STM32H745 Pin Usage (V2 Prime)

See LPC1769 pin usage for Smoothieboard V1 pin assignments.

This page documents all pin assignments for the STM32H745XIHx microcontroller on Smoothieboard V2 Prime.

This comprehensive reference shows how every pin on the STM32H745 is assigned on Smoothieboard V2 Prime (TMC2660 variant). Use this to identify available pins for custom functionality via the Gadgeteer expansion headers.

Pin List

The following table shows all pin assignments on the STM32H745XIHx microcontroller:

STM32 Pin	Smoothie Pin	BGA Position	Assignment	Comment
PA0	PA0	N5	GPIO	General purpose
PA0_C	ADC1_0	N5	Board Temp (T4)	Config: `ADC1_0`, buffered via LMV324
PA1	PA1	N4	ETH_REFCLK	50MHz Ethernet reference clock
PF11	ADC1_1	P5	Thermistor 1 (T1)	Config: `ADC1_1`, buffered via LMV324
PF12	ADC1_2	R7	Thermistor 2 (T2)	Config: `ADC1_2`, buffered via LMV324
PA2	PA2	N3	ETH_MDIO	Ethernet management data I/O
PA3	PA3	U2	Expansion GH	ADC1_CH15 available
PA4	PA4	U3	I2C2_SCL	User I2C bus clock
PA5	PA5	T3	Expansion GH	DAC1_OUT2 available
PA6	PA6	R3	Expansion GH	ADC1_CH3 available
PA7	PA7	R5	ETH_CRSDV	Ethernet carrier sense/data valid
PA8	PA8	E15	Expansion GH	GPIO
PA9	PA9	D15	Expansion GH	GPIO
PA10	PA10	D14	Expansion GI	GPIO
PA11	PA11	E17	USB_DEV_D-	USB device data minus
PA12	PA12	E16	USB_DEV_D+	USB device data plus
PA13	PA13	C15	SWDIO	Debug data (hardcoded)
PA14	PA14	B14	SWCLK	Debug clock (hardcoded)
PA15	PA15	A14	TDI	JTAG data in
PB0	PB0	U5	PROBE	Probe input via comparator
PB1	PB1	T5	I2C2_SDA	User I2C bus data
PB2	PB2	R6	QSPI_SCK	QSPI flash clock
PB3	PB3	C6	SPI1_SCK / SWO	User SPI clock / trace output
PB4	PB4	B7	SPI1_MISO	User SPI data in
PB5	PB5	A5	SPI1_MOSI	User SPI data out
PB6	PB6	B5	QSPI_CS	QSPI flash chip select
PB7	PB7	C5	GPIO	General purpose
PB8	PB8	D5	GPIO	General purpose
PB9	PB9	D4	GPIO	General purpose
PB10	PB10	P11	Expansion GI	GPIO
PB11	PB11	P12	Expansion GI	GPIO
PB12	PB12	T14	Motor B CS	TMC2660 chip select
PB13	PB13	U14	USB_PWR_ON	USB host power control
PB14	PB14	U15	USB_HOST_D+	USB host data plus
PB15	PB15	T15	USB_HOST_D-	USB host data minus
PC0	PC0	L2	SSR1	Solid state relay output 1
PC1	PC1	M2	ETH_MDC	Ethernet management clock
PC2	PC2	M3	Expansion (GH)	ADC1_4 available as `ADC1_4`
PC3	PC3	M4	Expansion (GH)	ADC1_5 available as `ADC1_5`
PC4	PC4	T4	VMOT_SENSE	Motor voltage sense (11:1 divider)
PC5	PC5	U4	VFET_SENSE	MOSFET voltage sense (11:1 divider)
PC6	PC6	F14	Expansion GC	GPIO
PC7	PC7	F13	Expansion GC	GPIO
PC8	PC8	E13	SD_D0	SD card data 0 (hardcoded)
