164 lines
6.6 KiB
C
164 lines
6.6 KiB
C
/******************************************************************************
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* The MIT License
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*
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* Copyright (c) 2010 Perry Hung.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*****************************************************************************/
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/**
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* @file wirish/include/wirish/io.h
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* @brief Wiring-style pin I/O interface.
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*/
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#ifndef _WIRISH_IO_H_
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#define _WIRISH_IO_H_
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#include <libmaple/libmaple_types.h>
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#include <boards.h>
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/**
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* Specifies a GPIO pin behavior.
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* @see pinMode()
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*/
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typedef enum WiringPinMode {
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OUTPUT, /**< Basic digital output: when the pin is HIGH, the
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voltage is held at +3.3v (Vcc) and when it is LOW, it
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is pulled down to ground. */
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OUTPUT_OPEN_DRAIN, /**< In open drain mode, the pin indicates
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"low" by accepting current flow to ground
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and "high" by providing increased
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impedance. An example use would be to
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connect a pin to a bus line (which is pulled
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up to a positive voltage by a separate
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supply through a large resistor). When the
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pin is high, not much current flows through
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to ground and the line stays at positive
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voltage; when the pin is low, the bus
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"drains" to ground with a small amount of
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current constantly flowing through the large
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resistor from the external supply. In this
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mode, no current is ever actually sourced
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from the pin. */
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INPUT, /**< Basic digital input. The pin voltage is sampled; when
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it is closer to 3.3v (Vcc) the pin status is high, and
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when it is closer to 0v (ground) it is low. If no
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external circuit is pulling the pin voltage to high or
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low, it will tend to randomly oscillate and be very
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sensitive to noise (e.g., a breath of air across the pin
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might cause the state to flip). */
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INPUT_ANALOG, /**< This is a special mode for when the pin will be
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used for analog (not digital) reads. Enables ADC
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conversion to be performed on the voltage at the
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pin. */
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INPUT_PULLUP, /**< The state of the pin in this mode is reported
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the same way as with INPUT, but the pin voltage
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is gently "pulled up" towards +3.3v. This means
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the state will be high unless an external device
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is specifically pulling the pin down to ground,
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in which case the "gentle" pull up will not
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affect the state of the input. */
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INPUT_PULLDOWN, /**< The state of the pin in this mode is reported
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the same way as with INPUT, but the pin voltage
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is gently "pulled down" towards 0v. This means
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the state will be low unless an external device
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is specifically pulling the pin up to 3.3v, in
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which case the "gentle" pull down will not
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affect the state of the input. */
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INPUT_FLOATING, /**< Synonym for INPUT. */
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PWM, /**< This is a special mode for when the pin will be used for
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PWM output (a special case of digital output). */
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PWM_OPEN_DRAIN, /**< Like PWM, except that instead of alternating
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cycles of LOW and HIGH, the voltage on the pin
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consists of alternating cycles of LOW and
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floating (disconnected). */
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} WiringPinMode;
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/**
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* Configure behavior of a GPIO pin.
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*
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* @param pin Number of pin to configure.
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* @param mode Mode corresponding to desired pin behavior.
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* @see WiringPinMode
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*/
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void pinMode(uint8 pin, WiringPinMode mode);
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#define HIGH 0x1
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#define LOW 0x0
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/**
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* Writes a (digital) value to a pin. The pin must have its
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* mode set to OUTPUT or OUTPUT_OPEN_DRAIN.
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*
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* @param pin Pin to write to.
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* @param value Either LOW (write a 0) or HIGH (write a 1).
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* @see pinMode()
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*/
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void digitalWrite(uint8 pin, uint8 value);
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/**
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* Read a digital value from a pin. The pin must have its mode set to
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* one of INPUT, INPUT_PULLUP, and INPUT_PULLDOWN.
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*
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* @param pin Pin to read from.
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* @return LOW or HIGH.
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* @see pinMode()
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*/
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uint32 digitalRead(uint8 pin);
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/**
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* Read an analog value from pin. This function blocks during ADC
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* conversion, and has 12 bits of resolution. The pin must have its
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* mode set to INPUT_ANALOG.
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*
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* @param pin Pin to read from.
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* @return Converted voltage, in the range 0--4095, (i.e. a 12-bit ADC
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* conversion).
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* @see pinMode()
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*/
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uint16 analogRead(uint8 pin);
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/**
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* Shift out a byte of data, one bit at a time.
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*
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* This function starts at either the most significant or least
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* significant bit in a byte value, and shifts out each byte in order
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* onto a data pin. After each bit is written to the data pin, a
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* separate clock pin is pulsed to indicate that the new bit is
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* available.
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*
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* @param dataPin Pin to shift data out on
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* @param clockPin Pin to pulse after each bit is shifted out
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* @param bitOrder Either MSBFIRST (big-endian) or LSBFIRST (little-endian).
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* @param value Value to shift out
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*/
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void shiftOut(uint8 dataPin, uint8 clockPin, uint8 bitOrder, uint8 value);
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#endif
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