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Rpi2 LED control

Posted: Fri Feb 06, 2015 3:41 pm
by rahlquist
Ok so far Dom has been a gem and given me this much info.

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#act off
echo none | sudo tee /sys/class/leds/led0/trigger

#pwr off
echo 35  | sudo tee /sys/class/gpio/export
echo out | sudo tee /sys/class/gpio/gpio35/direction
echo 0   | sudo tee /sys/class/gpio/gpio35/value

#act on
echo mmc0 | sudo tee /sys/class/leds/led0/trigger

#pwr on
echo 35  | sudo tee /sys/class/gpio/export
echo in  | sudo tee /sys/class/gpio/gpio35/direction
I had to update to latest firmware to get the led0 device.

The PWR led does not respond to that pwr on for me. What I have found works is;

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echo 35  | sudo tee /sys/class/gpio/export
echo out  | sudo tee /sys/class/gpio/gpio35/direction
echo 1   | sudo tee /sys/class/gpio/gpio35/value
The above does not stick after a reboot though. During reboot initally both LED work but the power one drops off during this part of the boot(over serial console)

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[    2.501309] Waiting for root device /dev/mmcblk0p2...
[    2.519111] Indeed it is in host mode hprt0 = 00021501
[    2.699025] usb 1-1: new high-speed USB device number 2 using dwc_otg
[    2.707116] Indeed it is in host mode hprt0 = 00001101
[    2.846801] mmc0: host does not support reading read-only switch, assuming write-enable
[    2.860212] mmc0: new high speed SDHC card at address 5379
[    2.867974] mmcblk0: mmc0:5379 SD16G 14.9 GiB
[    2.875763]  mmcblk0: p1 p2
[    2.909340] usb 1-1: New USB device found, idVendor=0424, idProduct=9514
[    2.917645] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.927257] hub 1-1:1.0: USB hub found
[    2.932738] hub 1-1:1.0: 5 ports detected
[    3.068477] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[    3.080003] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
[    3.089832] devtmpfs: mounted
[    3.095239] Freeing unused kernel memory: 396K (80767000 - 807ca000)
[    3.219178] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[    3.339449] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[    3.348290] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    3.360575] smsc95xx v1.0.4
[    3.423233] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-bcm2708_usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:79:0e:11
[    4.156954] udevd[175]: starting version 175
[    4.711666] bcm2708_i2c_init_pinmode(1,2)
[    4.743208] bcm2708_i2c_init_pinmode(1,3)
I moved this troubleshooting out of the other thread as not to clutter it anymore. If any mods want to delete the inital troubleshooting from there please feel free.

Re: Rpi2 LED control

Posted: Fri Feb 06, 2015 6:10 pm
by rpdom
To be able to control the PWR LED you first have to do

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echo 35  | sudo tee /sys/class/gpio/export
echo out | sudo tee /sys/class/gpio/gpio35/direction
The you turn it on with

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echo 1   | sudo tee /sys/class/gpio/gpio35/value

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echo 0   | sudo tee /sys/class/gpio/gpio35/value
and put it back to normal with

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echo in | sudo tee /sys/class/gpio/gpio35/direction
None of that will stick over a reboot.

If the PWR LED is turning off during normal usage then you not enough power is getting to your Pi. You may also see a coloured square in the top right of your screen.

Re: Rpi2 LED control

Posted: Fri Feb 06, 2015 7:05 pm
by rahlquist
rpdom wrote: If the PWR LED is turning off during normal usage then you not enough power is getting to your Pi. You may also see a coloured square in the top right of your screen.
Good info to have. I am running headless so I have no idea about the dot. The adapter I am using is rated at 5V 2A and is putting out 5.18-5.2v and on average 450ma but I have seen it spike as high as 680ma. I get the same behavior on an Anker charger, and powered from my PC's USB over console cable. I have a new 5v 3A buck converter on the way that I will feed from an old 120W laptop power supply. So hopefully that fixes things.

Re: Rpi2 LED control

Posted: Wed Jun 17, 2015 2:28 am
by wilminator
I'm running Jessie (NOOBS Wheezy upgraded to Jessie online) and the commands provided above did not work for me. But this did:

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sudo su
echo 0 >/sys/class/leds/led1/brightness
I tried following but it did not work:

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sudo echo 0 >/sys/class/leds/led1/brightness
echo 0 > sudo tee /sys/class/leds/led1/brightness
I'm hoping to write this into a shutdown script.