PC9	PC9	E14	SD_D1	SD card data 1 (hardcoded)
PC10	PC10	A13	SD_D2	SD card data 2 (hardcoded)
PC11	PC11	B13	SD_D3	SD card data 3 (hardcoded)
PC12	PC12	C12	SD_CK	SD card clock (hardcoded)
PC13	PC13	E3	GPIO	General purpose
PC14	PC14	C2	XTAL_LSE_IN	32.768kHz crystal in (hardcoded)
PC15	PC15	C1	XTAL_LSE_OUT	32.768kHz crystal out (hardcoded)
PD0	PD0	D13	UART4_RX	Expansion GD UART receive
PD1	PD1	E12	UART4_TX	Expansion GD UART transmit
PD2	PD2	D12	SD_CMD	SD card command (hardcoded)
PD3	PD3	B12	Expansion GD	GPIO
PD4	PD4	A12	Expansion GD	GPIO
PD5	PD5	A11	USART2_TX / Debug TX	Debug UART transmit
PD6	PD6	B11	USART2_RX / Debug RX	Debug UART receive
PD7	PD7	C11	Expansion GD	GPIO
PD8	PD8	U16	USART3_TX	Expansion UART transmit
PD9	PD9	T17	USART3_RX	Expansion UART receive
PD10	PD10	T16	GPIO	General purpose
PD11	PD11	R15	QSPI_IO0	QSPI flash data 0
PD12	PD12	R16	QSPI_IO1	QSPI flash data 1
PD13	PD13	R17	QSPI_IO3	QSPI flash data 3
PD14	PD14	P16	MOTSPI_MOSI	Motor SPI data out (hardcoded)
PD15	PD15	P15	Expansion GC	GPIO
PE0	PE0	C4	Expansion GE	GPIO
PE1	PE1	B4	Expansion GE	GPIO
PE2	PE2	C3	QSPI_IO2	QSPI flash data 2
PE3	PE3	D3	Expansion GE	GPIO
PE4	PE4	D2	MOTSPI_MISO	Motor SPI data in (hardcoded)
PE5	PE5	D1	TIM15_CH1	Expansion GE PWM
PE6	PE6	E5	TIM15_CH2	Expansion GE PWM
PE7	PE7	U9	Expansion GE	GPIO
PE8	PE8	T9	Expansion GE	GPIO
PE9	PE9	P9	TIM1_CH1	Timer 1 channel 1 PWM
PE10	PE10	N9	Motor D Step / BDET	Motor D step, also board detect bit 3
PE11	PE11	P10	TIM1_CH2	Timer 1 channel 2 PWM
PE12	PE12	R10	Motor D Dir / TIM1_CH3	Motor D direction
PE13	PE13	T10	TIM1_CH4	Timer 1 channel 4 PWM (spare)
PE14	PE14	U10	Motor C Step	TMC2660 motor C step
PE15	PE15	R11	Motor C Dir	TMC2660 motor C direction
PF0	PF0	G4	Expansion GF	GPIO
PF1	PF1	G3	Expansion GF	GPIO
PF2	PF2	G1	Expansion GF	GPIO
PF3	PF3	H4	BDET_PF3	Board detect bit 0 (hardcoded)
PF4	PF4	J5	Expansion GF	GPIO
PF5	PF5	J4	BDET_PF5	Board detect bit 1 (hardcoded)
PF6	PF6	K2	Expansion GF	GPIO
PF7	PF7	K3	BDET_PF7	Board detect bit 2 (hardcoded)
PF8	PF8	K4	Expansion GF	GPIO
PF9	PF9	L4	Expansion GF	GPIO
PF10	PF10	L3	Expansion GG	GPIO
PF11	PF11	T7	Motor B Dir	TMC2660 motor B direction
PF12	PF12	R7	Motor B Step	TMC2660 motor B step
PF13	PF13	P7	Expansion GG	GPIO
PF14	PF14	P8	I2C4_SCL	Expansion GG I2C clock
PF15	PF15	R9	I2C4_SDA	Expansion GG I2C data
PG0	PG0	T8	Motor A Step	TMC2660 motor A step
PG1	PG1	U8	Motor A Dir	TMC2660 motor A direction
PG2	PG2	H16	CARD_DET	SD card detection
PG3	PG3	H15	Expansion GB	GPIO
PG4	PG4	H14	Expansion GB	GPIO
PG5	PG5	G14	Expansion GB	GPIO
PG6	PG6	G15	Expansion GC	GPIO
