Copyright | (c) 2017 Quixoftic LLC |
---|---|
License | BSD3 |
Maintainer | Drew Hess <dhess-src@quixoftic.com> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Basic GPIO types.
- newtype Pin = Pin Int
- data PinInputMode
- data PinOutputMode
- data PinCapabilities = PinCapabilities {}
- data PinDirection
- data PinActiveLevel
- data PinValue
- data PinInterruptMode
- pinNumber :: Pin -> Int
- invertDirection :: PinDirection -> PinDirection
- invertValue :: PinValue -> PinValue
- valueToBool :: PinValue -> Bool
- boolToValue :: Bool -> PinValue
- data SomeGpioException = Exception e => SomeGpioException e
- gpioExceptionToException :: Exception e => e -> SomeException
- gpioExceptionFromException :: Exception e => SomeException -> Maybe e
GPIO pins
A GPIO pin, identified by pin number.
Note that GPIO pin numbering is platform- and runtime-dependent. See the documentation for your particular platform for an explanation of how pin numbers are assigned to physical pins.
data PinInputMode Source #
GPIO pins may support a number of different physical configurations when used as a digital input.
Pins that are capable of input will at least support the
InputDefault
mode. InputDefault
mode is special in that, unlike
the other input modes, it does not represent a unique physical
configuration, but is simply a pseudonym for another (actual) input
mode. Exactly which mode is used by the hardware when
InputDefault
mode is specified is platform-dependent. By using
InputDefaut
mode, you are saying that you don't care about the
pin's actual configuration, other than the fact that it's being
used for input.
InputDefault | The pin's default input mode, i.e., the mode used when a more specific mode is not specified |
InputFloating | A floating / high-impedance / tri-state mode which uses little power, but when disconnected, may cause the pin's value to be indeterminate |
InputPullUp | The pin is connected to an internal pull-up resistor such
that, when the pin is disconnected or connected to a floating /
high-impedance node, its physical value will be |
InputPullDown | The pin is connected to an internal pull-down resistor such
that, when the pin is disconnected or connected to a floating /
high-impedance node, its physical value will be |
data PinOutputMode Source #
GPIO pins may support a number of different physical configurations when used as a digital output.
Pins that are capable of output will at least support the
OutputDefault
mode. OutputDefault
mode is special in that,
unlike the other output modes, it does not represent a unique
physical configuration, but is simply a pseudonym for another
(actual) output mode. Exactly which mode is used by the hardware
when OutputDefault
mode is specified is platform-dependent. By
using OutputDefaut
mode, you are saying that you don't care about
the pin's actual configuration, other than the fact that it's being
used for output.
OutputDefault | The pin's default output mode, i.e., the mode used when a more specific mode is not specified |
OutputPushPull | |
OutputOpenDrain | The output actively drives the |
OutputOpenDrainPullUp | The output actively drives the |
OutputOpenSource | The output actively drives the |
OutputOpenSourcePullDown | The output actively drives the |
data PinCapabilities Source #
Catalog a pin's capabilities.
PinCapabilities | |
|
data PinDirection Source #
A pin's direction (input/output).
data PinActiveLevel Source #
A pin's active level (active-high/active-low).
A pin's signal level as a binary value.
data PinInterruptMode Source #
A pin's interrupt mode.
Note that the pin's interrupt mode is defined in terms of the pin's
logical signal value; i.e., when the pin is configured for
active-low logic, RisingEdge
refers to the physical signal's
trailing edge, and FallingEdge
refers to the physical signal's
rising edge.
Disabled | Interrupts are disabled |
RisingEdge | Interrupt on the pin's (logical) rising edge |
FallingEdge | Interrupt on the pin's (logical) falling edge |
Level | Interrupt on any change to the pin's signal level |
Convenience functions
invertDirection :: PinDirection -> PinDirection Source #
Invert a PinDirection
value.
>>>
invertDirection In
Out>>>
invertDirection Out
In
invertValue :: PinValue -> PinValue Source #
Invert a PinValue
.
>>>
invertValue High
Low>>>
invertValue Low
High
PinValue conversion to/from Bool
valueToBool :: PinValue -> Bool Source #
Convert a PinValue
to its logical boolean equivalent.
>>>
valueToBool High
True>>>
valueToBool Low
False
boolToValue :: Bool -> PinValue Source #
GPIO exceptions
data SomeGpioException Source #
The top level of the GPIO exception hierarchy.
Exception e => SomeGpioException e |
gpioExceptionToException :: Exception e => e -> SomeException Source #
Convert SomeGpioException
to SomeException
.
gpioExceptionFromException :: Exception e => SomeException -> Maybe e Source #
Ask whether an exception is SomeGpioException
.