/*
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
*/
#define ARDUBOY_CORE_WIRING_C
#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;
volatile unsigned char button_ticks_hold = 0;
volatile unsigned char button_ticks_now = 0;
volatile unsigned char button_ticks_last = 0;
volatile unsigned char bootloader_timer = 0;
#if defined(TIM0_OVF_vect)
ISR(TIM0_OVF_vect)
#else
ISR(TIMER0_OVF_vect, ISR_NAKED)
#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++;
*/
// save registers and SREG
asm volatile(
" push r16 \n\t"
" in r16, __SREG__ \n\t"
" push r16 \n\t" //use as more functional temp reg
" push r1 \n\t"
" clr r1 \n\t" //zero reg
" push r24 \n\t"
" push r25 \n\t"
" push r30 \n\t"
" push r31 \n\t"
);
asm volatile(
" lds r24, %[fract] \n\t" // f= timer0_fract;
" ldi r25, %[millis_inc] \n\t" // millis_inc = MILLIS_INC;
" subi r24, %[fract_inc] \n\t" // f += FRACT_INC;
" cpi r24, %[fract_max] \n\t" // if (f >= FRACT_MAX) {
" brcs 1f \n\t"
" subi r24, %[fract_max] \n\t" // f -= FRACT_MAX;
" inc r25 \n\t" // millis_inc++ }
"1: \n\t"
" sts %[fract], r24 \n\t" // timer0_fract = f;
" ld r24, z \n\t" //timer0_millis += millis_inc
" add r24, r25 \n\t"
" st z, r24 \n\t"
" ldd r25, z+1 \n\t"
" adc r25, r1 \n\t"
" std z+1, r25 \n\t" // r25 = (millis >>8)
" ldd r16, z+2 \n\t"
" adc r16, r1 \n\t"
" std z+2, r16 \n\t" // r16 = (millis >>16)
" ldd r24, z+3 \n\t"
" adc r24, r1 \n\t"
" std z+3, r24 \n\t"
" eor r16, r25 \n\t" //button_ticks_now = (millis >> 12)
" andi r16, 0x0F \n\t"
" eor r16, r25 \n\t"
" swap r16 \n\t"
" sts %[buttons_now], r16 \n\t"
:
: [millis] "z" (&timer0_millis),
[fract] "" (&timer0_fract),
[buttons_now] "" (&button_ticks_now),
[millis_inc] "M" (MILLIS_INC),
[fract_inc] "M" (256 - FRACT_INC), // negated for subi instruction
[fract_max] "M" (FRACT_MAX)
:
);
//Arduboy bootloader and reset button feature
asm volatile (
" rcall scan_buttons \n\t"
" cpse r24, r1 \n\t" //if (buttons) button_ticks_last = (uint8_t)(Millis >> 12)
" sts %[apd], r16 \n\t"
#ifdef AB_DEVKIT
" cpi r24, 0x50 \n\t" // test DevKit UP+DOWN for bootloader
#else
" cpi r24, 0x90 \n\t" // test arduboy UP+DOWN for bootloader
#endif
" brne 5f \n\t"
"2: lds r16, %[hold] \n\t"
" sub r25, r16 \n\t" // (uint8_t)(timer0_millis >> 8) - button_ticks_last
" cpi r25, 6 \n\t"
" brcs 6f \n\t" // if ((millis - hold) >= 6) {
"3: ldi r24, 0x77 \n\t"
" sts 0x800, r24 \n\t"
" sts 0x801, r24 \n\t"
" ldi r24, %[value1] \n\t"
" ldi r25, %[value2] \n\t"
" sts %[wdtcsr], r24 \n\t"
" sts %[wdtcsr], r25 \n\t"
" rjmp .-2 \n\t" // }
"5: \n\t"
" sts %[hold], r25 \n\t" //button_ticks_hold = (uint8_t)(Millis >> 8)
"6: \n\t"
