Difference between revisions of "Rock/LED"
< Rock
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mode: pin mode, valid values: in or out | mode: pin mode, valid values: in or out | ||
''' | ''' | ||
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| − | |||
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with open('/sys/class/gpio/export', 'w') as f: | with open('/sys/class/gpio/export', 'w') as f: | ||
f.write(str(pinnum)) | f.write(str(pinnum)) | ||
Revision as of 02:54, 20 May 2014
The RR has 3 LEDs, green(172), blue(174), red(175). All can be programmable.
Below is program in different languages to flash the green led on RR.
Contents
c
#include <stdio.h>
int main()
{
FILE *fp = fopen("/sys/class/gpio/export", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%d", 175);
fclose(fp);
fp = fopen("/sys/class/gpio/gpio175/direction", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%s", "out");
fclose(fp);
fp = fopen("/sys/class/gpio/gpio175/value", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%d", 1);
}
int main()
{
FILE *fp = fopen("/sys/class/gpio/export", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%d", 175);
fclose(fp);
fp = fopen("/sys/class/gpio/gpio175/direction", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%s", "out");
fclose(fp);
fp = fopen("/sys/class/gpio/gpio175/value", "w");
if( !fp )
{
printf("error open export file");
return 1;
}
fprintf(fp, "%d", 1);
}
python
import time
def initpin(pinnum, mode):
'''
pinnum: pin number, eg. 172, 175 etc.
mode: pin mode, valid values: in or out
'''
with open('/sys/class/gpio/export', 'w') as f:
f.write(str(pinnum))
with open('/sys/class/gpio/gpio' + str(pinnum) + '/direction', 'w') as f:
f.write(str(mode))
def setpin(pinnum, value):
with open('/sys/class/gpio/gpio' + str(pinnum) + '/value', 'w') as f:
f.write(str(value))
if __name__ == '__main__':
initpin(175, 'out')
while True:
setpin(175, 0)
time.sleep(1)
setpin(175, 1)
time.sleep(1)
def initpin(pinnum, mode):
'''
pinnum: pin number, eg. 172, 175 etc.
mode: pin mode, valid values: in or out
'''
with open('/sys/class/gpio/export', 'w') as f:
f.write(str(pinnum))
with open('/sys/class/gpio/gpio' + str(pinnum) + '/direction', 'w') as f:
f.write(str(mode))
def setpin(pinnum, value):
with open('/sys/class/gpio/gpio' + str(pinnum) + '/value', 'w') as f:
f.write(str(value))
if __name__ == '__main__':
initpin(175, 'out')
while True:
setpin(175, 0)
time.sleep(1)
setpin(175, 1)
time.sleep(1)
shell
#!/bin/sh
# enable the gpio 172 -> green led
echo 172 > /sys/class/gpio/export
# set the direction to output
echo "out" > /sys/class/gpio/gpio172/direction
while true;
do
echo 0 > /sys/class/gpio/gpio172/value #led on
sleep 1
echo 1 > /sys/class/gpio/gpio172/value #led off
sleep 1
done
# enable the gpio 172 -> green led
echo 172 > /sys/class/gpio/export
# set the direction to output
echo "out" > /sys/class/gpio/gpio172/direction
while true;
do
echo 0 > /sys/class/gpio/gpio172/value #led on
sleep 1
echo 1 > /sys/class/gpio/gpio172/value #led off
sleep 1
done
LED class and triggers
on radxa-rock/android-kk branch, 3 LEDs are configured as LED class devices. you can control LEDs via /sys/class/leds/.