osd-contiki/dev/arduino/arduino-compat.h

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/*
* Copyright (c) 2014-15, Ralf Schlatterbeck Open Source Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*/
/**
* \defgroup Hardware independent Arduino compatibility
*
* This file is meant to be included into a compatible Arduino.h
*
* Arduino calls the combination of an AVR timer and the corresponding
* channel a timer. So Arduinos definition of timer is different from
* that of AVR documentation. Arduino defines arbitrary TIMERXX macros
* that are later parsed in a big switch statement.
*
* We use a better representation of timer values than arduino here:
* The AVRs have max. 6 (numbered 0-5) timers. For representing these we
* need 3 bits. In addition each timer can have channels A-D (or just
* one channel in which case there is no alphabetic suffix). We can
* represent this in 2 bits. We add one bit to each for future
* compatibility and come up with 7 bits, still easily represented in 8
* bit with room for a 'NOT_ON_TIMER' value. From these we can easily
* compute the channel and timer by shifting. No need for a big switch
* statement, and -- which is the common case -- when initializing with
* a constant for the pin, the compiler can compute everything at
* compile-time (that's why the analogWrite below is implemented as a
* static inline function).
*
* Note that Arduino also defines some TIMERX without an alphabetic
* suffix (e.g. TIMER2). I suspect this is for microcontrollers that
* only have one channel for a certain timer. So this is currently
* defined the same as TIMER2A because they are never used together.
* This may be wrong and may be a bug.
*
* Note that the hardware definition still has to define a
* digitalPinToTimer macro. We suggest to not implement this with a
* static table in program memory (as currently done by arduino) but
* instead as an if-cascade (as a C-macro). This allows the compiler to
* completely compute the if-cascade at compile-time if the used pin is
* a constant, resulting in *much* smaller code-footprint in the most
* common use-case.
*
* @{
*/
/**
* \file
* Header file for arduino compatibility
* \author
* Ralf Schlatterbeck <rsc@runtux.com>
*
*/
/* To be included by a compatible Arduino.h */
#ifdef __cplusplus
extern "C" {
#endif
#include "contiki.h"
#include "hw_timer.h"
#include "adc.h"
#ifdef __cplusplus
} // extern "C"
#endif
#define HW_TIMER_SHIFT 3
#define NOT_ON_TIMER 0xFF
#define TIMER0A ((0 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER0B ((0 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER1A ((1 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER1B ((1 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER1C ((1 << HW_TIMER_SHIFT) | HWT_CHANNEL_C)
#define TIMER2 ((2 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER2A ((2 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER2B ((2 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER3A ((3 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER3B ((3 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER3C ((3 << HW_TIMER_SHIFT) | HWT_CHANNEL_C)
#define TIMER4A ((4 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER4B ((4 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER4C ((4 << HW_TIMER_SHIFT) | HWT_CHANNEL_C)
#define TIMER4D ((4 << HW_TIMER_SHIFT) | HWT_CHANNEL_D)
#define TIMER5A ((5 << HW_TIMER_SHIFT) | HWT_CHANNEL_A)
#define TIMER5B ((5 << HW_TIMER_SHIFT) | HWT_CHANNEL_B)
#define TIMER5C ((5 << HW_TIMER_SHIFT) | HWT_CHANNEL_C)
#ifdef __cplusplus
extern "C" {
#endif
static inline void analogWrite(uint8_t pin, int val)
{
/*
* Note on the timer usage: Arduino has code here that
* explicitly checks if the given val is 0 or 0xFF.
* The 16-bit timers on Arduino use the phase correct PWM
* waveform generation mode which already sets the output to
* continuous low for 0 or continuous high for 0xFF. When using
* an 8-bit timer, Arduino uses fast PWM which creates a tiny
* spike for 0, so to be Arduino-compatible in this mode we use
* digitalWrite in this case.
*/
uint8_t arduino_timer = digitalPinToTimer(pin);
pinMode(pin, OUTPUT);
if (val == 0 || arduino_timer == NOT_ON_TIMER) {
digitalWrite(pin, (val < 128) ? LOW : HIGH);
} else {
uint8_t t = arduino_timer >> HW_TIMER_SHIFT;
uint8_t c = arduino_timer & HWT_CHANNEL_MASK;
hwtimer_pwm_enable (t, c);
hwtimer_set_pwm (t, c, val);
}
}
/*
* turnOffPWM of arduino is implemented by hw_timer
*/
#define turnOffPWM(atimer) \
( (atimer) == NOT_ON_TIMER \
? (void)0 \
: (void)hwtimer_pwm_disable \
(atimer >> HW_TIMER_SHIFT, atimer & HWT_CHANNEL_MASK) \
)
/*
* micros on arduino takes timer overflows into account.
* We put in the seconds counter. To get a consistent seconds / ticks
* value we have to disable interrupts.
*/
static inline uint32_t micros (void)
{
uint32_t ticks;
uint8_t sreg = SREG;
cli ();
ticks = clock_seconds () * 1000000L
+ clock_time () * 1000L / CLOCK_SECOND;
SREG = sreg;
return ticks;
}
/*
* millis counts only internal timer ticks since start, not trying to do
* something about overflows. Note that we don't try to emulate overflow
* behaviour of arduino implementation.
*/
#define millis() (((uint32_t)clock_time())*1000L/CLOCK_SECOND)
#define delay(ms) clock_delay_msec(ms)
#define delayMicroseconds(us) clock_delay_usec(us)
#define analogRead(analogpin) readADC(analogpin)
#ifdef __cplusplus
} // extern "C"
#endif
/*
* VI settings, see coding style
* ex:ts=8:et:sw=2
*/
/** @} */