path: root/lib/arduino-stub.cpp

/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2013-2018 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of spreadspace avr utils.
 *
 *  spreadspace avr utils is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  spreadspace avr utils is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
 */

#define ARDUINO_MAIN
#include "Arduino.h"

int atexit(void (* /*func*/ )()) { return 0; }

extern "C" {
#include "stdlib.h"

#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

/*
  wiring.c - Partial implementation of the Wiring API for the ATmega8.
  Part of Arduino - http://www.arduino.cc/

  Copyright (c) 2005-2006 David A. Mellis

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA
*/


// the prescaler is set so that timer0 ticks every 64 clock cycles, and the
// the overflow handler is called every 256 ticks.
#define MICROSECONDS_PER_TIMER0_OVERFLOW (clockCyclesToMicroseconds(64 * 256))

// the whole number of milliseconds per timer0 overflow
#define MILLIS_INC (MICROSECONDS_PER_TIMER0_OVERFLOW / 1000)

// the fractional number of milliseconds per timer0 overflow. we shift right
// by three to fit these numbers into a byte. (for the clock speeds we care
// about - 8 and 16 MHz - this doesn't lose precision.)
#define FRACT_INC ((MICROSECONDS_PER_TIMER0_OVERFLOW % 1000) >> 3)
#define FRACT_MAX (1000 >> 3)

volatile unsigned long timer0_overflow_count = 0;
#  if defined(CORE_TEENSY) || defined(TEENSYDUINO)
volatile unsigned long timer0_millis_count;
#    define MS_COUNTER timer0_millis_count
#  else
volatile unsigned long timer0_millis;
#    define MS_COUNTER timer0_millis
#  endif
static unsigned char timer0_fract = 0;

#if defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
ISR(TIM0_OVF_vect)
#else
ISR(TIMER0_OVF_vect)
#endif
{
  // copy these to local variables so they can be stored in registers
  // (volatile variables must be read from memory on every access)
  unsigned long m = MS_COUNTER;
  unsigned char f = timer0_fract;

  m += MILLIS_INC;
  f += FRACT_INC;
  if (f >= FRACT_MAX) {
    f -= FRACT_MAX;
    m += 1;
  }

  timer0_fract = f;
  MS_COUNTER = m;
  timer0_overflow_count++;
}

unsigned long millis()
{
  unsigned long m;
  uint8_t oldSREG = SREG;

  // disable interrupts while we read MS_COUNTER or we might get an
  // inconsistent value (e.g. in the middle of a write to MS_COUNTER)
  cli();
  m = MS_COUNTER;
  SREG = oldSREG;

  return m;
}

unsigned long micros() {
  unsigned long m;
  uint8_t oldSREG = SREG, t;

  cli();
  m = timer0_overflow_count;
#if defined(TCNT0)
  t = TCNT0;
#elif defined(TCNT0L)
  t = TCNT0L;
#else
  #error TIMER 0 not defined
#endif

#ifdef TIFR0
  if ((TIFR0 & _BV(TOV0)) && (t < 255))
    m++;
#else
  if ((TIFR & _BV(TOV0)) && (t < 255))
    m++;
#endif

  SREG = oldSREG;

  return ((m << 8) + t) * (64 / clockCyclesPerMicrosecond());
}

void delay(unsigned long ms)
{
  uint32_t start = micros();

  while (ms > 0) {
    yield();
    while ( ms > 0 && (micros() - start) >= 1000) {
      ms--;
      start += 1000;
    }
  }
}

/* Delay for the given number of microseconds.  Assumes a 1, 8, 12, 16, 20 or 24 MHz clock. */
void delayMicroseconds(unsigned int us)
{
  // call = 4 cycles + 2 to 4 cycles to init us(2 for constant delay, 4 for variable)

  // calling avrlib's delay_us() function with low values (e.g. 1 or
  // 2 microseconds) gives delays longer than desired.
  //delay_us(us);
#if F_CPU >= 24000000L
  // for the 24 MHz clock for the aventurous ones, trying to overclock

  // zero delay fix
  if (!us) return; //  = 3 cycles, (4 when true)

  // the following loop takes a 1/6 of a microsecond (4 cycles)
  // per iteration, so execute it six times for each microsecond of
  // delay requested.
  us *= 6; // x6 us, = 7 cycles