PG7	PG7	F16	Expansion GC	GPIO
PG8	PG8	F15	Expansion GC	GPIO
PG9	PG9	A10	ESXMAX	X max endstop
PG10	PG10	A9	ESXMIN	X min endstop
PG11	PG11	B9	ESYMIN	Y min endstop
PG12	PG12	C9	ESYMAX	Y max endstop
PG13	PG13	D9	ESZMIN	Z min endstop
PG14	PG14	D8	ESZMAX	Z max endstop
PG15	PG15	D6	GPIO	General purpose
PH0	PH0	J2	XTAL_HSE_IN	25MHz crystal in (hardcoded)
PH1	PH1	J1	XTAL_HSE_OUT	25MHz crystal out (hardcoded)
PH2	PH2	N2	ExtraFET	Extra switched output
PH3	PH3	P2	Expansion GG	GPIO
PH4	PH4	P3	Expansion GG	GPIO
PH5	PH5	P4	Expansion GG	GPIO
PH6	PH6	T11	TIM8_CH1	Timer 8 channel 1 PWM
PH7	PH7	U13	TIM8_CH4 / I2C3_SCL	Timer 8 ch4 / I2C3 clock
PH8	PH8	T13	TIM8_CH2 / I2C3_SDA	Timer 8 ch2 / I2C3 data
PH9	PH9	R13	TIM8_CH3	Timer 8 channel 3 PWM
PH10	PH10	P13	Expansion GI	GPIO
PH11	PH11	P14	Expansion GI	GPIO
PH12	PH12	R14	Expansion GI	GPIO
PH13	PH13	D16	MOT_EN	Motor enable (shared, active low)
PH14	PH14	B17	Expansion GI	GPIO
PH15	PH15	B16	GPIO	General purpose
PI0	PI0	A16	MSD LED	Mass storage mode indicator
PI1	PI1	A15	GPIO	General purpose
PI2	PI2	B15	GPIO	General purpose
PI3	PI3	C14	GPIO	General purpose
PI4	PI4	A4	GPIO	General purpose
PI5	PI5	A3	GPIO	General purpose
PI6	PI6	A2	GPIO	General purpose
PI7	PI7	B3	GPIO	General purpose
PI8	PI8	E4	GPIO	General purpose
PI9	PI9	E2	GPIO	General purpose
PI10	PI10	F3	MOTSPI_SCK	Motor SPI clock (hardcoded)
PI11	PI11	F4	Expansion GA	GPIO
PI12	PI12	H1	Expansion GA	GPIO
PI13	PI13	H2	Expansion GA	GPIO
PI14	PI14	H3	Expansion GA	GPIO
PI15	PI15	P5	Expansion GA	GPIO
PJ0	PJ0	N6	Expansion GA	GPIO
PJ1	PJ1	P6	Expansion GA	GPIO
PJ2	PJ2	T6	Motor A CS	TMC2660 motor A chip select
PJ3	PJ3	U6	Motor C CS	TMC2660 motor C chip select
PJ4	PJ4	U7	Motor D CS	TMC2660 motor D chip select
PJ5	PJ5	R12	OUTPUTENABLE	Master FET output enable
PJ6	PJ6	N15	HEA_G	Hotend A MOSFET gate
PJ7	PJ7	N14	HEB_G	Hotend B MOSFET gate
PJ8	PJ8	N13	FAN1_G	Fan 1 MOSFET gate
PJ9	PJ9	M14	FAN2_G	Fan 2 MOSFET gate
PJ10	PJ10	L14	BED_G	Bed MOSFET gate
PJ11	PJ11	K14	SSR2	Solid state relay output 2
PJ12	PJ12	D11	ILED3	Debug LED 3
PJ13	PJ13	E10	ILED2	Debug LED 2
PJ14	PJ14	D10	ILED1	Debug LED 1
PJ15	PJ15	B10	ILED4	Debug LED 4
PK0	PK0	J14	SG_TST_A	Motor A StallGuard output
PK1	PK1	J15	SG_TST_B	Motor B StallGuard output
PK2	PK2	H17	SG_TST_C	Motor C StallGuard output
PK3	PK3	C8	SG_TST_D	Motor D StallGuard output
PK4	PK4	B8	Expansion GB	GPIO
PK5	PK5	A8	Expansion GB	GPIO
PK6	PK6	C7	Expansion GB	GPIO
PK7	PK7	D7	Expansion GB	GPIO
BOOT0	BOOT0	E8	BOOT0	Boot mode (LOW=flash, HIGH=DFU)
NRST	NRST	K1	MCU_RESET	System reset (active low)

