GPIO

A class that supports general-purpose digital input/output functionality.
Generally, it is intended for controlling the input or output of a single physical pin.

Class method

GPIO.setmode( pin, params ) -> nil

Specify the physical pin indicated by "pin" and change the mode of the GPIO.
Refer to the constructor for other information.

Example of use:

# Set pin number 1 output.
GPIO.setmode( 1, GPIO::OUT )

# Set B1 pin to input, with internal pull-up. (for PIC, etc.)
GPIO.setmode( "B1", GPIO::IN|GPIO::PULL_UP )

read_at( pin ) -> Integer

Returns the value read from the specified pin as either 0 or 1.
When reading from the pin set for output, if the hardware permits, the actual value should be read and returned instead of the set value.

Example of use:

GPIO.setmode( 1, GPIO::IN )
v1 = GPIO.read_at( 1 )          # read from pin 1.

high_at?( pin ) -> bool

Return true If the value read from the specified pin is high (==1)

Example of use:

if GPIO.high_at?( 1 )

low_at?( pin ) -> bool

If the value loaded from the specified pin is low-level (== 0), return true.

Example of use:

if GPIO.low_at?( 1 )

write_at( pin, integer_data )

Output a value to the specified pin.
The value must be specified as either 0 or 1.
If the data is out of range (i.e. not 0 or 1), a RangeError will occur.

Example of use:

GPIO.setmode( 1, GPIO::OUT )
GPIO.write_at( 1, 0 )      # output zero to pin 1.

Constructor

GPIO.new( pin, params )

Specify the physical pin indicated by the pin and generate a GPIO object.
At the same time, specify a param to indicate the mode, such as input/output direction.
The pin is typically specified as an integer, but other methods (such as "B1" in PIC) may be used.
Although one bit is the basic unit, pin specification that combines multiple bits may be necessary depending on the device.
Use the following constants for param and specify them connected by |.
IN, OUT, or HIGH_Z instruction is mandatory, and an ArgumentError will occur if it is absent.

Constants:

GPIO::IN            # Set as input
GPIO::OUT           # Set as output
GPIO::HIGH_Z        # Set as high impedance
GPIO::PULL_UP       # Enable internal pull-up
GPIO::PULL_DOWN     # Enable internal pull-down
GPIO::OPEN_DRAIN    # Set to open-drain mode

Usage Example

# Set GPIO pin 1 as output.
gpio1 = GPIO.new(1, GPIO::OUT)

# Set B1 pin as input with internal pull-up (for PIC, etc.).
gpio1 = GPIO.new("B1", GPIO::IN|GPIO::PULL_UP)

Instance methods

read() -> Integer

Return the loaded value as 0 or 1.
It can be any integer only when implementing multiple bit processing.
If reading from the pin set for output, the hardware should read and return the actual value if possible, not the set value.

Example of use:

v1 = gpio1.read()

high?() -> bool

If the loaded value is high level (==1), it returns true.

Example of use:

if gpio1.high?()

low?() -> bool

If the loaded value is low-level (==0), return true.

Example of use:

if gpio1.low?()

write( integer_data )

Specify the value to output to the pin as either 0 or 1.
Only in the case of implementation that handles multiple bits collectively, indicate with any integer value.

Example of use:

gpio1.write( 1 )

setmode( param ) -> nil

Change the GPIO mode at any timing.
When IN, OUT, or HIGH_Z is specified while PULL_UP or other settings have already been set, the previous settings will be invalidated.

Example of use:

# Enable internal pullup.
gpio1.setmode( GPIO::PULL_UP )

# Switch to input and enable internal pullup.
gpio1.setmode( GPIO::IN|GPIO::PULL_UP )

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