Blinky and Button examples using Python
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== Button Example== | == Button Example== | ||
| + | In Electrum100, GPIO PA31 is used for the user Button. | ||
import sys | import sys | ||
import time | import time | ||
Revision as of 17:15, 3 August 2010
Contents |
Examples using Python
The following application note covers the use of Electrum100's peripherals using Python. SYSFS method is used to access the GPIO's. To create the interfaces for GPIO's under /sys/class/gpio/*, the following configuration has to be enabled in the board configuration file
CONFIG_GPIO_SYSFS=Y
Blinky Example
User LED is connected to GPIO PA30. An interface for the user LED is created in the kernel by adding the following code in board-electrum-100.c
/*
* LEDs
*/
static struct gpio_led ek_leds[] = {
{ /* led1, yellow */
.name = "ds1",
.gpio = AT91_PIN_PA25,
.default_trigger = "heartbeat",
},
{ /* led2, green */
.name = "ds2",
.gpio = AT91_PIN_PA30,
//.active_low = 1,
.default_trigger = "none",
}
};
And add the following lines in ek_board_init()
/* LEDs */ at91_gpio_leds(ek_leds, ARRAY_SIZE(ek_leds));
Python script for Blinky Example:
import sys
import time
print "Blinking User LED"
print "Enter CTRL+C to exit"
def ledon():
value = open("/sys/class/leds/ds2/brightness","w")
value.write(str(1))
value.close()
def ledoff():
value = open("/sys/class/leds/ds2/brightness","w")
value.write(str(0))
value.close()
while True:
ledon()
time.sleep(.5)
ledoff()
time.sleep(.5)
Button Example
In Electrum100, GPIO PA31 is used for the user Button.
import sys
import time
print "Button Example"
print "Press CTRL + C to exit"
def pins_export():
try:
pin1export = open("/sys/class/gpio/export","w")
pin1export.write(str(63))
pin1export.close()
except IOError:
print "INFO: GPIO 63 already Exists, skipping export gpio"
def read_button():
fp1 = open("/sys/class/gpio/gpio63/value","r")
value = fp1.read()
return value
fp1.close()
def write_led(value):
fp2 = open("/sys/class/leds/ds2/brightness","w")
fp2.write(str(value))
fp2.close()
pins_export()
while True:
button_value = read_button()
write_led(button_value)