Hardwired Pins:

The following pins are hardwired and would need source code changes to modify:

USB Device: PA11, PA12
Debug (SWD): PA13 (SWDIO), PA14 (SWCLK)
SD Card (SDIO): PC8-PC12, PD2
Crystals: PH0, PH1 (HSE), PC14, PC15 (LSE)
Motor SPI: PD14 (MOSI), PE4 (MISO), PI10 (SCK)
Board detect: PF3, PF5, PF7, PE10

All other pins can be reassigned via the configuration file.

MCU Overview

Property	Value
Part Number	STM32H745XIHx
Package	265-pin BGA
Core	Dual-core: Cortex-M7 @ 480MHz + Cortex-M4 @ 240MHz
Flash	2 MB
RAM	1 MB total
FPU	Double-precision (M7), Single-precision (M4)

Note: The M4 core is currently unused/disabled in the V2 firmware. Only the M7 core runs Smoothieware.

Pin Naming Convention

V2 uses several pin naming formats depending on the function:

GPIO Pins

Format: P + Port Letter (A-K) + Pin Number (0-15)
Example: PG0 = Port G, Pin 0

ADC/Thermistor Pins

Format: ADC + Peripheral (1 or 3) + _ + Channel (0-6)
Example: ADC1_0 = ADC1 channel 0 (board temp)
Example: ADC1_1 = ADC1 channel 1 (thermistor 1)
Use this format for thermistor_pin configuration

PWM Pins

Format: PWM + Timer (1 or 2) + _ + Channel (1-4)
Example: PWM1_1 = Timer 1, Channel 1

Pin Modifiers

Modifier	Function	Example
!	Invert signal	PG0!
^	Enable pull-up	PG10^
v	Enable pull-down	PG10v
o	Open-drain mode	PH13o
-	No pull (floating)	PG10-

Motor Driver Pins

TMC2660 Motor Driver Circuit

Each of the 4 drivers uses this identical circuit

The V2 Prime has 4 onboard TMC2660 stepper drivers. All drivers share an SPI bus and enable signal.

Step and Direction Pins

Driver	Axis	Step Pin	Dir Pin	Chip Select	StallGuard
A	Alpha (X)	PG0	PG1	PJ2	PK0
B	Beta (Y)	PF12	PF11	PB12	PK1
C	Gamma (Z)	PE14	PE15	PJ3	PK2
D	Delta (E)	PE10	PE12	PJ4	PK3

Shared Motor SPI Bus

Function	Smoothie Pin	Description
MOSI	PD14	SPI data to drivers (MOTSPI_COPI)
MISO	PE4	SPI data from drivers (MOTSPI_CIPO)
SCK	PI10	SPI clock (MOTSPI_SCK)
Enable	PH13	Shared enable for all drivers (active low)

Thermistor/ADC Pins

Thermistor Input Circuit

4 buffered thermistor inputs via LMV324 op-amp

V2 Prime has 4 buffered thermistor inputs via an LMV324 op-amp buffer, plus additional unbuffered ADC channels.

Buffered Thermistor Inputs

Input	Config Pin	STM32 Pin	Connector	Description
T1	ADC1_1	PF11	J25	Thermistor 1 (Hotend)
T2	ADC1_2	PF12	J24	Thermistor 2 (Bed)
T3	ADC1_3	PB0	J26	Thermistor 3
T4	ADC1_0	PA0_C	J27-J29	Board Temperature

Config Format: Use the ADC channel name (e.g., ADC1_1) in your config file, NOT the STM32 pin name. For example: temperature_control.hotend.thermistor_pin = ADC1_1

Voltage Monitoring ADC Channels

Signal	Smoothie Pin	ADC Channel	Divider Ratio	Purpose
VMOT	PC4	ADC1_CH13	11:1	Motor supply voltage
VFET	PC5	ADC1_CH15	11:1	MOSFET supply voltage
Board Temp	TH1	Internal	-	Onboard thermistor

Endstop Pins

Endstop Input Circuit

6 endstops with ESD protection and configurable pull resistors

6 endstop inputs with ESD protection and configurable pull-up/pull-down via solder jumpers.