" lds r24, %[btimer] \n\t" //if (bootloader_timer--) {
" subi r24, 1 \n\t"
" brcs 7f \n\t"
" sts %[btimer],r24 \n\t"
" breq 3b \n\t" // if (bootloader_timer == 0) runBootLoader;
"7: \n\t" //}
:
: [hold] "" (&button_ticks_hold),
[apd] "" (&button_ticks_last),
[btimer] "" (&bootloader_timer),
[value1] "M" ((uint8_t)(_BV(WDCE) | _BV(WDE))),
[value2] "M" ((uint8_t)(_BV(WDE))),
[wdtcsr] "M" (_SFR_MEM_ADDR(WDTCSR))
:
);
//timer0_overflow_count++;
asm volatile (
" ld r24, z \n\t"
" ldd r25, z+1 \n\t"
" adiw r24, 1 \n\t"
" st z, r24 \n\t"
" std z+1, r25 \n\t"
" ldd r24, z+2 \n\t"
" ldd r25, z+3 \n\t"
" adc r24, r1 \n\t"
" adc r25, r1 \n\t"
" std z+2, r24 \n\t"
" std z+3, r25 \n\t"
:
: "z" (&timer0_overflow_count)
);
//restore registers and retirn from interrupt
asm volatile (
" pop r31 \n\t"
" pop r30 \n\t"
" pop r25 \n\t"
" pop r24 \n\t"
" pop r1 \n\t"
" pop r16 \n\t"
" out __SREG__, r16 \n\t"
" pop r16 \n\t"
" reti \n\t"
".global scan_buttons \n\t"
"scan_buttons: \n\t"
#ifdef AB_DEVKIT
" in r24, %[pinb] \n\t" // down, left, up buttons
" com r24 \n\t"
" andi r24, 0x70 \n\t"
" sbis %[pinc], 6 \n\t" // right button
" ori r24, 0x04 \n\t"
" sbis %[pinf], 7 \n\t" // A button
" ori r24, 0x02 \n\t"
" sbis %[pinf], 6 \n\t" // B button
" ori r24, 0x01 \n\t"
#else
" in r24, %[pinf] \n\t" // directional buttons
" com r24 \n\t"
" andi r24, 0xF0 \n\t"
" sbis %[pine], 6 \n\t" // A button
" ori r24, 0x08 \n\t"
" sbis %[pinb], 4 \n\t" // B button
" ori r24, 0x04 \n\t"
#endif
" ret \n\t" // Z flag set from AND when no button is pressed
:
: [pinf] "I" (_SFR_IO_ADDR(PINF)),
[pine] "I" (_SFR_IO_ADDR(PINE)),
[pinc] "I" (_SFR_IO_ADDR(PINC)),
[pinb] "I" (_SFR_IO_ADDR(PINB))
);
}
unsigned char buttonsIdleTime()
{
return button_ticks_now - button_ticks_last;
}
unsigned char millisChar()
{
return *(unsigned char*)&timer0_millis;
}
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());
*/
//assembly optimalisation
register unsigned long m asm("r22");
asm volatile(
" in r18, %[sreg] \n" //oldSREG = SREG
" cli \n" //
" ld r23, x+ \n" // m = timer0_overflow_count << 8
" ld r24, x+ \n"
" ld r25, x \n"
" in r22, %[tcnt] \n" // (m << 8) | t
" out %[sreg], r18 \n" //SREG = oldSREG
" sbis %[tif], %[tov] \n" // if ((TIFR & _BV(TOV) &&
" rjmp 1f \n"
" cpi r22, 0xFF \n" // t < 0xFF)
" brcc 1f \n"
" \n"
" subi r23, 0xFF \n" // m++ (m+=256)
" sbci r24, 0xFF \n" //
" sbci r25, 0xFF \n" //
"1: \n"
" ldi r18,%[fm] \n" // *( 64 / clockCyclesPerMicrosecond()
"2: \n"
" add r22, r22 \n"
" adc r23, r23 \n"
" adc r24, r24 \n"
" adc r25, r25 \n"
" dec r18 \n"
" brne 2b \n"
: "=d" (m)
: [sreg] "I" (_SFR_IO_ADDR(SREG)),
