Table 10.2. trigger Configuration
Configuration
Description
none
No trigger is set.
mmc0
LED acts as microSD card access lamp.
timer
Blink on and off at certain intervals. After setting this trigger, delay_on and delay_off files appear under the LED class directory
which can be used to set the on and off times in millisecond increments.
heartbeat
Blink on and off like a heart beat.
default-on
Used mainly from the kernel. The LED is turned on at boot time.
Executing the commands below will cause LED3 to repeatedly turn on for 1 second and then off for 500 milliseconds.
[armadillo ~]# echo timer > /sys/class/leds/red/trigger
[armadillo ~]# echo 1000 > /sys/class/leds/red/delay_on
[armadillo ~]# echo 500 > /sys/class/leds/red/delay_off
Figure 10.4. Specifying timer as Trigger for LED3
The current trigger of the LED can be obtained by reading the trigger file. The value enclosed in [] is the current trigger.
[armadillo ~]# cat /sys/class/leds/yellow/trigger
[none] mmc0 timer heartbeat default-on
Figure 10.5. Displaying LED3 Timer
10.2. GPIO
The Armadillo-400 Series GPIO are supported as GPIO class devices. The GPIO can be controlled with the files under
the GPIO class directories. For the GPIO class directories and corresponding GPIO, refer to Table 10.3, “GPIO and GPIO
Class Directories”.
Table 10.3. GPIO and GPIO Class Directories
GPIO Class Directory
Description
/sys/class/gpio/CON9_1/
CON9 pin 1
/sys/class/gpio/CON9_2/
CON9 pin 2
/sys/class/gpio/CON9_11/
CON9 pin 11
/sys/class/gpio/CON9_12/
CON9 pin 12
/sys/class/gpio/CON9_13/
CON9 pin 13
/sys/class/gpio/CON9_14/
CON9 pin 14
/sys/class/gpio/CON9_15/
CON9 pin 15
/sys/class/gpio/CON9_16/
CON9 pin 16
/sys/class/gpio/CON9_17/
CON9 pin 17
/sys/class/gpio/CON9_18/
CON9 pin 18
/sys/class/gpio/CON9_21/
CON9 pin 21
/sys/class/gpio/CON9_22/
CON9 pin 22
/sys/class/gpio/CON9_23/
CON9 pin 23
/sys/class/gpio/CON9_24/
CON9 pin 24
/sys/class/gpio/CON9_25/
CON9 pin 25
/sys/class/gpio/CON9_26/
CON9 pin 26
/sys/class/gpio/CON9_27/
CON9 pin 27
/sys/class/gpio/CON9_28/
CON9 pin 28
Armadillo-440 LCD Model Development Set Startup Guide
Other Devices
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