Endstop	Smoothie Pin	BGA Pin	Signal	Jumper
X Min	PG10	A9	ESXMIN	JP1
X Max	PG9	A10	ESXMAX	JP2
Y Min	PG11	B9	ESYMIN	JP3
Y Max	PG12	C9	ESYMAX	JP4
Z Min	PG13	D9	ESZMIN	JP5
Z Max	PG14	D8	ESZMAX	JP6

Endstop Pull Configuration Jumpers

Each endstop has a 3-way solder jumper (JP1-JP6) to configure pull-up or pull-down:

Position 1-2 (default): Pull to 3.3V
Position 2-3: Pull to GND
Position 2 center: Pull to 5V

Probe Input

Probe Input Circuit

Probe input with comparator and JP7 voltage range selector

Signal	Smoothie Pin	Connector	Description
PROBE	PB0	J22	Probe input via comparator

CRITICAL - JP7 Jumper:

The probe input voltage range is controlled by jumper JP7 (bottom side near probe input):

JP7 intact (default): Input range 0-5V only
JP7 cut: Input range 2.9V to 26V (for 24V inductive probes)

WARNING: Using a >5V probe with JP7 intact will damage the board!

MOSFET Output Pins

MOSFET Output Circuit

Hotend and fan MOSFET outputs with gate driver

Heater and Fan Outputs

Output	Smoothie Pin	Signal	Connector	Current Rating
Hotend A	PJ6	HEA_G	J17	~5A
Hotend B	PJ7	HEB_G	J18	~5A
Fan 1	PJ8	FAN1_G	J19	~5A
Fan 2	PJ9	FAN2_G	J20	~5A
Bed	PJ10	BED_G	J13-J14	~10-12A

Safety Feature: Hotend A, Hotend B, Fan 1, and Fan 2 are controlled by a highside PFET cutoff circuit. The bed FET is independent and not affected by the cutoff.

SSR and Extra Outputs

Output	Smoothie Pin	Signal	Connector	Description
SSR1	PC0	SSR1	J44	Logic-level SSR output
SSR2	PJ11	SSR2	J45	Logic-level SSR output
ExtraFET	PH2	ExtraFET	-	Additional switched output

Output Enable

Signal	Smoothie Pin	Description
OUTPUTENABLE	PJ5	Master enable for all FET outputs

PWM/Timer Pins

V2 has multiple hardware timer channels available for PWM:

Timer 1 Channels

Channel	Smoothie Pin	BGA Pin	Function
TIM1_CH1	PE9	P9	PWM output
TIM1_CH2	PE11	P10	PWM output
TIM1_CH3	PE12	R10	PWM output
TIM1_CH4	PE13	T10	PWM output (spare)

Timer 8 Channels

Channel	Smoothie Pin	BGA Pin	Function
TIM8_CH1	PH6	T11	PWM output
TIM8_CH2	PH8	T13	PWM output
TIM8_CH3	PH9	R13	PWM output
TIM8_CH4	PH7	U13	PWM output

Communication Interfaces

USB Host + Device Circuit

USB-B device connector with SD card interface

USB Device

Signal	Smoothie Pin	BGA Pin	Connector
USB_DEV_D+	PA12	E16	J1 (USB-B)
USB_DEV_D-	PA11	E17	J1 (USB-B)

USB Host

Signal	Smoothie Pin	BGA Pin	Connector
USB_HOST_D+	PB14	U15	J2 (USB-A)
USB_HOST_D-	PB15	T15	J2 (USB-A)
USB_PWR_ON	PB13	U14	Host power control

Note: USB Host functionality has hardware support but firmware is not yet implemented.

Ethernet (RMII)

Ethernet PHY Circuit

LAN8720A PHY with RJ45 connector and magnetics

Signal	Smoothie Pin	Description
ETH_TXD0	PG13	Transmit data 0
ETH_TXD1	PG12	Transmit data 1
ETH_TXEN	PG11	Transmit enable
ETH_RXD0	PC4	Receive data 0
ETH_RXD1	PC5	Receive data 1
ETH_CRSDV	PA7	Carrier sense/data valid
ETH_MDIO	PA2	Management data I/O
ETH_MDC	PC1	Management data clock
ETH_REFCLK	PA1	50MHz reference clock

I2C Buses

Bus	SDA Pin	SCL Pin	Purpose
I2C2	PB1	PA4	User I2C
I2C3	PH8	PH7	Additional I2C

UART/USART

UART	TX Pin	RX Pin	Purpose
USART3	PD8	PD9	Available on expansion
UART4	PD1	PD0	Available on expansion

SPI Buses

Bus	MOSI	MISO	SCK	Purpose
Motor SPI	PD14	PE4	PI10	TMC2660 drivers
SPI1	PB5	PB4	PB3	User SPI (displays)

Storage

MicroSD (SDIO Interface)

Signal	Smoothie Pin	Description
SD_D0	PC8	Data line 0
SD_D1	PC9	Data line 1
SD_D2	PC10	Data line 2
SD_D3	PC11	Data line 3
SD_CMD	PD2	Command
SD_CK	PC12	Clock
CARD_DET	PG2	Card detection

Performance: V2 uses SDIO interface (10-25 MB/s) instead of V1's SPI interface (~0.5 MB/s) - approximately 20-50× faster!

