Accessing GPIO pins

[RickR]

Hello,

 

I have installed ARMBIAN 5.60 stable Debian GNU/Linux 9 (stretch) 4.14.70-sunxi on a Banana Pi M2+ and I need to read and write to the GPIO pins from a bash script, does anyone have a workable solution?

 

I tried with an Orange Pi in the past and I compiled a binary to access the gpio values but it did not work and I cannot find that source any more.

 

Thanks in advance. 

 

[martinayotte]

12 hours ago, RickR said:

I need to read and write to the GPIO pins from a bash script

The simplest way is to use gpio sysfs ...

echo 20 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio20/direction
echo 1 > /sys/class/gpio/gpio20/value

 

[RickR]

On 11/2/2018 at 11:43 PM, martinayotte said:

The simplest way is to use gpio sysfs ...

echo 20 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio20/direction
echo 1 > /sys/class/gpio/gpio20/value

Thank you Martinayotte, I have had limited success with this approach and it requires superuser privileges which makes it a bit risky for me to call from the web server, but then I may be able to work out a secure way to access that interface.  The "gpio" command from the WiringOP github repo seems to be very promising as well.

Thank you Martinayotte, that is very helpful.  The difficulty I found is that it required superuser permissions and I managed to get the gpio utility compiled and finally working late last night and it does not require superuser permissions 

[Levent Erenler]

On 11/2/2018 at 8:43 AM, martinayotte said:

The simplest way is to use gpio sysfs ...

echo 20 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio20/direction
echo 1 > /sys/class/gpio/gpio20/value

 

Hi,I am a developing a c++ application with OPI 0+2 (h5 + mainline kernel), controls a motor with an encoder and a driver. I did it , but it consume to much cpu power (%8) . I could access with using sysfs and character device. Both of them works like open->read->close .Actually it works very well with polling. Unfortunately consume to much cpu. Interrupt freq around 6600hz (150 us) . Is there anyway to control interrupt with dev mem? Or could anyone give me a startup point to access (c++) gpio interrupts efficiently. Btw i tyied libgpiod based on character device. Thank you.

[Tido]

1 hour ago, Levent Erenler said:

Or could anyone give me a startup point to access (c++) gpio interrupts efficiently.

 ArmbianIO API - in C
https://forum.armbian.com/topic/5655-armbianio-api-proposal/

 

 User Space IO - is Python 3 and Java 8 bindings for user space GPIO, SPI, I2C, PWM and Serial interfaces
https://forum.armbian.com/topic/6523-user-space-io-is-python-3-and-java-8-bindings-for-user-space-gpio-spi-i2c-pwm-and-serial-interfaces/ and his improvement: https://github.com/sgjava/java-periphery

 

 pyGPIO - A 'more general' python GPIO library based on pyA20
https://forum.armbian.com/topic/5662-pygpio-a-more-general-python-gpio-library

 

[Levent Erenler]

1 hour ago, Tido said:

 ArmbianIO API - in C
https://forum.armbian.com/topic/5655-armbianio-api-proposal/

 pyGPIO - A 'more general' python GPIO library based on pyA20
https://forum.armbian.com/topic/5662-pygpio-a-more-general-python-gpio-library

 

Thanks for your answer, i checked ArmbianIO, it is based on sysfs.

pyGPIO is based on dev/mem, this is what i am looking unfortunatelly it does not support interrupts. I could not find a way to get gpio int from memory.

thank you.

[Kovács Gábor]

Hello RickR,

 

Could you pplease share how you managed to compile it? With sources and some basic instructions?

 

Thanks,

 

Gabor

[RickR]

Hello Gabor,

 

Sorry, I do not have a valid Banana Pi platform to test this again as this project was done many years ago.  If I do get a chance to test the compilation once again I shall send you the details.

 

Best of luck,

 

Rick