  // account for the time taken in the preceeding commands.
  // we just burned 22 (24) cycles above, remove 5, (5*4=20)
  // us is at least 6 so we can substract 5
  us -= 5; //=2 cycles

#elif F_CPU >= 20000000L
  // for the 20 MHz clock on rare Arduino boards

  // for a one-microsecond delay, simply return.  the overhead
  // of the function call takes 18 (20) cycles, which is 1us
  __asm__ __volatile__ (
    "nop" "\n\t"
    "nop" "\n\t"
    "nop" "\n\t"
    "nop"); //just waiting 4 cycles
  if (us <= 1) return; //  = 3 cycles, (4 when true)

  // the following loop takes a 1/5 of a microsecond (4 cycles)
  // per iteration, so execute it five times for each microsecond of
  // delay requested.
  us = (us << 2) + us; // x5 us, = 7 cycles

  // account for the time taken in the preceeding commands.
  // we just burned 26 (28) cycles above, remove 7, (7*4=28)
  // us is at least 10 so we can substract 7
  us -= 7; // 2 cycles

#elif F_CPU >= 16000000L
  // for the 16 MHz clock on most Arduino boards

  // for a one-microsecond delay, simply return.  the overhead
  // of the function call takes 14 (16) cycles, which is 1us
  if (us <= 1) return; //  = 3 cycles, (4 when true)

  // the following loop takes 1/4 of a microsecond (4 cycles)
  // per iteration, so execute it four times for each microsecond of
  // delay requested.
  us <<= 2; // x4 us, = 4 cycles

  // account for the time taken in the preceeding commands.
  // we just burned 19 (21) cycles above, remove 5, (5*4=20)
  // us is at least 8 so we can substract 5
  us -= 5; // = 2 cycles,

#elif F_CPU >= 12000000L
  // for the 12 MHz clock if somebody is working with USB

  // for a 1 microsecond delay, simply return.  the overhead
  // of the function call takes 14 (16) cycles, which is 1.5us
  if (us <= 1) return; //  = 3 cycles, (4 when true)

  // the following loop takes 1/3 of a microsecond (4 cycles)
  // per iteration, so execute it three times for each microsecond of
  // delay requested.
  us = (us << 1) + us; // x3 us, = 5 cycles

  // account for the time taken in the preceeding commands.
  // we just burned 20 (22) cycles above, remove 5, (5*4=20)
  // us is at least 6 so we can substract 5
  us -= 5; //2 cycles

#elif F_CPU >= 8000000L
  // for the 8 MHz internal clock

  // for a 1 and 2 microsecond delay, simply return.  the overhead
  // of the function call takes 14 (16) cycles, which is 2us
  if (us <= 2) return; //  = 3 cycles, (4 when true)

  // the following loop takes 1/2 of a microsecond (4 cycles)
  // per iteration, so execute it twice for each microsecond of
  // delay requested.
  us <<= 1; //x2 us, = 2 cycles

  // account for the time taken in the preceeding commands.
  // we just burned 17 (19) cycles above, remove 4, (4*4=16)
  // us is at least 6 so we can substract 4
  us -= 4; // = 2 cycles

#else
  // for the 1 MHz internal clock (default settings for common Atmega microcontrollers)

  // the overhead of the function calls is 14 (16) cycles
  if (us <= 16) return; //= 3 cycles, (4 when true)
  if (us <= 25) return; //= 3 cycles, (4 when true), (must be at least 25 if we want to substract 22)

  // compensate for the time taken by the preceeding and next commands (about 22 cycles)
  us -= 22; // = 2 cycles
  // the following loop takes 4 microseconds (4 cycles)
  // per iteration, so execute it us/4 times
  // us is at least 4, divided by 4 gives us 1 (no zero delay bug)
  us >>= 2; // us div 4, = 4 cycles

#endif

  // busy wait
  __asm__ __volatile__ (
    "1: sbiw %0,1" "\n\t" // 2 cycles
    "brne 1b" : "=w" (us) : "0" (us) // 2 cycles
  );
  // return = 4 cycles
}

void init()
{
  // on the ATmega168, timer 0 is also used for fast hardware pwm
  // (using phase-correct PWM would mean that timer 0 overflowed half as often
  // resulting in different millis() behavior on the ATmega8 and ATmega168)
#if defined(TCCR0A) && defined(WGM01)
  sbi(TCCR0A, WGM01);
  sbi(TCCR0A, WGM00);
#endif

