Pin Assignments

This page documents the GPIO pin assignments for both NanoVNA-H (STM32F072) and NanoVNA-H4 (STM32F303) hardware platforms.

Pin Assignment Tables

GPIOA

Port A Pin Assignments

Pin	F072 Function	F303 Function	Mode	Notes
PA0	BUTTON (unused)	BUTTON	Input	Not used in firmware
PA1	LEVER1	LEVER1	Input	Jog wheel encoder A
PA2	PUSH	PUSH	Input	Jog wheel push button
PA3	LEVER2	LEVER2	Input	Jog wheel encoder B
PA4	-	VBUS	Input	USB VBUS detect (H4)
PA5	DAC2	DAC2	Analog	LCD backlight control
PA6	XP	XP	Analog	Touch panel X+
PA7	YP	YP	Analog	Touch panel Y+
PA8	MCO	MCO	AF0	Master clock output
PA9	USART1_TX	USART1_TX	AF1/AF7	Serial console TX
PA10	USART1_RX	USART1_RX	AF1/AF7	Serial console RX
PA11	USB_DM	USB_DM	AF14	USB D-
PA12	USB_DP	USB_DP	AF14	USB D+
PA13	SWDIO	SWDIO	AF0	Debug interface
PA14	SWCLK	SWCLK	AF0	Debug interface
PA15	LCD_RESET	LCD_RESET	Output	LCD reset signal

GPIOB

Port B Pin Assignments

Pin	F072 Function	F303 Function	Mode	Notes
PB0	XN	XN	Analog	Touch panel X-
PB1	YN	YN	Analog	Touch panel Y-
PB2	SD_GP1	SD_GP1	Output	SD card GPIO
PB3	SPI_SCLK	SPI_SCLK	AF0/AF5	SPI clock
PB4	SPI_MISO	SPI_MISO	AF0/AF5	SPI data in
PB5	SPI_MOSI	SPI_MOSI	AF0/AF5	SPI data out
PB6	LCD_CS	LCD_CS	Output	LCD chip select
PB7	LCD_CD	LCD_CD	Output	LCD data/command
PB8	I2C1_SCL	I2C1_SCL	AF1/AF4	I2C clock (Si5351)
PB9	I2C1_SDA	I2C1_SDA	AF1/AF4	I2C data (Si5351)
PB10	SD_GP2	SD_GP2	Output	SD card GPIO
PB11	SD_CS	SD_CS	Output	SD card chip select
PB12	I2S2_WCLK	I2S2_WCLK	AF0/AF5	I2S word clock
PB13	I2S2_BCLK	I2S2_BCLK	AF0/AF5	I2S bit clock
PB14	-	I2S2_MISO	AF0/AF5	I2S data in (H4)
PB15	I2S2_MOSI	I2S2_MOSI	AF0/AF5	I2S data out

GPIOC/F

Port C Pin Assignments

Pin	F072 Function	F303 Function	Mode	Notes
PC0-12	-	-	Input	Unused
PC13	LED	LED	Output	Status LED
PC14	OSC32_IN	OSC32_IN	Input	32.768 kHz crystal
PC15	OSC32_OUT	OSC32_OUT	Input	32.768 kHz crystal

Port F Pin Assignments

Pin	Function	Mode	Notes
PF0	OSC_IN	Input	8 MHz crystal input
PF1	OSC_OUT	Output	8 MHz crystal output

Peripheral Connections

SPI Bus (LCD and SD Card)

SPI1:
  SCLK  -> PB3
  MISO  -> PB4
  MOSI  -> PB5

LCD:
  CS    -> PB6
  DC    -> PB7
  RESET -> PA15

SD Card:
  CS    -> PB11
  GP1   -> PB2
  GP2   -> PB10

I2C Bus (Si5351 Synthesizer)

I2C1:
  SCL   -> PB8
  SDA   -> PB9

Si5351 Address: 0x60 (7-bit)
TLV320AIC3204 Address: 0x18 (7-bit)

I2S Bus (Audio Codec)

I2S2:
  WCLK  -> PB12  (Word select / LRCLK)
  BCLK  -> PB13  (Bit clock)
  MOSI  -> PB15  (Data to codec)
  MISO  -> PB14  (Data from codec, H4 only)

USART (Serial Console)

USART1:
  TX    -> PA9
  RX    -> PA10

Alternate Function:
  F072: AF1
  F303: AF7

USB

USB:
  DM    -> PA11
  DP    -> PA12
  VBUS  -> PA4 (H4 detection)

VID: 0x0483 (STMicroelectronics)
PID: 0x5740 (Virtual COM Port)

User Input

Jog Wheel Encoder

Encoder:
  A     -> PA1 (LEVER1)
  B     -> PA3 (LEVER2)
  Push  -> PA2 (PUSH)

Input Mode: Pull-down resistors enabled

Touch Panel (Resistive)

Touch ADC:
  X+    -> PA6 (ADC channel 6)
  Y+    -> PA7 (ADC channel 7)
  X-    -> PB0
  Y-    -> PB1

Clock Configuration

External Oscillators

Oscillator	Frequency	Pins	Notes
HSE	8 MHz	PF0/PF1	Main system clock source
LSE	32.768 kHz	PC14/PC15	RTC clock (optional)

System Clocks

Target	SYSCLK	HCLK	APB
F072	48 MHz	48 MHz	48 MHz
F303	72 MHz	72 MHz	72 MHz

MCO Output

PA8 can output a clock signal (used for audio codec reference):

#define AUDIO_CLOCK_REF  8000000U  // 8 MHz to codec

DMA Channels

DMA Channel	Function	Source/Dest
DMA1_CH4	I2S RX	Audio samples from codec
DMA1_CH5	SPI TX	Display data (if DMA enabled)

Alternate Function Summary

F072 Alternate Functions

AF	Function	Pins
AF0	MCO, SPI1, I2S2, SWDIO	Multiple
AF1	USART1, I2C1	PA9/PA10, PB8/PB9
AF14	USB	PA11/PA12

F303 Alternate Functions

AF	Function	Pins
AF0	MCO, SWDIO	PA8, PA13/PA14
AF4	I2C1	PB8/PB9
AF5	SPI1, I2S2	PB3-5, PB12-15
AF7	USART1	PA9/PA10
AF14	USB	PA11/PA12

Debug Interface

SWD Connection

SWD:
  SWDIO -> PA13
  SWCLK -> PA14

GND and 3.3V required

Use with OpenOCD + CMSIS-DAP adapter:

openocd -f NanoVNA_DAP.cfg

DFU Boot Mode

To enter DFU bootloader:

1. Hardware method: Short BOOT0 to VCC during power-on
2. Software method: Menu CONFIG > EXPERT SETTINGS > DFU
3. Shell command: reset dfu

DFU uses USB in bootloader mode (built into STM32 ROM).

Source Code Reference

Pin definitions are located in:

• F072 pins: NANOVNA_STM32_F072/board.h lines 48-88
• F303 pins: NANOVNA_STM32_F303/board.h lines 48-90
• ADC channels: hardware.h lines 31-36