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Manage the GPIO lines using the sysfs user interface (deprecated)
GPIO sysfs is the legacy way to manage the GPIO lines under Linux from user space.
It uses the directory /sys/class/gpio to set or read any GPIO line.
replaced with the GPIO character device.
Inside this directory there are two directories called:
To manage a GPIO line you have to know its kernel ID. The Kernel
IDs of any Acme Systems SoM are available on:
Check the port available by typing this command:
sudo less /sys/kernel/debug/pinctrl/fc038000.pinctrl-atmel_pinctrl/pinconf-pins
The Microchip chips have the GPIO lines organized by 32 bit port called PA,PB, etc.
Before set or read a port you have to export it. Follow an example on how to set, reset
and read the port PA1 (Kernel ID 1) from the command line:
Set the line status of GPIO line PA1
sudo sh -c "echo 1 > /sys/class/gpio/export"
sudo sh -c "echo out > /sys/class/gpio/PA1/direction"
sudo sh -c "echo 1 > /sys/class/gpio/PA1/value"
Reset the line status of GPIO line PA1
sudo sh -c "echo 0 > /sys/class/gpio/PA1/value"
Read the line status of GPIO line PA1
sudo sh -c "echo in > /sys/class/gpio/PA1/direction"
The official documentation about the GPIO Sysfs interface is available on:
Low-power Linux System On Module
- CPU Microchip SAMA5D27
- Cortex A5 @ 500 MHz
- Low power consumption:
Suspend to RAM mode 10mW
Full speed: 396mW
- Debian, Buildroot and Yocto Linux
- Fully open source drivers
- Low power consumption
- Two USB Host 2.0 ports (one configurable as USB client on the USB-C connector)
- One 10/100 Mbit/s Lan port
- 2 Acme Sensor ports
- Huge set of GPIOS, SPI, I2C and serial lines
Evaluation board for RoadRunner SOM
- All the circuitries you need to test the RoadRunner SOM
- USB host, USB device, Ethernet port, MicroSD socket
- Test points for power consumption measurements
- All the Roadrunner signals exposed on 2.54mm pitch pins
- On-board supercap for RTC and backup memory circuit
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