#if defined(TCNT0)
[tcnt] "I" (_SFR_IO_ADDR(TCNT0)),
#elif defined(TCNT0L)
[tcnt] "I" (_SFR_IO_ADDR(TCNT0L)),
#else
#error TIMER 0 not defined
#endif
#ifdef TIFR0
[tif] "I" (_SFR_IO_ADDR(TIFR0)),
#else
[tif] "I" (_SFR_IO_ADDR(TIFR)),
#endif
[tov] "M" (TOV0),
#if (F_CPU == 8000000L)
[fm] "M" (4),
#elif (F_CPU ==16000000L)
[fm] "M" (2),
#else
#error this version of wiring.c only supports 8MHz and 16MHz CPU clock
#endif
"x" (&timer0_overflow_count)
: "r18"
);
}
void delay(unsigned long ms)
{
/*
uint32_t start = micros();
while (ms > 0) {
yield();
while ( ms > 0 && (micros() - start) >= 1000) {
ms--;
start += 1000;
}
}
*/
//assembly optimalisation
asm volatile(
" movw r20, %A0 \n" //ms
" movw r30, %C0 \n"
" call micros \n" //endMicros = micros()
"1: \n"
" subi r20, 1 \n" //while (ms > 0)
" sbc r21, r1 \n"
" sbc r30, r1 \n"
" sbc r31, r1 \n"
" brcs 2f \n"
" \n"
" subi r22, 0x18 \n" //endMicros += 1000
" sbci r23, 0xFC \n"
" sbci r24, 0xFF \n"
" sbci r25, 0xFF \n"
" rjmp 1b \n"
"2: \n"
" movw r20, r22 \n"
" movw r30, r24 \n"
"3: \n"
" call micros \n" //while (micros() < endMicros);
" cp r22, r20 \n"
" cpc r23, r21 \n"
" cpc r24, r30 \n"
" cpc r25, r31 \n"
" brcs 3b \n"
:
: "d" (ms),
"" (micros)
: "r20", "r21", "r30", "r31", /*from micros: */ "r18", "r26", "r27"
);
}
void delayShort(unsigned short ms)
{
asm volatile(
" call micros \n" //endMicros = micros()
"1: \n"
" sbiw r30, 1 \n" //while (ms > 0)
" brcs 2f \n"
" \n"
" subi r22, 0x18 \n" //endMicros += 1000
" sbci r23, 0xFC \n"
" sbci r24, 0xFF \n"
" sbci r25, 0xFF \n"
" rjmp 1b \n"
"2: \n"
" movw r20, r22 \n"
" movw r30, r24 \n"
"3: \n"
" call micros \n" //while (micros() < endMicros);
" cp r22, r20 \n"
" cpc r23, r21 \n"
" cpc r24, r30 \n"
" cpc r25, r31 \n"
" brcs 3b \n"
:
: "z" (ms),
"" (micros)
: "r20", "r21", "r22", "r23", /*from micros: */ "r18", "r26", "r27"
);
}
/* 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() //assembly optimized by 68 bytes
{
// 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);
asm volatile(
" ldi r24, %[value] \n\t"
" out %[tccr0a], r24 \n\t"
:
: [tccr0a] "I" (_SFR_IO_ADDR(TCCR0A)),
[value] "M" (_BV(WGM01) | _BV(WGM00))
: "r24"
);
#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);
asm volatile(
" ldi r24, %[value] \n\t"
" out %[tccr0b], r24 \n\t"
:
: [tccr0b] "I" (_SFR_IO_ADDR(TCCR0B)),
[value] "M" (_BV(CS01) | _BV(CS00))
: "r24"
);
#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)
TIMSK0 = _BV(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
asm volatile(
" ldi r30, %[tccr1b] \n\t"
" ldi r31, 0x00 \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [tccr1b] "M" (_SFR_MEM_ADDR(TCCR1B)),
