You can use your Flipper Zero for hardware exploration, firmware flashing, debugging, and fuzzing. Flipper Zero can be connected to hardware using its built-in GPIO pins, control hardware with buttons, run your code, and show debug messages on the LCD screen. Flipper Zero can also be used as a USB to UART/SPI/I2C converter.

Flipper Zero has 18 pins on the top side, consisting of power supply pins and I/O pins. Power supply pins can be used to power your external modules. Input/output (I/O) pins are +3.3 V tolerant for input and output, some pins are +5 V tolerant for input only - keep it in mind. I/O pins connect external modules to the I/O pins of the STM32WB55 microcontroller through 51 Ohm resistors. All pins are electrostatic discharge (ESD) protected. For information on the basic functionality of Flipper Zero pins, see the picture below.

Detailed information on the pinout and functionality of the pins can be found in the picture below.

• The output is enabled by default.
• The maximum load is 1200 mA.
• Flipper Zero's microSD card is powered by +3.3 V. During firmware update and a microSD card mounting, power supply to pin 9 is temporarily disabled.

Pin 1 can be supplied with power by the built-in battery or a USB cable.

When Flipper Zero is powered by the built-in battery:

• The output is not enabled by default. To enable power supply to pin 1, do the following: 1. In the Main Menu, go to GPIO. 2. Select 5V on GPIO and set it to ON.
• The maximum load is 1000 mA.

Total power consumption from I/O pins must not exceed 5 watts, otherwise, the battery might switch to the protection mode and Flipper Zero might shut down. Each pin can source up to 20 mA.

You can access the GPIO application from the Main Menu. In the application, you can configure USB-UART functionality, test pins separately, and enable/disable the +5V power supply to pin 1.

• USB-UART Bridge — Flipper Zero acts as a USB to Serial UART converter.
• GPIO Manual Control — test output of individual or all GPIO pins by pressing OK:ok:. Available configuring options: PA7 (pin 2), PA6 (pin 3), PA4 (pin 4), PB3 (pin 5), PB2 (pin 6), PC3 (pin 7), PC1 (pin 15), PC0 (pin 16), and ALL.
• 5V on GPIO — enable/disable +5V power supply to pin 1. See this section for more information.

It's important to insert the external module into your Flipper Zero's GPIO pin holes correctly. If your Flipper Zero isn't in a silicone case, insert the module all the way in, so there is no gap between your Flipper Zero and the module. You may need to apply more force to insert it completely.

If your Flipper Zero is in a silicone case, insert the module all the way in, so there is no gap in the middle between the silicone case and the module.