Orange Pi Zero 2¶

You can use the Orange Pi Zero 2, a compact SBC based on the Allwinner H616 SoC. Your board provides a 26-pin GPIO header and is supported by MainsailOS through an Armbian-based image.

Board Overview¶

GPIO Pinout¶

GPIO Chip¶

When using GPIOs with the Linux MCU in Klipper, you need to identify the correct GPIO chip and line number for each pin. The H616 SoC exposes two GPIO controllers:

Header Pin Mapping¶

The following table lists all GPIO pins on the 26-pin header with their Klipper pin references:

Calculating GPIO Line Numbers¶

Allwinner SoCs use a simple formula to convert pin names (e.g., PH9) to GPIO line numbers:

line number = port base + pin number

Where port base values are: PA=0, PB=32, PC=64, PD=96, PE=128, PF=160, PG=192, PH=224, PI=256, PL=0.

Example: PH9 → port base 224 + pin 9 = 233 → Klipper pin: host:gpiochip1/gpio233

UART¶

UART5 is enabled by default in MainsailOS via the uart5 device tree overlay. The UART is immediately available after the first boot.

SPI¶

SPI1 is enabled by default in MainsailOS via the spi-spidev and spidev1_1 device tree overlays. It is pre-configured for use with accelerometers for Input Shaper.

The SPI device is available at /dev/spidev1.1.

Example Klipper configuration for an ADXL345 accelerometer:

[adxl345]
cs_pin: host:gpiochip1/gpio233
spi_bus: spidev1.1

I2C¶

I2C3 is enabled by default in MainsailOS via the i2c3-ph device tree overlay. The I2C device is available at /dev/i2c-1.

In your Klipper configuration, use i2c_bus: i2c.1:

[temperature_sensor example]
sensor_type: HTU21D
i2c_mcu: host
i2c_bus: i2c.1

Further Resources¶

• Orange Pi Zero 2 — Official Page
• Armbian Documentation
• Klipper RPi Microcontroller — Klipper Linux MCU guide