Fitlet GPIO SDK for Linux
From fit-PC wiki
Installation
- Download the kernel image and kernel headers to the fitlet.
- Open the terminal and install the new linux-*.deb packages:
$ sudo dpkg -i /path/to/linux-*.deb
- Reboot the system:
$ sudo reboot -f
GPIO
- 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 | HW source | Notes |
P-1 | Brown | GPIO89 | FCH | |
P-2 | Red | GPIO132 | FCH | |
P-3 | Orange | GPIO65 | FCH | |
P-4 | Yellow | GPIO66 | FCH | |
P-5 | Green | GPIO29 | FCH | Vout 1.5V |
P-8 | Grey | GPIO73 | FCH | |
P-9 | White | GPIO27 | FCH | Vout 1.5V |
P-10 | Black | GPIO28 | FCH | Vout 1.5V |
P-11 | Brown | GPIO12 | FCH |
GPIO
Connector |
Source | Function/
GPIO# |
GPIO# in
Linux |
Power
domain |
Direction/
Drive |
Pull
(PU/PD) | |
---|---|---|---|---|---|---|---|
Pin
Number |
Color
Code | ||||||
1 | Brown | SoC | GPIO_1 | GPIO89 | 3.3V | In | PU |
2 | Red | SoC | GPIO_2 | GPIO132 | 3.3V | In | PU |
3 | Orange | SoC | GPIO_3 | GPIO65 | 3.3V | Out/High | PU |
4 | Yellow | SoC | GPIO_4 | GPIO66 | 3.3V | Out/High | PU |
5 | Green | SoC | GPIO_5 | GPIO29 | 1.5V | In | PD |
6 | Blue | SoC | I2C Clock | 3.3V | |||
7 | Purple | SoC | I2C Data | 3.3V | |||
8 | Grey | SoC | GPIO_6 | GPIO73 | 3.3V | Out/Low | PD |
9 | White | SoC | GPIO_7 | GPIO27 | 1.5V | In | PD |
10 | Black | SoC | GPIO_8 | GPIO28 | 1.5V | In | PD |
11 | Brown | SoC | GPIO_9 | GPIO12 | 3.3V | In | PU |
12 | Red | SuperIO | UART Rx | 3.3V | |||
13 | Orange | SuperIO | UART Tx | 3.3V | |||
14 | Yellow | GND |
- The GPIO sysfs interface allows users to manipulate any GPIO from userspace dynamically.
- A basic example of GPIO usage (as root user):
$ modprobe fch_gpio $ 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
- The source code of gpio_fch driver fitlet.gpio.3.16.diff
- The GPIO framework and GPIO sysfs interface are documented in Linux Kernel Documentation :: GPIO