Fan Interface
The Radxa Cubie A7A features an onboard fan interface that supports connecting a fan using a 2-Pin 1.25mm cable (fan operating voltage: 5V) to provide cooling for the mainboard.
For the exact location of the fan interface, please refer to the interface description section in the Hardware Interface guide!
User Guide
Connect a fan to the fan interface with the following specifications:
- Interface Type: 2-Pin 1.25mm
- Operating Voltage: 5V
Pay attention to the positive and negative polarity when connecting the fan.
Checking Fan Device
- Use the
lscommand to view registered fan devices in the system.
ls /sys/devices/platform/ | grep fan
Terminal output will be similar to:
pwm-fan
pwm-fan: Control device for the onboard fan
- Locate the PWM Control File
PWM control files for the fan are typically located in the /sys/class/hwmon/ directory. You need to find the hwmon directory corresponding to pwm-fan.
Use the ls command to view the PWM control files for the pwm-fan device.
ls /sys/class/hwmon/
Terminal output will be similar to:
hwmon0
- Identify the Fan Control Node
Use the ls command to view the PWM control files for the pwm-fan device in the hwmon directory.
ls -l /sys/class/hwmon/hwmon*/device
Terminal output will be similar to:
/sys/class/hwmon/hwmon0/device -> ../../../pwm-fan
Based on the terminal output, we can control the pwm-fan through hwmon0.
Controlling Fan Speed
Use the echo command to set the fan speed. The PWM control range is typically 0~255 (0=stop, 255=full speed).
- Full Speed
echo 255 | sudo tee /sys/class/hwmon/hwmon0/pwm1
- Half Speed
echo 128 | sudo tee /sys/class/hwmon/hwmon0/pwm1
- Turn Off Fan
echo 0 | sudo tee /sys/class/hwmon/hwmon0/pwm1
Interface Specifications
For complete technical specifications and pin definitions, please refer to the Hardware Design: Schematics document in the download section.