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Diffstat (limited to 'wirish/include/wirish/io.h')
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diff --git a/wirish/include/wirish/io.h b/wirish/include/wirish/io.h new file mode 100644 index 0000000..de56a49 --- /dev/null +++ b/wirish/include/wirish/io.h @@ -0,0 +1,222 @@ +/****************************************************************************** + * The MIT License + * + * Copyright (c) 2010 Perry Hung. + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, + * modify, merge, publish, distribute, sublicense, and/or sell copies + * of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + *****************************************************************************/ + +/** + * @file io.h + * + * @brief Arduino-compatible digital pin I/O interface. + */ + +#ifndef _WIRISH_IO_H_ +#define _WIRISH_IO_H_ + +#include <libmaple/libmaple_types.h> +#include <wirish/boards.h> + +/** + * Specifies a GPIO pin behavior. + * @see pinMode() + */ +typedef enum WiringPinMode { + OUTPUT, /**< Basic digital output: when the pin is HIGH, the + voltage is held at +3.3v (Vcc) and when it is LOW, it + is pulled down to ground. */ + + OUTPUT_OPEN_DRAIN, /**< In open drain mode, the pin indicates + "low" by accepting current flow to ground + and "high" by providing increased + impedance. An example use would be to + connect a pin to a bus line (which is pulled + up to a positive voltage by a separate + supply through a large resistor). When the + pin is high, not much current flows through + to ground and the line stays at positive + voltage; when the pin is low, the bus + "drains" to ground with a small amount of + current constantly flowing through the large + resistor from the external supply. In this + mode, no current is ever actually sourced + from the pin. */ + + INPUT, /**< Basic digital input. The pin voltage is sampled; when + it is closer to 3.3v (Vcc) the pin status is high, and + when it is closer to 0v (ground) it is low. If no + external circuit is pulling the pin voltage to high or + low, it will tend to randomly oscillate and be very + sensitive to noise (e.g., a breath of air across the pin + might cause the state to flip). */ + + INPUT_ANALOG, /**< This is a special mode for when the pin will be + used for analog (not digital) reads. Enables ADC + conversion to be performed on the voltage at the + pin. */ + + INPUT_PULLUP, /**< The state of the pin in this mode is reported + the same way as with INPUT, but the pin voltage + is gently "pulled up" towards +3.3v. This means + the state will be high unless an external device + is specifically pulling the pin down to ground, + in which case the "gentle" pull up will not + affect the state of the input. */ + + INPUT_PULLDOWN, /**< The state of the pin in this mode is reported + the same way as with INPUT, but the pin voltage + is gently "pulled down" towards 0v. This means + the state will be low unless an external device + is specifically pulling the pin up to 3.3v, in + which case the "gentle" pull down will not + affect the state of the input. */ + + INPUT_FLOATING, /**< Synonym for INPUT. */ + + PWM, /**< This is a special mode for when the pin will be used for + PWM output (a special case of digital output). */ + + PWM_OPEN_DRAIN, /**< Like PWM, except that instead of alternating + cycles of LOW and HIGH, the voltage on the pin + consists of alternating cycles of LOW and + floating (disconnected). */ +} WiringPinMode; + +/** + * Configure behavior of a GPIO pin. + * + * @param pin Number of pin to configure. + * @param mode Mode corresponding to desired pin behavior. + * @see WiringPinMode + */ +void pinMode(uint8 pin, WiringPinMode mode); + +#define HIGH 0x1 +#define LOW 0x0 + +/** + * Writes a (digital) value to a pin. The pin must have its + * mode set to OUTPUT or OUTPUT_OPEN_DRAIN. + * + * @param pin Pin to write to. + * @param value Either LOW (write a 0) or HIGH (write a 1). + * @see pinMode() + */ +void digitalWrite(uint8 pin, uint8 value); + +/** + * Read a digital value from a pin. The pin must have its mode set to + * one of INPUT, INPUT_PULLUP, and INPUT_PULLDOWN. + * + * @param pin Pin to read from. + * @return LOW or HIGH. + * @see pinMode() + */ +uint32 digitalRead(uint8 pin); + +/** + * Read an analog value from pin. This function blocks during ADC + * conversion, and has 12 bits of resolution. The pin must have its + * mode set to INPUT_ANALOG. + * + * @param pin Pin to read from. + * @return Converted voltage, in the range 0--4095, (i.e. a 12-bit ADC + * conversion). + * @see pinMode() + */ +uint16 analogRead(uint8 pin); + +/** + * Toggles the digital value at the given pin. + * + * The pin must have its mode set to OUTPUT. + * + * @param pin the pin to toggle. If the pin is HIGH, set it LOW. If + * it is LOW, set it HIGH. + * + * @see pinMode() + */ +void togglePin(uint8 pin); + +/** + * Toggle the LED. + * + * If the LED is on, turn it off. If it is off, turn it on. + * + * The LED must its mode set to OUTPUT. This can be accomplished + * portably over all LeafLabs boards by calling pinMode(BOARD_LED_PIN, + * OUTPUT) before calling this function. + * + * @see pinMode() + */ +static inline void toggleLED() { + togglePin(BOARD_LED_PIN); +} + +/** + * If the button is currently pressed, waits until the button is no + * longer being pressed, and returns true. Otherwise, returns false. + * + * The button pin must have its mode set to INPUT. This can be + * accomplished portably over all LeafLabs boards by calling + * pinMode(BOARD_BUTTON_PIN, INPUT). + * + * @see pinMode() + */ +uint8 isButtonPressed(); + +/** + * Wait until the button is pressed and released, timing out if no + * press occurs. + * + * The button pin must have its mode set to INPUT. This can be + * accomplished portably over all LeafLabs boards by calling + * pinMode(BOARD_BUTTON_PIN, INPUT). + * + * @param timeout_millis Number of milliseconds to wait until the + * button is pressed. If timeout_millis is left out (or 0), wait + * forever. + * + * @return true, if the button was pressed; false, if the timeout was + * reached. + * + * @see pinMode() + */ +uint8 waitForButtonPress(uint32 timeout_millis=0); + +/** + * Shift out a byte of data, one bit at a time. + * + * This function starts at either the most significant or least + * significant bit in a byte value, and shifts out each byte in order + * onto a data pin. After each bit is written to the data pin, a + * separate clock pin is pulsed to indicate that the new bit is + * available. + * + * @param dataPin Pin to shift data out on + * @param clockPin Pin to pulse after each bit is shifted out + * @param bitOrder Either MSBFIRST (big-endian) or LSBFIRST (little-endian). + * @param value Value to shift out + */ +void shiftOut(uint8 dataPin, uint8 clockPin, uint8 bitOrder, uint8 value); + +#endif |