QSPI Flash

QSPI Flash Circuit

Quad-SPI flash for firmware storage

Signal	Smoothie Pin	Description
QSPI_IO0	PD11	Data 0
QSPI_IO1	PD12	Data 1
QSPI_IO2	PE2	Data 2
QSPI_IO3	PD13	Data 3
QSPI_SCK	PB2	Clock
QSPI_CS	PB6	Chip select

Debug Interface

SWD/JTAG Debug Interface

Standard ARM debug connector with UART

SWD/JTAG (J41)

Pin	Signal	Smoothie Pin	Description
1	VTref	3V3	Reference voltage
2	SWDIO	PA13	Debug data
3	GND	GND	Ground
4	SWCLK	PA14	Debug clock
5	GND	GND	Ground
6	SWO	PB3	Trace output
8	TDI	PA15	JTAG data in
10	RESET	NRST	System reset

Debug UART (J30)

Pin	Signal	Smoothie Pin	Description
1	GND	GND	Ground
2	RX	PD6	MCU receive (connect to TX)
3	TX	PD5	MCU transmit (connect to RX)

Baud rate: 115200 8N1

System Pins

Crystals

Crystal	Frequency	Input Pin	Output Pin	Purpose
HSE	25 MHz	PH0	PH1	Main system clock
LSE	32.768 kHz	PC14	PC15	RTC clock

Boot Configuration

Signal	Smoothie Pin	BGA Pin	Description
BOOT0	BOOT0	E8	Boot mode (LOW=flash, HIGH=DFU)
NRST	NRST	K1	System reset (active low)

Board Detection

Signal	Smoothie Pin	BGA Pin	Description
BDET_PF3	PF3	H4	Board ID bit 0
BDET_PF5	PF5	J4	Board ID bit 1
BDET_PF7	PF7	K3	Board ID bit 2
BDET_PE10	PE10	N9	Board ID bit 3

Board ID values:

ID 0 (0000)
: V2 Prime with TMC2590 drivers
ID 1 (0001)
: V2 Prime with TMC2660 drivers

LED Indicators

LED Indicator Circuit

4 debug LEDs showing boot progress

LED	Smoothie Pin	Signal	Description
LED1	PJ14	ILED1	Debug LED 1 (boot phase 4)
LED2	PJ13	ILED2	Debug LED 2 (boot phase 3)
LED3	PJ12	ILED3	Debug LED 3 (boot phase 2)
LED4	PJ15	ILED4	Debug LED 4 (boot phase 1)
MSD	PI0	MSD	Mass storage mode indicator

Gadgeteer Expansion Headers

Expansion Headers Schematic

9 Gadgeteer-style 10-pin expansion headers

V2 Prime has 9 Gadgeteer-style 10-pin expansion headers (GA through GI).

Standard Header Pinout

All headers follow this pinout:

Pin	Function
1	3.3V
2	5V
3-9	GPIO (varies by header)
10	GND

Header Pin Assignments

Header GA (J32) - Motor SPI / Encoder

Pin	Smoothie Pin	Alternate Function
3	PJ0	GPIO
4	PJ1	GPIO
5	PI11	GPIO
6	PI12	GPIO
7	PI13	GPIO
8	PI14	GPIO
9	PI15	GPIO

Header GB (J33)

Pin	Smoothie Pin	Alternate Function
3	PK4	GPIO
4	PK5	GPIO
5	PK6	GPIO
6	PK7	GPIO
7	PG3	GPIO
8	PG4	GPIO
9	PG5	GPIO

Header GC (J34)

Pin	Smoothie Pin	Alternate Function
3	PG6	GPIO
4	PG7	GPIO
5	PG8	GPIO
6	PC6	GPIO
7	PC7	GPIO
8	PD15	GPIO
9	PD14	GPIO