  // set timer 0 prescale factor to 64
#if defined(__AVR_ATmega128__)
  // CPU specific: different values for the ATmega128
  sbi(TCCR0, CS02);
#elif defined(TCCR0) && defined(CS01) && defined(CS00)
  // this combination is for the standard atmega8
  sbi(TCCR0, CS01);
  sbi(TCCR0, CS00);
#elif defined(TCCR0B) && defined(CS01) && defined(CS00)
  // this combination is for the standard 168/328/1280/2560
  sbi(TCCR0B, CS01);
  sbi(TCCR0B, CS00);
#elif defined(TCCR0A) && defined(CS01) && defined(CS00)
  // this combination is for the __AVR_ATmega645__ series
  sbi(TCCR0A, CS01);
  sbi(TCCR0A, CS00);
#else
  #error Timer 0 prescale factor 64 not set correctly
#endif

  // enable timer 0 overflow interrupt
#if defined(TIMSK) && defined(TOIE0)
  sbi(TIMSK, TOIE0);
#elif defined(TIMSK0) && defined(TOIE0)
  sbi(TIMSK0, TOIE0);
#else
  #error	Timer 0 overflow interrupt not set correctly
#endif
}

/**
 * Empty yield() hook.
 *
 * This function is intended to be used by library writers to build
 * libraries or sketches that supports cooperative threads.
 *
 * Its defined as a weak symbol and it can be redefined to implement a
 * real cooperative scheduler.
 */
static void __empty() {
  // Empty
}
void yield(void) __attribute__ ((weak, alias("__empty")));

} // extern "C"

void arduino_init(void)
{
  init();
}

// ******************
// this is from Arduino's wiring_digital.cpp

void pinMode(uint8_t pin, uint8_t mode)
{
  uint8_t bit = digitalPinToBitMask(pin);
  uint8_t port = digitalPinToPort(pin);
  volatile uint8_t *reg, *out;

  if (port == NOT_A_PIN) return;

  // JWS: can I let the optimizer do this?
  reg = portModeRegister(port);
  out = portOutputRegister(port);

  if (mode == INPUT) {
    uint8_t oldSREG = SREG;
                cli();
    *reg &= ~bit;
    *out &= ~bit;
    SREG = oldSREG;
  } else if (mode == INPUT_PULLUP) {
    uint8_t oldSREG = SREG;
                cli();
    *reg &= ~bit;
    *out |= bit;
    SREG = oldSREG;
  } else {
    uint8_t oldSREG = SREG;
                cli();
    *reg |= bit;
    SREG = oldSREG;
  }
}

// Forcing this inline keeps the callers from having to push their own stuff
// on the stack. It is a good performance win and only takes 1 more byte per
// user than calling. (It will take more bytes on the 168.)
//
// But shouldn't this be moved into pinMode? Seems silly to check and do on
// each digitalread or write.
//
// Mark Sproul:
// - Removed inline. Save 170 bytes on atmega1280
// - changed to a switch statment; added 32 bytes but much easier to read and maintain.
// - Added more #ifdefs, now compiles for atmega645
//
//static inline void turnOffPWM(uint8_t timer) __attribute__ ((always_inline));
//static inline void turnOffPWM(uint8_t timer)
static void turnOffPWM(uint8_t timer)
{
  switch (timer)
  {
    #if defined(TCCR1A) && defined(COM1A1)
    case TIMER1A:   cbi(TCCR1A, COM1A1);    break;
    #endif
    #if defined(TCCR1A) && defined(COM1B1)
    case TIMER1B:   cbi(TCCR1A, COM1B1);    break;
    #endif
    #if defined(TCCR1A) && defined(COM1C1)
    case TIMER1C:   cbi(TCCR1A, COM1C1);    break;
    #endif

    #if defined(TCCR2) && defined(COM21)
    case  TIMER2:   cbi(TCCR2, COM21);      break;
    #endif

    #if defined(TCCR0A) && defined(COM0A1)
    case  TIMER0A:  cbi(TCCR0A, COM0A1);    break;
    #endif

