How to access GPIO


#1

Here is about how to access GPIO on Android and Ubuntu
###Preconditions
The Rom must satisfy the following conditions

  • Android M >= V170603
  • Android N >= V170421
  • Ubuntu Server >= V170515
  • Ubuntu Mate >= V170605

###1. On Android

GPIO List

PIN         GPIO         Number
PIN37       GPIOH5         176
PIN33       GPIOAO6        151

There are two ways to access GPIO:

  • ADB Command
  • Third-Party Applications

ADB command

Connect the vim with wifi adb:

$ adb connect IP_ADDR 

Login the vim:

$ adb shell

Get root permision

$ su

Request the gpio(GPIOH5)

$ echo 176  > /sys/class/gpio/export

Config the gpio(GPIOH5) as output

$ echo out > /sys/class/gpio/gpio176/direction

Config the gpio(GPIOH5) as high level output

$ echo 1 >  /sys/class/gpio/gpio176/value

Config the gpio(GPIOH5) as low level output

$ echo 0 >  /sys/class/gpio/gpio176/value

Config the gpio(GPIOH5) as input

$ echo in > /sys/class/gpio/gpio176/direction

Get the gpio(GPIOH5) level

$ cat /sys/class/gpio/gpio176/value

Release the gpio(GPIOH5)

$ echo 176 > /sys/class/gpio/unexport

####Third-Party Applications

Get root permision

Process mProcess = Runtime.getRuntime().exec("su");

Request the gpio(GPIOH5)

DataOutputStream os = new DataOutputStream(mProcess.getOutputStream());
os.writeBytes("echo " + 176 + " > /sys/class/gpio/export\n");

Config the gpio(GPIOH5) as high level output

os.writeBytes("echo out > /sys/class/gpio/gpio" + 176 + "/direction\n");
os.writeBytes("echo 1 > /sys/class/gpio/gpio" + 176 + "/value\n");

Config the gpio(GPIOH5) as input

os.writeBytes("echo in > /sys/class/gpio/gpio" + 176 + "/direction\n");

Get the gpio(GPIOH5) level

Runtime runtime = Runtime.getRuntime(); 
Process process = runtime.exec("cat " + "/sys/class/gpio/gpio" + 176 + "/value");  
InputStream is = process.getInputStream(); 
InputStreamReader isr = new InputStreamReader(is); 
BufferedReader br = new BufferedReader(isr); 
String line ; 
while (null != (line = br.readLine())) { 
 return Integer.parseInt(line.trim()); 
} 

Release the gpio(GPIOH5)

 os.writeBytes("echo " + 176 + " > /sys/class/gpio/unexport\n");

###2. On Ubuntu
####GPIO List

  • Linux-3.14
PIN         GPIO         Number
PIN37       GPIOH5         176
PIN33       GPIOAO6        151
  • Linux-4.9
PIN         GPIO         Number
PIN37       GPIOH5         31
PIN33       GPIOAO6        6

####How to access GPIO on Terminal

[Example on linux-3.14]
Request the gpio(GPIOH5)

$ echo 176 > /sys/class/gpio/export

Config the gpio(GPIOH5) as output

$ echo out > /sys/class/gpio/gpio176/direction

Config the gpio(GPIOH5) as high level output

$ echo 1 >  /sys/class/gpio/gpio176/value

Config the gpio(GPIOH5) as low level output

$ echo 0 >  /sys/class/gpio/gpio176/value

Config the gpio(GPIOH5) as input

$ echo in > /sys/class/gpio/gpio176/direction

Get the level of gpio(GPIOH5)

$ cat  /sys/class/gpio/gpio176/value

Release the gpio(GPIOH5)

$ echo 176 > /sys/class/gpio/unexport

How to use I2C Pin as normal GPIO?
Can Anyone explaine the VIM GPIO Pinout can it use them as Arduino or Respberry Pi do some projects
#2

@terry
Hi, I’m running 20180209 firmware
ADB part is able to control GPIO but while I write an app to control it following your example I got errors and GPIO unchanged.

even I download apk from https://github.com/terry2droid/Wiringpi , that GPIO still unable to change.

The error is : java.io.IOException: stream closed

Is there any steps I need to do??

Thanks.