USB cable.
- Power leads shown in the photographs.
- 1 microSD card.
Drivers, heatsinks, display, Wi-Fi module, power supply, sensors and other accessories are sold separately.
Technical documentation
For pinout, jumpers and wiring, see BIGTREETECH's official SKR Pro V1.2 repository. Klipper also maintains an official generic configuration and pin map; its machine parameters are examples and must be adapted.
