Difference between revisions of "Fitlet GPIO SDK for Linux"
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* A basic example of GPIO P-1 (Brown) usage (as root user): | * A basic example of GPIO P-1 (Brown) usage (as root user): | ||
− | $ modprobe | + | $ modprobe gpio_fch |
$ echo 89 > /sys/class/gpio/export | $ echo 89 > /sys/class/gpio/export | ||
$ echo out > /sys/class/gpio/gpio89/direction | $ echo out > /sys/class/gpio/gpio89/direction |
Revision as of 07:52, 11 January 2016
Contents
Overview
- Not supported in mainline Linux kernel
- Linux Kernel for Fitlet must be installed to make this feature work
- GPIO interface on fitlet consists of 9 GPIOs provided by AMD FCH (Fusion Controller Hub)
- The responsible kernel module is gpio_fch
- The kernel module uses the following pin naming convention:
Pin Number | Color Code | GPIO name | Power domain | HW source | Notes |
1 | Brown | GPIO89 | 3.3V | SoC | |
2 | Red | GPIO132 | 3.3V | SoC | |
3 | Orange | GPIO65 | 3.3V | SoC | |
4 | Yellow | GPIO66 | 3.3V | SoC | |
5 | Green | GPIO29 | 1.5V | Soc | |
6 | Blue | I2C Clock | 3.3V | SoC | |
7 | Purple | I2C Data | 3.3V | SoC | |
8 | Grey | GPIO73 | 3.3V | SoC | |
9 | White | GPIO27 | 1.5V | SoC | |
10 | Black | GPIO28 | 1.5V | SoC | |
11 | Brown | GPIO12 | 3.3V | SoC | |
12 | Red | UART Rx | 3.3V | SuperIO | |
13 | Orange | UART Tx | 3.3V | SuperIO | |
14 | Yellow | GND |
Usage
- The GPIO sysfs interface allows users to manipulate any GPIO from userspace dynamically.
- A basic example of GPIO P-1 (Brown) usage (as root user):
$ modprobe gpio_fch $ echo 89 > /sys/class/gpio/export $ echo out > /sys/class/gpio/gpio89/direction $ echo 1 > /sys/class/gpio/gpio89/value ## at this point voltage measuring on P-1 (Brown) should give 3.3V $ echo 0 > /sys/class/gpio/gpio89/value ## at this point voltage measuring on P-1 (Brown) should give 0.0V $ echo 89 > /sys/class/gpio/unexport
Documentation
- The GPIO framework and GPIO sysfs interface are documented in https://www.kernel.org/doc/Documentation/gpio/gpio.txt