Pinout

Note

• This page lists the pinout of the FLY-CDY-V3 mainboard after flashing Klipper firmware. Pin numbers are based on the mainboard schematic.
• UART/CS is the driver communication pin: used as UART with TMC2209, or as chip select CS with SPI drivers such as TMC5160. The same pin is multiplexed for both functions.
• EN is the enable pin. In Klipper configuration, it is typically active low (the enable_pin has a ! prefix).
• DIAG is the driver diagnostic signal pin. When using sensorless homing, configure the corresponding diag_pin according to the table below.

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Driver Pins

The FLY-CDY-V3 provides 6 driver ports:

Driver	STEP	DIR	EN	UART/CS	DIAG
DRIVER0	PE5	PC0	PC1	PC15	PC7
DRIVER1	PE4	PC13	PC14	PA8	PC6
DRIVER2	PE3	PB7	PB8	PB6	PD11
DRIVER3	PE2	PD6	PD7	PD5	PD10
DRIVER4	PE1	PD3	PD4	PD1	PB10
DRIVER5	PE0	PA15	PD0	PE9	PB11

Power Off Before Operation

Before starting, completely power off the printer and disconnect the power supply. Do not plug or unplug wiring harnesses, rearrange connector wiring, or touch terminals while the power is on.

DIAG and Sensorless Homing

When using sensorless homing, the driver chip outputs a stall detection signal through the DIAG pin, and Klipper needs to read this signal via the corresponding input port. The correspondence between the DIAG pins and the endstop ports on this mainboard is shown in the "Endstops and Probe" table below.

Once sensorless homing is enabled, the corresponding endstop port is occupied by the DIAG signal, and mechanical or optical endstop switches must not be connected simultaneously.

SPI Bus

SPI drivers such as the TMC5160 use the mainboard's hardware SPI bus. Simply configure spi_bus: spi3 in the configuration; there is no need to separately configure the MOSI/MISO/SCLK pins:

[tmc5160 stepper_x]
spi_bus: spi3
cs_pin: corresponding driver's UART/CS pin

Detailed instructions on software SPI, SPI speed, etc.: SPI Configuration Method

Endstops and Probe

Function	Pin	Corresponding Driver DIAG
Endstop 0 (X-MIN)	PC7	DRIVER0
Endstop 1 (X-MAX)	PC6	DRIVER1
Endstop 2 (Y-MIN)	PD11	DRIVER2
Endstop 3 (Y-MAX)	PD10	DRIVER3
Endstop 4 (Z-MIN)	PB10	DRIVER4
Endstop 5 (Z-MAX)	PB11	DRIVER5
Probe	PC2	-

Heating

Function	Pin
Heated Bed	PB0
Heater 0	PD12
Heater 1	PD13
Heater 2	PD14

Temperature Sensors

Function	Pin
Bed Thermistor	PB1
Thermistor 0	PA3
Thermistor 1	PC4
Thermistor 2	PC5

Supported Thermistor Types

The thermistor ports support NTC thermistors (100K) by default. It is recommended to configure sensor_type as Generic 3950.

List of built-in sensor_type options in Klipper and their applicable scenarios: Thermistor Configuration Method

K-type thermocouples, PT100, etc., require additional signal conversion chips and cannot be connected directly to the thermistor ports.

Fans

Function	Pin
Fan 0	PA0
Fan 1	PA1
Fan 2	PA2

PWM

The FLY-CDY-V3 provides 3 PWM outputs, which can be used for servos, lasers, RGB, etc.:

Pin	Notes
PE6	Servo / BLTouch control
PB9	LASER
PD15	RGB / Neopixel

BL-Touch

Function	Pin
Servo Signal	PE6
Probe Signal	PC2

RGB

Function	Pin
Neopixel	PD15

Expansion SPI / ADXL345

Function	Pin
CS	PE7
SCK	PA5
MISO	PA6
MOSI	PA7
Spare IO	PE6

Pin Multiplexing

• PE6 is simultaneously routed to the expansion header and the BL-Touch servo signal port. When using it, configure only one of these functions.
• PA5 / PA6 / PA7 appear simultaneously on the expansion SPI and the EXP2 header. Do not configure them for conflicting functions on two different peripherals.
• PA9 / PA10 are simultaneously routed to the UART interface and the EXP1 header. When UART is not in use, they can also be used as general-purpose inputs in Klipper. Common uses include filament runout detection and jam detection.

UART / General Purpose Inputs

Pin	UART Function	Other Common Uses
PA9	TX	General-purpose input, usable for filament runout detection, jam detection, etc.
PA10	RX	General-purpose input, usable for filament runout detection, jam detection, etc.

ST-LINK

Function	Pin
SWDIO	PA13
SWCLK	PA14
RESET	RST

EXP1

EXP Configuration Reminder

• The EXP headers are commonly used for Mini12864 displays or other expansion peripherals.
• If a pin is already occupied by SPI, UART, endstop, fan, or other functions, do not configure it again for an EXP peripheral.

Header Pin	MCU Pin
EXP1_1	NC
EXP1_2	PA9
EXP1_3	PB2
EXP1_4	PA10
EXP1_5	PE15
EXP1_6	PE14
EXP1_7	PA13
EXP1_8	PA14
EXP1_9	GND
EXP1_10	5V

EXP2

Header Pin	MCU Pin
EXP2_1	PA6
EXP2_2	PA5
EXP2_3	PD8
EXP2_4	PA4
EXP2_5	PD9
EXP2_6	PA7
EXP2_7	PE13
EXP2_8	RST
EXP2_9	GND
EXP2_10	NC