    #if defined(TCCR0A) && defined(COM0B1)
    case  TIMER0B:  cbi(TCCR0A, COM0B1);    break;
    #endif
    #if defined(TCCR2A) && defined(COM2A1)
    case  TIMER2A:  cbi(TCCR2A, COM2A1);    break;
    #endif
    #if defined(TCCR2A) && defined(COM2B1)
    case  TIMER2B:  cbi(TCCR2A, COM2B1);    break;
    #endif

    #if defined(TCCR3A) && defined(COM3A1)
    case  TIMER3A:  cbi(TCCR3A, COM3A1);    break;
    #endif
    #if defined(TCCR3A) && defined(COM3B1)
    case  TIMER3B:  cbi(TCCR3A, COM3B1);    break;
    #endif
    #if defined(TCCR3A) && defined(COM3C1)
    case  TIMER3C:  cbi(TCCR3A, COM3C1);    break;
    #endif

    #if defined(TCCR4A) && defined(COM4A1)
    case  TIMER4A:  cbi(TCCR4A, COM4A1);    break;
    #endif
    #if defined(TCCR4A) && defined(COM4B1)
    case  TIMER4B:  cbi(TCCR4A, COM4B1);    break;
    #endif
    #if defined(TCCR4A) && defined(COM4C1)
    case  TIMER4C:  cbi(TCCR4A, COM4C1);    break;
    #endif
    #if defined(TCCR4C) && defined(COM4D1)
    case TIMER4D:	cbi(TCCR4C, COM4D1);	break;
    #endif

    #if defined(TCCR5A)
    case  TIMER5A:  cbi(TCCR5A, COM5A1);    break;
    case  TIMER5B:  cbi(TCCR5A, COM5B1);    break;
    case  TIMER5C:  cbi(TCCR5A, COM5C1);    break;
    #endif
  }
}

void digitalWrite(uint8_t pin, uint8_t val)
{
  uint8_t timer = digitalPinToTimer(pin);
  uint8_t bit = digitalPinToBitMask(pin);
  uint8_t port = digitalPinToPort(pin);
  volatile uint8_t *out;

  if (port == NOT_A_PIN) return;

  // If the pin that support PWM output, we need to turn it off
  // before doing a digital write.
  if (timer != NOT_ON_TIMER) turnOffPWM(timer);

  out = portOutputRegister(port);

  uint8_t oldSREG = SREG;
  cli();

  if (val == LOW) {
    *out &= ~bit;
  } else {
    *out |= bit;
  }

  SREG = oldSREG;
}

int digitalRead(uint8_t pin)
{
  uint8_t timer = digitalPinToTimer(pin);
  uint8_t bit = digitalPinToBitMask(pin);
  uint8_t port = digitalPinToPort(pin);

  if (port == NOT_A_PIN) return LOW;

  // If the pin that support PWM output, we need to turn it off
  // before getting a digital reading.
  if (timer != NOT_ON_TIMER) turnOffPWM(timer);

  if (*portInputRegister(port) & bit) return HIGH;
  return LOW;
}

// ******************
// this is from Arduino's wiring_analog.cpp

uint8_t analog_reference = DEFAULT;

void analogReference(uint8_t mode)
{
  // can't actually set the register here because the default setting
  // will connect AVCC and the AREF pin, which would cause a short if
  // there's something connected to AREF.
  analog_reference = mode;
}

int analogRead(uint8_t pin)
{
  uint8_t low, high;

#if defined(analogPinToChannel)
#if defined(__AVR_ATmega32U4__)
  if (pin >= 18) pin -= 18; // allow for channel or pin numbers
#endif
  pin = analogPinToChannel(pin);
#elif defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  if (pin >= 54) pin -= 54; // allow for channel or pin numbers
#elif defined(__AVR_ATmega32U4__)
  if (pin >= 18) pin -= 18; // allow for channel or pin numbers
#elif defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega644__) || defined(__AVR_ATmega644A__) || defined(__AVR_ATmega644P__) || defined(__AVR_ATmega644PA__)
  if (pin >= 24) pin -= 24; // allow for channel or pin numbers
#else
  if (pin >= 14) pin -= 14; // allow for channel or pin numbers
#endif

#if defined(ADCSRB) && defined(MUX5)
  // the MUX5 bit of ADCSRB selects whether we're reading from channels
  // 0 to 7 (MUX5 low) or 8 to 15 (MUX5 high).
  ADCSRB = (ADCSRB & ~(1 << MUX5)) | (((pin >> 3) & 0x01) << MUX5);
#endif

