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Diffstat (limited to 'cores/arduino/wiring.c')
| -rw-r--r-- | cores/arduino/wiring.c | 392 |
1 files changed, 0 insertions, 392 deletions
diff --git a/cores/arduino/wiring.c b/cores/arduino/wiring.c deleted file mode 100644 index 8caf455..0000000 --- a/cores/arduino/wiring.c +++ /dev/null @@ -1,392 +0,0 @@ -/* - 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 -*/ - -#include "wiring_private.h" - -// 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; -volatile unsigned long timer0_millis = 0; -static unsigned char timer0_fract = 0; - -#if defined(TIM0_OVF_vect) -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 = timer0_millis; - unsigned char f = timer0_fract; - - m += MILLIS_INC; - f += FRACT_INC; - if (f >= FRACT_MAX) { - f -= FRACT_MAX; - m += 1; - } - - timer0_fract = f; - timer0_millis = m; - timer0_overflow_count++; -} - -unsigned long millis() -{ - unsigned long m; - uint8_t oldSREG = SREG; - - // disable interrupts while we read timer0_millis or we might get an - // inconsistent value (e.g. in the middle of a write to timer0_millis) - cli(); - m = timer0_millis; - 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 adventurous 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 preceding commands. - // we just burned 22 (24) cycles above, remove 5, (5*4=20) - // us is at least 6 so we can subtract 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 preceding commands. - // we just burned 26 (28) cycles above, remove 7, (7*4=28) - // us is at least 10 so we can subtract 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 preceding commands. - // we just burned 19 (21) cycles above, remove 5, (5*4=20) - // us is at least 8 so we can subtract 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 preceding commands. - // we just burned 20 (22) cycles above, remove 5, (5*4=20) - // us is at least 6 so we can subtract 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 preceding commands. - // we just burned 17 (19) cycles above, remove 4, (4*4=16) - // us is at least 6 so we can subtract 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 subtract 22) - - // compensate for the time taken by the preceding 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() -{ - // this needs to be called before setup() or some functions won't - // work there - sei(); - - // 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 - - // timers 1 and 2 are used for phase-correct hardware pwm - // this is better for motors as it ensures an even waveform - // note, however, that fast pwm mode can achieve a frequency of up - // 8 MHz (with a 16 MHz clock) at 50% duty cycle - -#if defined(TCCR1B) && defined(CS11) && defined(CS10) - TCCR1B = 0; - - // set timer 1 prescale factor to 64 - sbi(TCCR1B, CS11); -#if F_CPU >= 8000000L - sbi(TCCR1B, CS10); -#endif -#elif defined(TCCR1) && defined(CS11) && defined(CS10) - sbi(TCCR1, CS11); -#if F_CPU >= 8000000L - sbi(TCCR1, CS10); -#endif -#endif - // put timer 1 in 8-bit phase correct pwm mode -#if defined(TCCR1A) && defined(WGM10) - sbi(TCCR1A, WGM10); -#endif - - // set timer 2 prescale factor to 64 -#if defined(TCCR2) && defined(CS22) - sbi(TCCR2, CS22); -#elif defined(TCCR2B) && defined(CS22) - sbi(TCCR2B, CS22); -//#else - // Timer 2 not finished (may not be present on this CPU) -#endif - - // configure timer 2 for phase correct pwm (8-bit) -#if defined(TCCR2) && defined(WGM20) - sbi(TCCR2, WGM20); -#elif defined(TCCR2A) && defined(WGM20) - sbi(TCCR2A, WGM20); -//#else - // Timer 2 not finished (may not be present on this CPU) -#endif - -#if defined(TCCR3B) && defined(CS31) && defined(WGM30) - sbi(TCCR3B, CS31); // set timer 3 prescale factor to 64 - sbi(TCCR3B, CS30); - sbi(TCCR3A, WGM30); // put timer 3 in 8-bit phase correct pwm mode -#endif - -#if defined(TCCR4A) && defined(TCCR4B) && defined(TCCR4D) /* beginning of timer4 block for 32U4 and similar */ - sbi(TCCR4B, CS42); // set timer4 prescale factor to 64 - sbi(TCCR4B, CS41); - sbi(TCCR4B, CS40); - sbi(TCCR4D, WGM40); // put timer 4 in phase- and frequency-correct PWM mode - sbi(TCCR4A, PWM4A); // enable PWM mode for comparator OCR4A - sbi(TCCR4C, PWM4D); // enable PWM mode for comparator OCR4D -#else /* beginning of timer4 block for ATMEGA1280 and ATMEGA2560 */ -#if defined(TCCR4B) && defined(CS41) && defined(WGM40) - sbi(TCCR4B, CS41); // set timer 4 prescale factor to 64 - sbi(TCCR4B, CS40); - sbi(TCCR4A, WGM40); // put timer 4 in 8-bit phase correct pwm mode -#endif -#endif /* end timer4 block for ATMEGA1280/2560 and similar */ - -#if defined(TCCR5B) && defined(CS51) && defined(WGM50) - sbi(TCCR5B, CS51); // set timer 5 prescale factor to 64 - sbi(TCCR5B, CS50); - sbi(TCCR5A, WGM50); // put timer 5 in 8-bit phase correct pwm mode -#endif - -#if defined(ADCSRA) - // set a2d prescaler so we are inside the desired 50-200 KHz range. - #if F_CPU >= 16000000 // 16 MHz / 128 = 125 KHz - sbi(ADCSRA, ADPS2); - sbi(ADCSRA, ADPS1); - sbi(ADCSRA, ADPS0); - #elif F_CPU >= 8000000 // 8 MHz / 64 = 125 KHz - sbi(ADCSRA, ADPS2); - sbi(ADCSRA, ADPS1); - cbi(ADCSRA, ADPS0); - #elif F_CPU >= 4000000 // 4 MHz / 32 = 125 KHz - sbi(ADCSRA, ADPS2); - cbi(ADCSRA, ADPS1); - sbi(ADCSRA, ADPS0); - #elif F_CPU >= 2000000 // 2 MHz / 16 = 125 KHz - sbi(ADCSRA, ADPS2); - cbi(ADCSRA, ADPS1); - cbi(ADCSRA, ADPS0); - #elif F_CPU >= 1000000 // 1 MHz / 8 = 125 KHz - cbi(ADCSRA, ADPS2); - sbi(ADCSRA, ADPS1); - sbi(ADCSRA, ADPS0); - #else // 128 kHz / 2 = 64 KHz -> This is the closest you can get, the prescaler is 2 - cbi(ADCSRA, ADPS2); - cbi(ADCSRA, ADPS1); - sbi(ADCSRA, ADPS0); - #endif - // enable a2d conversions - sbi(ADCSRA, ADEN); -#endif - - // the bootloader connects pins 0 and 1 to the USART; disconnect them - // here so they can be used as normal digital i/o; they will be - // reconnected in Serial.begin() -#if defined(UCSRB) - UCSRB = 0; -#elif defined(UCSR0B) - UCSR0B = 0; -#endif -} |