Flipper Zero GPIO Pinout

Flipper Zero is a pocket multi-tool for radio, RFID, NFC, infrared remote control and 1-Wire. On its top edge it has an 18-pin GPIO connector for modules and your own electronics – SPI, I2C, UART, analog inputs, SWD debugging and 5 V and 3.3 V power.

It’s controlled by the STM32WB55 chip; the pins have shortened names on the case (A7, B3, C1…).

Specifications

STM32WB55RG: ARM Cortex-M4 64 MHz + Cortex-M0+ for Bluetooth LE
18-pin GPIO connector (2.54 mm pitch, 8 + 10 pins), 3.3 V logic
external SPI (pins 2–5), I2C (15, 16), UART (13, 14 or 15, 16), 6 analog inputs
5 V and 3.3 V outputs, each max. 1.2 A
SWD for debugging (pins 10, 12), 1-Wire / iButton (pin 17)
100.3 × 40.1 × 25.6 mm

The diagram shows the Flipper rotated by 90° – the tip with the IR window at the top, the GPIO connector on the right, pin 1 (5 V) near the tip. The Flipper column lists the pin names from the case and apps, with the STM32 chip port next to them.

The functions in the table match the Flipper firmware: external SPI is SPI1, external I2C is I2C3 at 100 kHz without pull-ups, UART is USART1 (pins 13, 14) or LPUART1 (pins 15 = TX, 16 = RX). The GPIO app also includes a USB-UART bridge.

Pinout and pin table

Hover over a pin in the diagram or a table row; use the filter to highlight a bus. You can download the pinout as PNG or SVG.

Download:PNG SVG

License: CC BY 4.0 · How to credit

Pin table – Flipper Zero
Pin	Name	Flipper	Direction	UART	I2C	SPI	PWM	ADC	Note
GPIO 1	5V		output						Off on battery – enable it in the app under GPIO → 5V on GPIO. With USB connected it carries USB voltage directly. Max. draw 1.2 A (fuse).
GPIO 2	PA7	A7	input/output			MOSI	TIM1_CH1N	ADC1_IN12	External bus SPI MOSI (SPI1 – shares the peripheral with the internal radio bus), ADC, PWM (TIM1_CH1N). Also I2C3 SCL in the Flipper schematic – not used by the firmware.
GPIO 3	PA6	A6	input/output			MISO		ADC1_IN11	SPI MISO, ADC. Shares its interrupt with the Down button.
GPIO 4	PA4	A4	input/output			CS	LPTIM2_OUT	ADC1_IN9	SPI CS (software-controlled), ADC, PWM (LPTIM2_OUT).
GPIO 5	PB3	B3	input/output			SCK			SPI SCK. Shares its interrupt (EXTI) with the OK button.
GPIO 6	PB2	B2	input/output						General-purpose I/O. Interrupt shared with NFC.
GPIO 7	PC3	C3	input/output					ADC1_IN4	ADC. Shares its interrupt with the OK button.
GPIO 8	GND		–
GPIO 9	3V3		output						3.3 V output, max. 1.2 A
GPIO 10	PA14	SWC	input/output						SWD SWCLK (debugging)
GPIO 11	GND		–
GPIO 12	PA13	SIO	input/output						SWD SWDIO. Shares its interrupt with the Back button; not available in manual GPIO control.
GPIO 13	PB6	TX	input/output	TX					USART1 TX – default for the USB-UART bridge
GPIO 14	PB7	RX	input/output	RX					USART1 RX – default for the USB-UART bridge
GPIO 15	PC1	C1	input/output		SDA			ADC1_IN2	I2C SDA of the external bus (I2C3, 100 kHz, no pull-ups – add your own), or LPUART TX (USB-UART bridge "15,16"), ADC. Shares its interrupt with Sub-GHz.
GPIO 16	PC0	C0	input/output		SCL			ADC1_IN1	I2C SCL (I2C3), or LPUART RX, ADC.
GPIO 17	PB14	1W	input/output						iButton / 1-Wire, 1 kΩ pull-up to 5 V. The only pin that does not change state in DFU mode.
GPIO 18	GND		–

What to watch out for

The pins tolerate 5 V only as a digital input – not as an output and not in analog mode.
The 5 V output is off on battery (GPIO → 5V on GPIO); with USB connected, it’s always live.
Keep the total draw from the connector under 5 W, otherwise the battery protection shuts the Flipper down.
The 3.3 V output briefly drops out when an SD card is inserted and during updates.
Pin 17 (1-Wire) has a 1 kΩ pull-up to 5 V.
Connect modules with large capacitance only to a powered-off Flipper – otherwise data on the SD card may be corrupted.