  // set the analog reference (high two bits of ADMUX) and select the
  // channel (low 4 bits).  this also sets ADLAR (left-adjust result)
  // to 0 (the default).
#if defined(ADMUX)
  ADMUX = (analog_reference << 6) | (pin & 0x07);
#endif

  // without a delay, we seem to read from the wrong channel
  //delay(1);

#if defined(ADCSRA) && defined(ADCL)
  // start the conversion
  sbi(ADCSRA, ADSC);

  // ADSC is cleared when the conversion finishes
  while (bit_is_set(ADCSRA, ADSC));

  // we have to read ADCL first; doing so locks both ADCL
  // and ADCH until ADCH is read.  reading ADCL second would
  // cause the results of each conversion to be discarded,
  // as ADCL and ADCH would be locked when it completed.
  low  = ADCL;
  high = ADCH;
#else
  // we dont have an ADC, return 0
  low  = 0;
  high = 0;
#endif

  // combine the two bytes
  return (high << 8) | low;
}

// Right now, PWM output only works on the pins with
// hardware support.  These are defined in the appropriate
// pins_*.c file.  For the rest of the pins, we default
// to digital output.
void analogWrite(uint8_t pin, int val)
{
  // We need to make sure the PWM output is enabled for those pins
  // that support it, as we turn it off when digitally reading or
  // writing with them.  Also, make sure the pin is in output mode
  // for consistenty with Wiring, which doesn't require a pinMode
  // call for the analog output pins.
  pinMode(pin, OUTPUT);
  if (val == 0)
  {
    digitalWrite(pin, LOW);
  }
  else if (val == 255)
  {
    digitalWrite(pin, HIGH);
  }
  else
  {
    switch(digitalPinToTimer(pin))
    {
      // XXX fix needed for atmega8
      #if defined(TCCR0) && defined(COM00) && !defined(__AVR_ATmega8__)
      case TIMER0A:
        // connect pwm to pin on timer 0
        sbi(TCCR0, COM00);
        OCR0 = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR0A) && defined(COM0A1)
      case TIMER0A:
        // connect pwm to pin on timer 0, channel A
        sbi(TCCR0A, COM0A1);
        OCR0A = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR0A) && defined(COM0B1)
      case TIMER0B:
        // connect pwm to pin on timer 0, channel B
        sbi(TCCR0A, COM0B1);
        OCR0B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR1A) && defined(COM1A1)
      case TIMER1A:
        // connect pwm to pin on timer 1, channel A
        sbi(TCCR1A, COM1A1);
        OCR1A = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR1A) && defined(COM1B1)
      case TIMER1B:
        // connect pwm to pin on timer 1, channel B
        sbi(TCCR1A, COM1B1);
        OCR1B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR1A) && defined(COM1C1)
      case TIMER1C:
        // connect pwm to pin on timer 1, channel B
        sbi(TCCR1A, COM1C1);
        OCR1C = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR2) && defined(COM21)
      case TIMER2:
        // connect pwm to pin on timer 2
        sbi(TCCR2, COM21);
        OCR2 = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR2A) && defined(COM2A1)
      case TIMER2A:
        // connect pwm to pin on timer 2, channel A
        sbi(TCCR2A, COM2A1);
        OCR2A = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR2A) && defined(COM2B1)
      case TIMER2B:
        // connect pwm to pin on timer 2, channel B
        sbi(TCCR2A, COM2B1);
        OCR2B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR3A) && defined(COM3A1)
      case TIMER3A:
        // connect pwm to pin on timer 3, channel A
        sbi(TCCR3A, COM3A1);
        OCR3A = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR3A) && defined(COM3B1)
      case TIMER3B:
        // connect pwm to pin on timer 3, channel B
        sbi(TCCR3A, COM3B1);
        OCR3B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR3A) && defined(COM3C1)
      case TIMER3C:
        // connect pwm to pin on timer 3, channel C
        sbi(TCCR3A, COM3C1);
        OCR3C = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR4A)
      case TIMER4A:
        //connect pwm to pin on timer 4, channel A
        sbi(TCCR4A, COM4A1);
        #if defined(COM4A0)		// only used on 32U4
        cbi(TCCR4A, COM4A0);
        #endif
        OCR4A = val;	// set pwm duty
        break;
      #endif