#if F_CPU >= 8000000L
[value] "M" (_BV(CS11) | _BV(CS10))
#else
[value] "M" (_BV(CS11))
#endif
: "r24", "r30", "r31"
);
#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);
asm volatile(
" ldi r30, %[tccr1a] \n\t"
" ldi r24, %[wgm10] \n\t"
" st z, r24 \n\t"
:
: [tccr1a] "M" (_SFR_MEM_ADDR(TCCR1A)),
[wgm10] "M" (_BV(WGM10))
: "r24", "r30", "r31"
);
#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);
asm volatile(
" ldi r30, %[tccr3b] \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [tccr3b] "M" (_SFR_MEM_ADDR(TCCR3B)),
[value] "M" (_BV(CS31) | _BV(CS30))
: "r24", "r30", "r31"
);
//sbi(TCCR3A, WGM30); // put timer 3 in 8-bit phase correct pwm mode
asm volatile(
" ldi r30, %[tccr3a] \n\t"
" ldi r24, %[wgm30] \n\t"
" st z, r24 \n\t"
:
: [tccr3a] "M" (_SFR_MEM_ADDR(TCCR3A)),
[wgm30] "M" (_BV(WGM30))
: "r24", "r30", "r31"
);
#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);
asm volatile(
" ldi r30, %[tccr4b] \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [tccr4b] "M" (_SFR_MEM_ADDR(TCCR4B)),
[value] "M" (_BV(CS42) | _BV(CS41) | _BV(CS40))
: "r24", "r30", "r31"
);
//sbi(TCCR4D, WGM40); // put timer 4 in phase- and frequency-correct PWM mode
asm volatile(
" ldi r30, %[tccr4d] \n\t"
" ldi r24, %[wgm40] \n\t"
" st z, r24 \n\t"
:
: [tccr4d] "M" (_SFR_MEM_ADDR(TCCR4D)),
[wgm40] "M" (_BV(WGM40))
: "r24", "r30", "r31"
);
//sbi(TCCR4A, PWM4A); // enable PWM mode for comparator OCR4A
asm volatile(
" ldi r30, %[tccr4a] \n\t"
" ldi r24, %[pwm4a] \n\t"
" st z, r24 \n\t"
:
: [tccr4a] "M" (_SFR_MEM_ADDR(TCCR4A)),
[pwm4a] "M" (_BV(PWM4A))
: "r24", "r30", "r31"
);
//sbi(TCCR4C, PWM4D); // enable PWM mode for comparator OCR4D
asm volatile(
" ldi r30, %[tccr4c] \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [tccr4c] "M" (_SFR_MEM_ADDR(TCCR4C)),
[value] "M" (_BV(PWM4D))
: "r24", "r30", "r31"
);
#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);
asm volatile(
" ldi r30, %[adcsra] \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [adcsra] "M" (_SFR_MEM_ADDR(ADCSRA)),
[value] "M" (_BV(ADPS2) |_BV(ADPS1) | _BV(ADPS0))
: "r24"
);
#elif F_CPU >= 8000000 // 8 MHz / 64 = 125 KHz
//sbi(ADCSRA, ADPS2);
//sbi(ADCSRA, ADPS1);
//cbi(ADCSRA, ADPS0);
asm volatile(
" ldi r30, %[adcsra] \n\t"
" ldi r24, %[value] \n\t"
" st z, r24 \n\t"
:
: [adcsra] "M" (_SFR_MEM_ADDR(ADCSRA)),
[value] "M" (_BV(ADPS2) | _BV(ADPS1))
: "r24", "r30", "r31"
);
#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);
asm volatile(
" ori r24, %[aden] \n\t"
" st z, r24 \n\t"
:
: [aden] "M" (_BV(ADEN))
: "r24", "r30", "r31"
);
#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
}