gpio test and leds

hidemon

hi guys , has anyone tried the gpio? just to turn on an LED , the instructions for the raspberry pi 2 can fit ?
thank youhttps://www.youtube.com/watch?v=JNqaSLBCYJw

matsumo

i got inspiration for doing my gpio from majsi's Small GPIO lib. i would not recommend driving LED's directly from the GPIO though, like in the video.. in my opinion, you should use a bjt or mosfet.

phreon

You can turn gpio on and off from the command line. The wiringpi examples do not work as wiringpi has not been translated for OPI. To do it from the command line:

sudo echo 1 > /sys/class/gpio_sw/PA1/data

turns on pin 11

sudo echo 0 > /sys/class/gpio_sw/PA1/data

Turns off pin 11
You can also turn on\off the board leds this way. Search the forum. You need to have the sunxi stuff loaded.

phreon

Forgot o mention, you can drive leds directly from the gpio. Use a small resistor in series to limit the current through the led. Works fine.

matsumo

yes you can drive leds directly from the gpio header, and for a test it can be ok (if you know what you are doing!). just saying it is bad practise, you should have a buffer / line driver / transistor..

matsumo

the H3 datasheet says "buffer strength" 20mA. so as long as you select your resistor carefully...

tranki

a) I have  entered "sudo echo 1 > /sys/class/gpio_sw/PA1/data" in terminal and it prompted
orangepi@OrangePI:~$ sudo echo 1 > /sys/class/gpio_sw/PA1/data
bash: /sys/class/gpio_sw/PA1/data: No such file or directory
b) I thought that i could check the result  without connecting led nor resistence by simulating gpio with command "gpio readall"

phreon

Try:

sudo modprobe gpio-sunxi

and then try:

sudo echo 1 > /sys/class/gpio_sw/PA1/data

take a look at:

http://www.orangepi.org/orangepi ... p;extra=&page=1

redo

you can take uln2008, change 12 for 3.3v.

tranki

root@OrangePI:~# modprobe gpio-sunxi
bash: modprobe: command not found
root@OrangePI:~#