      #if defined(TCCR4A) && defined(COM4B1)
      case TIMER4B:
        // connect pwm to pin on timer 4, channel B
        sbi(TCCR4A, COM4B1);
        OCR4B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR4A) && defined(COM4C1)
      case TIMER4C:
        // connect pwm to pin on timer 4, channel C
        sbi(TCCR4A, COM4C1);
        OCR4C = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR4C) && defined(COM4D1)
      case TIMER4D:
        // connect pwm to pin on timer 4, channel D
        sbi(TCCR4C, COM4D1);
        #if defined(COM4D0)		// only used on 32U4
        cbi(TCCR4C, COM4D0);
        #endif
        OCR4D = val;	// set pwm duty
        break;
      #endif


      #if defined(TCCR5A) && defined(COM5A1)
      case TIMER5A:
        // connect pwm to pin on timer 5, channel A
        sbi(TCCR5A, COM5A1);
        OCR5A = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR5A) && defined(COM5B1)
      case TIMER5B:
        // connect pwm to pin on timer 5, channel B
        sbi(TCCR5A, COM5B1);
        OCR5B = val; // set pwm duty
        break;
      #endif

      #if defined(TCCR5A) && defined(COM5C1)
      case TIMER5C:
        // connect pwm to pin on timer 5, channel C
        sbi(TCCR5A, COM5C1);
        OCR5C = val; // set pwm duty
        break;
      #endif

      case NOT_ON_TIMER:
      default:
        if (val < 128) {
          digitalWrite(pin, LOW);
        } else {
          digitalWrite(pin, HIGH);
        }
    }
  }
}

// ******************
// this is from Arduino's WInterrupts.c

static void nothing(void) {
}

static volatile voidFuncPtr intFunc[EXTERNAL_NUM_INTERRUPTS] = {
#if EXTERNAL_NUM_INTERRUPTS > 8
    #warning There are more than 8 external interrupts. Some callbacks may not be initialized.
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 7
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 6
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 5
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 4
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 3
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 2
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 1
    nothing,
#endif
#if EXTERNAL_NUM_INTERRUPTS > 0
    nothing,
#endif
};
// volatile static voidFuncPtr twiIntFunc;

void attachInterrupt(uint8_t interruptNum, void (*userFunc)(void), int mode) {
  if(interruptNum < EXTERNAL_NUM_INTERRUPTS) {
    intFunc[interruptNum] = userFunc;

    // Configure the interrupt mode (trigger on low input, any change, rising
    // edge, or falling edge).  The mode constants were chosen to correspond
    // to the configuration bits in the hardware register, so we simply shift
    // the mode into place.

    // Enable the interrupt.

