def test_export(fs):
fs.CreateFile("/sys/class/gpio/export")
export(19)
with open("/sys/class/gpio/export") as fp:
assert fp.read() == "19"
def setup(channel, direction, initial=None):
"""
You need to set up every channel you are using as an input or an output.
:param channel: the channel based on the numbering system you have specified
(:py:attr:`GPIO.BOARD`, :py:attr:`GPIO.BCM` or :py:attr:`GPIO.SUNXI`).
:param direction: whether to treat the GPIO pin as input or output (use only
:py:attr:`GPIO.IN` or :py:attr:`GPIO.OUT`).
:param initial: When supplied and setting up an output pin, resets the pin
to the value given (can be :py:attr:`0` / :py:attr:`GPIO.LOW` /
:py:attr:`False` or :py:attr:`1` / :py:attr:`GPIO.HIGH` / :py:attr:`True`).
To configure a channel as an input:
.. code:: python
GPIO.setup(channel, GPIO.IN)
To set up a channel as an output:
.. code:: python
GPIO.setup(channel, GPIO.OUT)
You can also specify an initial value for your output channel:
.. code:: python
GPIO.setup(channel, GPIO.OUT, initial=GPIO.HIGH)
**Setup more than one channel:**
You can set up more than one channel per call. For example:
.. code:: python
chan_list = [11,12] # add as many channels as you want!
# you can tuples instead i.e.:
# chan_list = (11,12)
GPIO.setup(chan_list, GPIO.OUT)
"""
if _mode is None:
raise RuntimeError("Mode has not been set")
if isinstance(channel, list):
for ch in channel:
setup(ch, direction, initial)
else:
if channel in _exports:
raise RuntimeError("Channel {0} is already configured".format(channel))
pin = get_gpio_pin(_mode, channel)
try:
sysfs.export(pin)
except (OSError, IOError) as e:
if e.errno == 16: # Device or resource busy
if _gpio_warnings:
warnings.warn("This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.", stacklevel=2)
sysfs.unexport(pin)
sysfs.export(pin)
else:
raise e
sysfs.direction(pin, direction)
_exports[channel] = direction
if direction == OUT and initial is not None:
sysfs.output(pin, initial)