Toolhead pinout & SWD header#
Transcribed from Sovol’s official pin definition (Motherboard/Extra_Pin_definition.pdf in Sovol3d/SOVOL-ZERO) — see that PDF for the full labelled board image. The toolhead MCU is an STM32F103 (extruder_mcu), board silk MINI-ZJB-V1.0.
Connectors#
| Connector | Pins (as silk-screened) |
|---|---|
| Cooling fan | 24V · PWM PA6 · FG PA1 |
| Fan (top) | 24V · PWM PA7 · FG PA2 |
| Model fan | 24V · PWM PB0 · FG PA3 |
| Nozzle thermistor | PA5 · GND |
| Heating block | GND · 24V · PB1 · GND · PA4 |
| Heater | 24V · MC_HEATER PB7 |
| 24 V supply | GND · 24V |
| Extruder motor | DIR PA9 · STEP PA8 · EN PA11 · UART PA12 |
| X-axis limit | PA10 · GND · 5V |
| Limit / sensor | 5V · GND · PC15 · PC14 |
| Eddy current sensor | 5V3 · GND · PB10 (SCL) · PB11 (SDA) |
| Mainboard comm (CAN) | CANL · GND · CANH (CAN_R PB8 · CAN_T PB9) |
SWD header (silk 5V3 IO CK G) | 5V3 = 3.3 V · IO = SWDIO (PA13) · CK = SWCLK (PA14) · G = GND |
The eddy sensor connector exposes PB10/PB11. On mainline Klipper drive the LDC1612 over software I2C on those pins, not hardware i2c2 — see the Klipper config page.
The SWD header is what you flash once to bootstrap the toolhead. Wiring and the openocd procedure are on the flashing page.
This toolhead is shared with the SV08 Max#
The Zero and the SV08 Max carry the same toolhead module — identical part numbers in the CAD BOM, pin-for-pin factory configs, the same Katapult boot-UUID (61755fe321ac), and a byte-identical pin-definition PDF (Extra_Pin_definition.pdf, md5 b187deb9362b339f55287591f3d510f1 in both official repos). Same board (MINI-ZJB-V1.0), same STM32F103, same eddy probe (LDC1612), same LIS2DW accelerometer.
The Max differs only in how the head is populated and mounted, not in the board:
| Zero | SV08 Max | |
|---|---|---|
| Part cooling | 1 blower (5020, fan0 on PB0) | 2 blowers: 5020 PB0 + 3010 fan1 on PA7 |
Hotend max_temp | 355 | 310 (firmware cap) |
| X carriage / mount | Zero sled | larger-machine adapter |
The key detail: PA7 (“Fan top”) is on the Zero’s board but left unpopulated. The Max hangs a second fan on it. That’s why this pinout page is a component, not a Zero-only fact — a second model reuses it verbatim, and the only config delta is adding or dropping fan1 on PA7.
Not shared: the mainboard and its device tree. Zero (MB_JC_XL_500, 1×Z) and Max (MB_JC_XZ_500, 4×Z quad-gantry, AC bed, feed port) are different PCBs of the same H616 + STM32H750 platform, with different DTS/dtb. Mainboards are not interchangeable as-is.