    switch (interruptNum) {
#if defined(__AVR_ATmega32U4__)
  // I hate doing this, but the register assignment differs between the 1280/2560
  // and the 32U4.  Since avrlib defines registers PCMSK1 and PCMSK2 that aren't
  // even present on the 32U4 this is the only way to distinguish between them.
    case 0:
  EICRA = (EICRA & ~((1<<ISC00) | (1<<ISC01))) | (mode << ISC00);
  EIMSK |= (1<<INT0);
  break;
    case 1:
  EICRA = (EICRA & ~((1<<ISC10) | (1<<ISC11))) | (mode << ISC10);
  EIMSK |= (1<<INT1);
  break;
    case 2:
        EICRA = (EICRA & ~((1<<ISC20) | (1<<ISC21))) | (mode << ISC20);
        EIMSK |= (1<<INT2);
        break;
    case 3:
        EICRA = (EICRA & ~((1<<ISC30) | (1<<ISC31))) | (mode << ISC30);
        EIMSK |= (1<<INT3);
        break;
    case 4:
        EICRB = (EICRB & ~((1<<ISC60) | (1<<ISC61))) | (mode << ISC60);
        EIMSK |= (1<<INT6);
        break;
#elif defined(EICRA) && defined(EICRB) && defined(EIMSK)
    case 2:
      EICRA = (EICRA & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);
      EIMSK |= (1 << INT0);
      break;
    case 3:
      EICRA = (EICRA & ~((1 << ISC10) | (1 << ISC11))) | (mode << ISC10);
      EIMSK |= (1 << INT1);
      break;
    case 4:
      EICRA = (EICRA & ~((1 << ISC20) | (1 << ISC21))) | (mode << ISC20);
      EIMSK |= (1 << INT2);
      break;
    case 5:
      EICRA = (EICRA & ~((1 << ISC30) | (1 << ISC31))) | (mode << ISC30);
      EIMSK |= (1 << INT3);
      break;
    case 0:
      EICRB = (EICRB & ~((1 << ISC40) | (1 << ISC41))) | (mode << ISC40);
      EIMSK |= (1 << INT4);
      break;
    case 1:
      EICRB = (EICRB & ~((1 << ISC50) | (1 << ISC51))) | (mode << ISC50);
      EIMSK |= (1 << INT5);
      break;
    case 6:
      EICRB = (EICRB & ~((1 << ISC60) | (1 << ISC61))) | (mode << ISC60);
      EIMSK |= (1 << INT6);
      break;
    case 7:
      EICRB = (EICRB & ~((1 << ISC70) | (1 << ISC71))) | (mode << ISC70);
      EIMSK |= (1 << INT7);
      break;
#else
    case 0:
    #if defined(EICRA) && defined(ISC00) && defined(EIMSK)
      EICRA = (EICRA & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);
      EIMSK |= (1 << INT0);
    #elif defined(MCUCR) && defined(ISC00) && defined(GICR)
      MCUCR = (MCUCR & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);
      GICR |= (1 << INT0);
    #elif defined(MCUCR) && defined(ISC00) && defined(GIMSK)
      MCUCR = (MCUCR & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);
      GIMSK |= (1 << INT0);
    #else
      #error attachInterrupt not finished for this CPU (case 0)
    #endif
      break;

    case 1:
    #if defined(EICRA) && defined(ISC10) && defined(ISC11) && defined(EIMSK)
      EICRA = (EICRA & ~((1 << ISC10) | (1 << ISC11))) | (mode << ISC10);
      EIMSK |= (1 << INT1);
    #elif defined(MCUCR) && defined(ISC10) && defined(ISC11) && defined(GICR)
      MCUCR = (MCUCR & ~((1 << ISC10) | (1 << ISC11))) | (mode << ISC10);
      GICR |= (1 << INT1);
    #elif defined(MCUCR) && defined(ISC10) && defined(GIMSK) && defined(GIMSK)
      MCUCR = (MCUCR & ~((1 << ISC10) | (1 << ISC11))) | (mode << ISC10);
      GIMSK |= (1 << INT1);
    #else
      #warning attachInterrupt may need some more work for this cpu (case 1)
    #endif
      break;

    case 2:
    #if defined(EICRA) && defined(ISC20) && defined(ISC21) && defined(EIMSK)
      EICRA = (EICRA & ~((1 << ISC20) | (1 << ISC21))) | (mode << ISC20);
      EIMSK |= (1 << INT2);
    #elif defined(MCUCR) && defined(ISC20) && defined(ISC21) && defined(GICR)
      MCUCR = (MCUCR & ~((1 << ISC20) | (1 << ISC21))) | (mode << ISC20);
      GICR |= (1 << INT2);
    #elif defined(MCUCR) && defined(ISC20) && defined(GIMSK) && defined(GIMSK)
      MCUCR = (MCUCR & ~((1 << ISC20) | (1 << ISC21))) | (mode << ISC20);
      GIMSK |= (1 << INT2);
    #endif
      break;
#endif
    }
  }
}

