-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Access GPIO pins on Raspberry Pi via wiringPi library
--   
--   This is a Haskell binding to the <a>wiringPi library</a>, which allows
--   you to interface with the GPIO pins on the <a>Raspberry Pi</a>. Unlike
--   some other solutions for using the Raspberry Pi's GPIO pins, wiringPi
--   provides access to more advanced features, such as enabling the
--   internal pull-up or pull-down resistors.
@package wiringPi
@version 1.0.1


-- | This is a Haskell binding to the <a>wiringPi library</a>. The
--   functions here (mostly) correspond directly to the functions in the C
--   library, except for how initialization and pin numbering are handled.
--   To use this library, you must either run as root, or set the
--   <tt>WIRINGPI_GPIOMEM</tt> environment variable. However, if you set
--   <tt>WIRINGPI_GPIOMEM</tt>, then <a>PWM does not work</a>, so to use
--   PWM you must be root.
module System.Hardware.WiringPi

-- | Represents a <a>pin number</a>. The constructor determines which one
--   of the three pin numbering schemes is used. See <a>the README</a> for
--   details, and a pretty picture. <a>==</a> returns true for the same
--   physical pin, even if different pin numbering schemes are used.
data Pin

-- | use <a>wiringPi pin number</a>
Wpi :: Int -> Pin

-- | use BCM_GPIO numbering (these are the numbers on the <a>Adafruit
--   cobbler</a> and on <a>pinout.xyz</a>).
Gpio :: Int -> Pin

-- | use physical pin numbers on P1 connector
Phys :: Int -> Pin

-- | Digital logic level.
data Value
LOW :: Value
HIGH :: Value

-- | Pin mode, used with <tt>pinMode</tt>.
data Mode

-- | digital input
INPUT :: Mode

-- | digital output
OUTPUT :: Mode

-- | pulse-width modulation; only supported on wiringPi pins 1, 23, 24, and
--   26
PWM_OUTPUT :: Mode

-- | <a>clock output</a>; only supported on wiringPi pins 7, 21, 22, and 29
GPIO_CLOCK :: Mode

-- | Use with <tt>pullUpDnControl</tt> to enable internal pull-up or
--   pull-down resistor.
data Pud

-- | disable pull-up/pull-down
PUD_OFF :: Pud

-- | enable pull-down resistor
PUD_DOWN :: Pud

-- | enable pull-up resistor
PUD_UP :: Pud

-- | Argument to <tt>pwmSetMode</tt> to set "balanced" mode or "mark-space"
--   mode.
data PwmMode

-- | balanced mode
PWM_MODE_BAL :: PwmMode

-- | mark-space mode
PWM_MODE_MS :: PwmMode

-- | Interrupt levels, used with <tt>wiringPiISR</tt>.
data IntEdge

-- | no initialization of the pin will happen
INT_EDGE_SETUP :: IntEdge

-- | interrupt on a falling edge of the incoming signal
INT_EDGE_FALLING :: IntEdge

-- | interrupt on a rising edge of the incoming signal
INT_EDGE_RISING :: IntEdge

-- | interrupt on both rising edge and falling edge of the incoming signal
INT_EDGE_BOTH :: IntEdge

-- | Value used with <a>pwmWrite</a>. Typically ranges from 0-1024, but the
--   range can be increased up to 4096 by calling <a>pwmSetRange</a>.
type PwmValue = Word16

-- | Initialize the wiringPi library. This is optional, because it will
--   automatically be called on the first use of a wiringPi function.
--   Raises an exception if the underlying C function returns an error
--   code. However, in practice, the C function <tt>wiringPiSetupGpio</tt>
--   terminates the program on error. Setting the environment variable
--   <tt>WIRINGPI_CODES</tt> is supposed to change this behavior, but in my
--   experience it doesn't, and the program is still terminated on error.
wiringPiSetupGpio :: IO ()
pinMode :: Pin -> Mode -> IO ()
pullUpDnControl :: Pin -> Pud -> IO ()
digitalRead :: Pin -> IO Value
digitalWrite :: Pin -> Value -> IO ()

-- | Default range is 0-1024, but it can be changed with
--   <a>pwmSetRange</a>.
pwmWrite :: Pin -> PwmValue -> IO ()

-- | Write 8 bits to the 8 pins that have wiringPi pin numbers 0-7.
digitalWriteByte :: Word8 -> IO ()
pwmSetMode :: PwmMode -> IO ()

-- | Change the range used by <a>pwmWrite</a>. Default is 1024. <a>Maxium
--   is 4096</a>.
pwmSetRange :: PwmValue -> IO ()

-- | Change the PWM divisor. Range is <a>2-4095</a>.
pwmSetClock :: PwmValue -> IO ()

-- | Returns 1 for very early Rasbperry Pis and 2 for all others. This
--   distinction is because at some point early on, the Raspberry Pi
--   foundation replaced BCM_GPIO 0, 1, and 21 with BCM_GPIO 2, 3, and 27
--   at the same places on the P1 connector. Also, the user-accessible I²C
--   bus changed from bus 0 to bus 1.
piGpioLayout :: IO Int

-- | An alias for <a>piGpioLayout</a>. (The wiringPi C library changed the
--   name from <tt>piBoardRev</tt> to <tt>piGpioLayout</tt> in version
--   2.36, and really <tt>piGpioLayout</tt> is a much better name for it.)
piBoardRev :: IO Int

-- | Converts a pin to its "Broadcom GPIO" number. (In other words, the pin
--   number that would be specified with the <a>Gpio</a> constructor.) This
--   relies on <a>unsafePerformIO</a> internally, because the pin mapping
--   depends on the board revision. Returns <a>Nothing</a> if the pin
--   number is invalid; e. g. it is out of range or is a power or ground
--   pin on the physical connector. See <a>the pretty picture</a> for
--   details. (The picture depicts the mapping when <a>piGpioLayout</a> is
--   2; there is a slightly different mapping when <a>piGpioLayout</a> is
--   1.)
pinToBcmGpio :: Pin -> Maybe Int

-- | Sets up an interrupt handler for the specified pin. When the pin
--   transitions as specified by <a>IntEdge</a>, the IO action will be
--   executed. Be aware that if interrupts come quickly enough, the IO
--   action might only be called once when the pin has transitioned more
--   than once. If your program uses this function, you must link with
--   <tt>-threaded</tt>, or deadlock may occur. You should only call
--   <tt>wiringPiISR</tt> once per pin, because the underlying C library
--   does not support changing or removing an interrupt handler once it has
--   been added.
wiringPiISR :: Pin -> IntEdge -> IO () -> IO ()
instance GHC.Read.Read System.Hardware.WiringPi.Pin
instance GHC.Show.Show System.Hardware.WiringPi.Pin
instance GHC.Classes.Ord System.Hardware.WiringPi.Pin
instance GHC.Classes.Eq System.Hardware.WiringPi.Pin