Header GD (J35) - UART / PWM

Pin	Smoothie Pin	Alternate Function
3	PD0	UART4_RX
4	PD1	UART4_TX
5	PD3	GPIO
6	PD4	GPIO
7	PD5	USART2_TX
8	PD6	USART2_RX
9	PD7	GPIO

Header GE (J36) - Timer / PWM

Pin	Smoothie Pin	Alternate Function
3	PE0	GPIO
4	PE1	GPIO
5	PE3	GPIO
6	PE5	TIM15_CH1
7	PE6	TIM15_CH2
8	PE7	GPIO
9	PE8	GPIO

Header GF (J37)

Pin	Smoothie Pin	Alternate Function
3	PF0	GPIO
4	PF1	GPIO
5	PF2	GPIO
6	PF4	GPIO
7	PF6	GPIO
8	PF8	GPIO
9	PF9	GPIO

Header GG (J38) - I2C

Pin	Smoothie Pin	Alternate Function
3	PF10	GPIO
4	PF13	GPIO
5	PF14	I2C4_SCL
6	PF15	I2C4_SDA
7	PH3	GPIO
8	PH4	GPIO
9	PH5	GPIO

Header GH (J39) - ADC

Pin	Smoothie Pin	Alternate Function
3	PA3	ADC1_CH15
4	PA5	DAC1_OUT2
5	PA6	ADC1_CH3
6	PB0	ADC1_CH9
7	PB1	ADC1_CH5
8	PA8	GPIO
9	PA9	GPIO

Header GI (J40)

Pin	Smoothie Pin	Alternate Function
3	PA10	GPIO
4	PH10	GPIO
5	PH11	GPIO
6	PH12	GPIO
7	PB10	GPIO
8	PB11	GPIO
9	PH14	GPIO

Complete BGA Pin Reference

ADC Channel Mapping (Thermistors)

The firmware maps ADC channel names to physical pins. Use the Config Pin in your config files:

Config Pin	STM32 Pin	ADC Hardware	Typical Use
ADC1_0	PA0_C	ADC1_INP0	Board Temperature (T4)
ADC1_1	PF11	ADC1_INP2	Thermistor 1 (T1)
ADC1_2	PF12	ADC1_INP6	Thermistor 2 (T2)
ADC1_3	PB0	ADC1_INP9	Thermistor 3 (T3)
ADC1_4	PC2	ADC1_INP12	Expansion (GH)
ADC1_5	PC3	ADC1_INP13	Expansion (GH)
ADC1_6	PA3	ADC1_INP15	Expansion (GH)

Power Pins Summary

Type	Count	Voltage
VDD	15	3.3V
VSS	30+	GND
VDDA	1	3.3V (analog)
VSSA	1	GND (analog)
VREF+	1	3.3V (ADC ref)
VREF-	1	GND (ADC ref)
VBAT	1	3V (RTC backup)
VDDLDO	3	1.2V (internal)
VCAP	3	1.2V (core caps)

STM32H7 ADC Channels Summary

This table shows the relationship between Smoothieware config names and STM32 hardware.

Config Name	STM32 Pin	ADC Hardware	Assignment
ADC1_0	PA0_C	ADC1_INP0	Board Temperature
ADC1_1	PF11	ADC1_INP2	Thermistor 1
ADC1_2	PF12	ADC1_INP6	Thermistor 2
ADC1_3	PB0	ADC1_INP9	Thermistor 3
ADC1_4	PC2	ADC1_INP12	Expansion (GH)
ADC1_5	PC3	ADC1_INP13	Expansion (GH)
ADC1_6	PA3	ADC1_INP15	Expansion (GH)
ADC3_0	PC0	ADC3_INP10	Voltage Monitor
PC4	PC4	ADC1_INP4	VMOT sense
PC5	PC5	ADC1_INP8	VFET sense

Important: ADC pins are NOT 5V tolerant. Maximum input voltage is 3.3V. The buffered thermistor inputs (T1-T4) have protection circuitry; unbuffered ADC pins on expansion headers do not.

Hardcoded vs Configurable Pins

Hardcoded Pins:

The following pins are hardcoded in firmware and would need source code changes to modify:

USB Device: PA11, PA12
Debug: PA13 (SWDIO), PA14 (SWCLK)
SD Card (SDIO): PC8-PC12, PD2
Crystals: PH0, PH1, PC14, PC15
Motor SPI: PD14, PE4, PI10
Board detect: PF3, PF5, PF7, PE10