- Stock: 4
- Model: SKR 3
Model:
SKR V 1.4 LPC1768 100 MHz
SKR V 1.4 TURBO LPC1769 120 MHz
SKR 2 STM32 180 MHz
SKR 3 STM32 480 MHz
The BIGTREETECH SKR 3 is a 32-bit controller board for custom 3D printers and upgrades requiring five removable driver sockets, two hotend outputs, a heated-bed output, controlled fans, displays, sensors and USB or CAN communication.
The board pictured in HTA3D's current gallery carries an STM32H723VGT6. Very similar SKR 3 boards also exist with an STM32H743. Read the marking on the received MCU and select that exact variant before compiling Marlin or Klipper.
Main features
- Five driver channels: X, Y, Z, E0 and E1; ZMA and ZMB share the same Z driver.
- STEP/DIR, UART and SPI driver modes selected by jumpers.
- 12-24 V DC input.
- Three controlled fans sharing one selected voltage and two always-on input-voltage fan outputs.
- Direct PT1000 support on TH0/TH1 by changing the pull-up from 4.7 kΩ to 1 kΩ with jumpers.
- MicroSD, 24C32 EEPROM, BOOT button, USB, FDCAN, Wi-Fi socket, EXP1/EXP2, TFT, BLTouch, RGB, filament, PS-ON and power-loss interfaces.
Electrical ratings
| Current pictured MCU | STM32H723VGT6; inspect before compiling |
|---|---|
| Input / logic | 12-24 V DC / 3.3 V logic |
| 5 V regulator | 5 A continuous / 6 A instantaneous stated |
| Heated bed | 10 A continuous / 11 A instantaneous |
| HE0 / HE1 | 5.5 A continuous / 6 A instantaneous per output |
| Combined stated limit | HB + HE0 + HE1 + drivers + fans: below 10 A |
| Controlled fans | 1 A continuous / 1.5 A instantaneous per port; one shared selected voltage |
| Board / mounting | 109.67 × 84.30 mm / approximately 101.85 × 76.30 mm |
Per-output ratings do not cancel the combined limit or replace correct wire, terminal, fuse and PSU sizing. High-power beds may require a properly rated external MOSFET or SSR; never switch mains directly from HB.
Drivers, sensors and fans
The sockets support compatible StepStick modules such as UART TMC2208/TMC2209, SPI TMC2130/TMC5160 and STEP/DIR A4988 or DRV8825. Compatibility still depends on voltage, current, pinout and cooling. Configure jumpers only with power disconnected and verify driver orientation. Our TMC2209 V1.3 is a documented UART option.
ZMA and ZMB are wired in parallel to one Z driver; they do not provide independent Z levelling. A separately controlled second Z motor requires another channel.
TH0 and TH1 use a 4.7 kΩ pull-up for 100K NTC or 1 kΩ for PT1000 when the corresponding jumper is fitted. In Marlin a direct PT1000 in this mode uses table 1010. In Klipper use sensor_type: PT1000 and pullup_resistor: 1000. A PT100, thermocouple or amplified sensor requires its own interface and configuration.
All three controlled fans share VIN or the 5/12 V output selected through an optional SKR 3-DC MODE. They cannot simultaneously provide three different voltages.
USB, CAN and firmware
The physical selector changes the USB connector between USB and CAN operation. CAN requires correct wiring, matching bitrate and 120 Ω termination only at both ends of the bus.
Klipper
Klipper's current generic configuration recognises SKR 3 boards with STM32H723 or STM32H743. Enable low-level options, select the MCU actually fitted, a 128 KiB bootloader and a 25 MHz clock. Treat the generic file as a pin reference only; configure the real machine.
Marlin
Use current Marlin, select BOARD_BTT_SKR_3 and the build environment matching the physical MCU. Do not use the old H743 manual setting on an H723 board. Configure drivers, serial ports, sensors, display, endstops and geometry before compiling.
RepRapFirmware
BIGTREETECH provides an SKR 3 RRF package, but it is a historical starting point rather than a universal or necessarily current configuration. Verify MCU, bootloader, pins, Wi-Fi, drivers, sensors and safety settings. Do not mix SKR 3 EZ, SKR 1.4 or other-board files.
A normal microSD update uses firmware.bin, which is renamed to firmware.cur after a successful flash. Use firmware built specifically for SKR 3 and its fitted MCU.
Displays and expansions
EXP1/EXP2, serial TFT, Wi-Fi, probe, RGB, filament, PS-ON and power-loss connectors are provided. Compatibility depends on pinout, voltage, firmware and accessory revision. The BIGTREETECH Mini 12864 V2 has a documented integration, but EXP1/EXP2 orientation and firmware settings still matter.
This is for you if
- you need up to five removable drivers and two hotends;
- you can compile and configure Marlin or Klipper;
- you need direct PT1000, CAN or controlled fans with a shared selectable voltage;
- your project has suitable space, wiring and protection.
This is not for you if
- you need more than five independent channels or two independent Z motors without using E1;
- you want a plug-and-play replacement for a proprietary board;
- you cannot identify H723 versus H743 before compiling;
- your loads exceed an individual or combined electrical rating.
Before power-up
- Check PSU voltage, polarity, fuses and terminals.
- Verify every driver orientation and jumper.
- Select the shared fan voltage and each sensor pull-up.
- Ensure no loose strand can short the board.
- First power up without enabling heaters and verify temperatures, endstops and communication.
- Test motors and outputs one at a time with conservative limits and supervision.
The BIGTREETECH SKR 3 board is supplied. Drivers, SKR 3-DC MODE, display, Wi-Fi module and other expansions are separate unless explicitly included by the selected purchase option.
