Trigger LED on Orange PI Zero Plus

[reptile]

Hi All,

 

Its been a week learning, battling and reading posts on armbian forum which was very much helpful -  i now starting to master orange pi and armbian!

 

However i can't seem to understand how to trigger the two on board LEDs (Red & Green), in one of the armbian images i tested this was implemented but not in the armbian version suggested for he Orange PI Zero Plus 2 H5: https://www.armbian.com/orange-pi-zero-2-h5/

 

It seems that my leds folder is empty, where to download or how to populate the missing files?

ls /sys/class/leds
Empty folder

uname -r
4.14.4-sunxi64

modprobe gpio-sunxi
modprobe: FATAL: Module gpio-sunxi not found in directory /lib/modules/4.14.4-sunxi64

ls /sys/class/gpio
export  gpiochip0  gpiochip352  unexport

ls /sys/class
backlight  devcoredump    drm       hidraw       ieee80211  mdio_bus  mtd           pps  regulator    scsi_disk     spi_master  udc           watchdog
bdi        devfreq        extcon    hwmon        input      mem       net           ptp  rfkill       scsi_generic  spi_slave   vc            zram-control
block      devfreq-event  gpio      i2c-adapter  iommu      misc      phy           pwm  rtc          scsi_host     thermal     virtio-ports
bsg        dma            graphics  i2c-dev      leds       mmc_host  power_supply  rc   scsi_device  sound         tty         vtconsole

 

Many thanks!

[reptile]

ok, 2nd day and starting to better understand this, will explain it loudly for myself and anyone else:

 

Though the answer was there from the beginning, too bad that it wasn't clear for meL

http://linux-sunxi.org/GPIO

 

First we need to "create" or "attach" the GPIO port using this command:

 

sudo echo XX > /sys/class/gpio/export

The XX is a complex calculation of the GPIO:

 

On 6/25/2016 at 8:04 PM, martinayotte said:

(position of letter in alphabet - 1) * 32 + pin number

 

so for Orange PI Zero plus 2 H5 (should be same for h3/h2) the RED led would on GPIO PA17 and GREEN LED on GPIO PL10  (Info from here: http://linux-sunxi.org/Xunlong_Orange_Pi_Zero_Plus_2 )

The calculation would be (Letter A is 1, the "P" not counted): (1 -0) * 32 + 17 =  17  (For RED LED) while for Green LED: (12 - 1) * 32 + 10 = 362

 

sudo echo 362 > /sys/class/gpio/export
sudo echo 17 > /sys/class/gpio/export

 

Now lets check the status of the GPIOs:

 

cat /sys/kernel/debug/gpio

gpiochip1: GPIOs 0-223, parent: platform/1c20800.pinctrl, 1c20800.pinctrl:
 gpio-9   (                    |reset               ) out hi    
 gpio-14  (                    |sysfs               ) out hi    
 gpio-17  (                    |sysfs               ) in  lo    
 gpio-110 (                    |sysfs               ) in  lo    
 gpio-166 (                    |cd                  ) in  hi IRQ
 gpio-204 (                    |usb0_id_det         ) in  lo IRQ

gpiochip0: GPIOs 352-383, parent: platform/1f02c00.pinctrl, 1f02c00.pinctrl:
 gpio-358 (                    |?                   ) out lo    
 gpio-362 (                    |sysfs               ) in  lo   

 

The GPIOs should be "out" direction (i guess because we are outputting to it), so lets fix them:

sudo echo out > /sys/class/gpio/gpio362/direction
sudo echo out > /sys/class/gpio/gpio17/direction

 

Now that the direction is correct, lets try to switch them on or off:

sudo echo 1 > /sys/class/gpio/gpio362/value
sudo echo 0 > /sys/class/gpio/gpio362/value

sudo echo 1 > /sys/class/gpio/gpio17/value
sudo echo 0 > /sys/class/gpio/gpio17/value

 

Now that the LEDs are controllable, The  next challenge would be adding some rhythm to the led per hardware occasions such as heart beet, read/write..  i hope it will be easier than above

[chwe]

do you want to control the GPIO from console/bash? Or is something like c/python more familiar to you? In case you wanna go for:

 

C @Larry Bank has a nice project for you... 

In case you're more the python guy... (but then you've to write a mapping.h for your board, doesn't need that much time...)

 

[reptile]

I thought to use in few scenarios:

-Slow Blink red on boot until rc.local

-Steady or Fast red blink in rc.local depend on network connection status

-Green blink in python script when all is working

 

I'm not sure how to do it on boot, but my starting point is the simple shell echo command that i could use in rc.local and python using the line: os.system('echo 1 > /sys/class/gpio/gpio362/value')

then somehow to blink it like in arduino

Though it just seem too easy and good to be true, so I'm looking around for some more complex examples of blink and "direct access" to GPIOs from python

 

Thanks for the links, i think the pyGPIO could be my neat start to blink led in python.

 

 

 

 

 

[martinayotte]

11 hours ago, reptile said:

The XX is a complex calculation of the GPIO

That isn't so omplex ...

[chwe]

14 hours ago, reptile said:

Thanks for the links, i think the pyGPIO could be my neat start to blink led in python.

https://github.com/chwe17/pyGPIO/blob/master/pyGPIO/gpio/mapping/template26.h there's your template.. you have to look into the schematics and fill it with the right numbers.. e.g. PH17, PA8 etc... 

Only 

Quote

{ "GPIO2", SUNXI_GPX(Z), 3 },

X and Z should be replaced to keep the library consistent... As soon as you send a PR, I'll add the board to the 'supported boards' and you can test it. 

[reptile]

As an update, on OrangePI H5 Zero Plus (the one with the LAN) the LED triggering command is a bit different (though i am using the same OS that was on Zero plus 2)

 

echo 1 > /sys/class/leds/orangepi:green:pwr/brightness
echo 0 > /sys/class/leds/orangepi:green:pwr/brightness

echo 1 > /sys/class/leds/orangepi:red:status/brightness
echo 0 > /sys/class/leds/orangepi:red:status/brightness