void detachInterrupt(uint8_t interruptNum) {
  if(interruptNum < EXTERNAL_NUM_INTERRUPTS) {
    // Disable the interrupt.  (We can't assume that interruptNum is equal
    // to the number of the EIMSK bit to clear, as this isn't true on the
    // ATmega8.  There, INT0 is 6 and INT1 is 7.)
    switch (interruptNum) {
#if defined(__AVR_ATmega32U4__)
    case 0:
        EIMSK &= ~(1<<INT0);
        break;
    case 1:
        EIMSK &= ~(1<<INT1);
        break;
    case 2:
        EIMSK &= ~(1<<INT2);
        break;
    case 3:
        EIMSK &= ~(1<<INT3);
        break;
    case 4:
        EIMSK &= ~(1<<INT6);
        break;
#elif defined(EICRA) && defined(EICRB) && defined(EIMSK)
    case 2:
      EIMSK &= ~(1 << INT0);
      break;
    case 3:
      EIMSK &= ~(1 << INT1);
      break;
    case 4:
      EIMSK &= ~(1 << INT2);
      break;
    case 5:
      EIMSK &= ~(1 << INT3);
      break;
    case 0:
      EIMSK &= ~(1 << INT4);
      break;
    case 1:
      EIMSK &= ~(1 << INT5);
      break;
    case 6:
      EIMSK &= ~(1 << INT6);
      break;
    case 7:
      EIMSK &= ~(1 << INT7);
      break;
#else
    case 0:
    #if defined(EIMSK) && defined(INT0)
      EIMSK &= ~(1 << INT0);
    #elif defined(GICR) && defined(ISC00)
      GICR &= ~(1 << INT0); // atmega32
    #elif defined(GIMSK) && defined(INT0)
      GIMSK &= ~(1 << INT0);
    #else
      #error detachInterrupt not finished for this cpu
    #endif
      break;

    case 1:
    #if defined(EIMSK) && defined(INT1)
      EIMSK &= ~(1 << INT1);
    #elif defined(GICR) && defined(INT1)
      GICR &= ~(1 << INT1); // atmega32
    #elif defined(GIMSK) && defined(INT1)
      GIMSK &= ~(1 << INT1);
    #else
      #warning detachInterrupt may need some more work for this cpu (case 1)
    #endif
      break;

    case 2:
    #if defined(EIMSK) && defined(INT2)
      EIMSK &= ~(1 << INT2);
    #elif defined(GICR) && defined(INT2)
      GICR &= ~(1 << INT2); // atmega32
    #elif defined(GIMSK) && defined(INT2)
      GIMSK &= ~(1 << INT2);
    #elif defined(INT2)
      #warning detachInterrupt may need some more work for this cpu (case 2)
    #endif
      break;
#endif
    }

    intFunc[interruptNum] = nothing;
  }
}

#define IMPLEMENT_ISR(vect, interrupt) \
  ISR(vect) { \
    intFunc[interrupt](); \
  }

#if defined(__AVR_ATmega32U4__)

IMPLEMENT_ISR(INT0_vect, EXTERNAL_INT_0)
IMPLEMENT_ISR(INT1_vect, EXTERNAL_INT_1)
IMPLEMENT_ISR(INT2_vect, EXTERNAL_INT_2)
IMPLEMENT_ISR(INT3_vect, EXTERNAL_INT_3)
IMPLEMENT_ISR(INT6_vect, EXTERNAL_INT_4)

#elif defined(EICRA) && defined(EICRB)

IMPLEMENT_ISR(INT0_vect, EXTERNAL_INT_2)
IMPLEMENT_ISR(INT1_vect, EXTERNAL_INT_3)
IMPLEMENT_ISR(INT2_vect, EXTERNAL_INT_4)
IMPLEMENT_ISR(INT3_vect, EXTERNAL_INT_5)
IMPLEMENT_ISR(INT4_vect, EXTERNAL_INT_0)
IMPLEMENT_ISR(INT5_vect, EXTERNAL_INT_1)
IMPLEMENT_ISR(INT6_vect, EXTERNAL_INT_6)
IMPLEMENT_ISR(INT7_vect, EXTERNAL_INT_7)

#else

IMPLEMENT_ISR(INT0_vect, EXTERNAL_INT_0)
IMPLEMENT_ISR(INT1_vect, EXTERNAL_INT_1)

#if defined(EICRA) && defined(ISC20)
IMPLEMENT_ISR(INT2_vect, EXTERNAL_INT_2)
#endif

#endif


// ******************
// this is from Arduino's WMath.cpp

void randomSeed(unsigned long seed)
{
  if (seed != 0) {
    srandom(seed);
  }
}

long random(long howbig)
{
  if (howbig == 0) {
    return 0;
  }
  return random() % howbig;
}

long random(long howsmall, long howbig)
{
  if (howsmall >= howbig) {
    return howsmall;
  }
  long diff = howbig - howsmall;
  return random(diff) + howsmall;
}

long map(long x, long in_min, long in_max, long out_min, long out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

unsigned int makeWord(unsigned int w) { return w; }
unsigned int makeWord(unsigned char h, unsigned char l) { return (h << 8) | l; }