Boards Layout — K2 Plus¶
The K2 Plus uses two MCU boards: the main control board and a nozzle MCU board mounted on the toolhead.
Main Control Board¶
Board ID: CR4FN200338C15
MCU chip: GD32F303RET6
Key Pin Assignments¶
| Function | Pin | Notes |
|---|---|---|
| Stepper X step | PB8 |
|
| Stepper X dir | !PB7 |
inverted |
| Stepper X enable | !PA9 |
shared enable |
| Stepper Y step | PB10 |
|
| Stepper Y dir | PB9 |
|
| Stepper Z step | PB6 |
|
| Stepper Z dir | PB5 |
|
| Stepper Z1 step | PB15 |
second Z motor |
| Stepper Z1 dir | PA1 |
|
| Stepper enable (all) | !PA9 |
|
| Endstop X | PB11 |
|
| Endstop Y | PB12 |
|
| Z endstop | probe:z_virtual_endstop |
prtouch_v3 |
| Heated bed heater | PC8 |
|
| Heated bed thermistor | PC4 |
EPCOS 100K |
| Chamber heater (PTC) | PC12 |
heater_generic |
| Chamber thermistor | PC5 |
NTC 100K |
| Chamber cooling fan | PA0 |
temperature_fan, shared pin |
| Chamber PTC fan enable | !PB14 |
heater_fan |
| PTC power enable | PB2 |
output_pin, default 1 |
| Aux fan (fan2) | PB4 + PB3 |
multi_pin |
| LED strip | PB0 + PA12 |
multi_pin, PWM |
| Power output | PC9 |
|
| Z alignment endstops | PA15, PA8 |
z_align module |
| Filament rack sensor | !PA5 |
filament_rack |
| MCU serial (main) | /dev/ttyS2 |
baud 230400 |
| CFS RS-485 serial | /dev/ttyS5 |
baud 230400 |
Nozzle MCU Board¶
Board ID: CR1FN200338C15
MCU chip: GD32F303CBT6
Serial: /dev/ttyS3 baud 230400
Key Pin Assignments¶
| Function | Pin | Notes |
|---|---|---|
| Extruder step | nozzle_mcu:PB5 |
|
| Extruder dir | !nozzle_mcu:PB4 |
inverted |
| Extruder enable | !nozzle_mcu:PB2 |
|
| Hotend heater | nozzle_mcu:PB8 |
|
| Hotend thermistor | nozzle_mcu:PA0 |
custom thermistor |
| Hotend fan (heatsink) | nozzle_mcu:PB7 + PB1 |
multi_pin heater_fan |
| Part cooling fan enable | nozzle_mcu:PB6 |
fan0_en gate |
| Part cooling fan (fan0) | !nozzle_mcu:PB15 |
PWM |
| Extruder fan output | nozzle_mcu:PB1 |
|
| Filament sensor | ^!nozzle_mcu:PA11 |
filament_switch_sensor |
| CFS cut switch | !nozzle_mcu:PB9 |
box switch_pin |
| LIS2DW CS | nozzle_mcu:PA4 |
SPI accelerometer |
| LIS2DW SCLK | nozzle_mcu:PA5 |
|
| LIS2DW MOSI | nozzle_mcu:PA7 |
|
| LIS2DW MISO | nozzle_mcu:PA6 |
|
| prtouch_v3 pressure CS | nozzle_mcu:PB13, nozzle_mcu:PB14 |
strain gauge |
| prtouch_v3 step swap | !PC7 |
main board |
| prtouch_v3 pres swap | nozzle_mcu:PA15 |
Host MCU (Raspberry Pi style)¶
The K2 Plus runs a secondary Linux host MCU for accelerometer data collection.
Serial Port Map¶
| Device | Purpose |
|---|---|
/dev/ttyS2 |
Main MCU (GD32F303RET6) |
/dev/ttyS3 |
Nozzle MCU (GD32F303CBT6) |
/dev/ttyS5 |
CFS RS-485 bus |
Duplicate pin override
The K2 Plus printer.cfg requires a large [duplicate_pin_override] section because several pins are shared between multiple Klipper objects (e.g. PA0 is used by both temperature_fan chamber_fan and output_pin fan2). Do not remove this section or Klipper will refuse to start.