Делаем металлоискатель на ATtiny24A

#include <avr/io.h>
#include <avr/interrupt.h>
#include "mySerial.cpp"

MySerial ms(&PORTB, &PINB, &DDRB, 0, &PORTB, &PINB, &DDRB, 1);

volatile uint16_t maxAdc = 0; // максимальное показание АЦП (в резонансе на максимальной добротности)
volatile uint8_t dispMode = 0; // 0 - поиск резонанса, 1 - рабочий режим
volatile uint8_t flags0 = 0; // [0] - need setRes
volatile uint16_t adcSource = 0;
//volatile bool needADC = false;
#define ADC_SOURCE_ARRAY_SIZE_POWER 5
#define ADC_SOURCE_ARRAY_SIZE (1 << ADC_SOURCE_ARRAY_SIZE_POWER)
uint16_t adcSourceArray[ADC_SOURCE_ARRAY_SIZE];
uint8_t adcSourceArrayLastWrited = 0;
void showVal(void);

ISR(ADC_vect){
	//adcSourceArrayLastWrited++;
	if(++adcSourceArrayLastWrited >= ADC_SOURCE_ARRAY_SIZE)
		adcSourceArrayLastWrited = 0;
	adcSourceArray[adcSourceArrayLastWrited] = ADCL | (ADCH << 8);
	uint16_t adcSourceTmp = 0;
	for(uint8_t i = 0; i < ADC_SOURCE_ARRAY_SIZE; i++)
		adcSourceTmp += adcSourceArray[adcSourceArrayLastWrited];
	adcSource = (adcSourceTmp >> ADC_SOURCE_ARRAY_SIZE_POWER);
	//adcSource = ADCL | (ADCH << 8);
	//needADC = false;
}

volatile uint8_t pinaChanged = 0;
volatile uint8_t tim0_ovf_counter = 0;
//uint32_t ticks = 0;
volatile uint16_t ticks10ms = 0;
//volatile uint16_t ticks = 0;
ISR(TIM0_OVF_vect)
{		
	//ticks++;
	//if(255 == tim0_ovf_counter++){ // ticks every 65.5 ms
	if(39 == (tim0_ovf_counter++)){ // ticks every 10 ms
		tim0_ovf_counter = 0;
		ticks10ms++;
		if(pinaChanged > 0)
			pinaChanged--;
	}
}

uint16_t dist16(uint16_t lo, uint16_t hi){
	return (lo <= hi) ? (hi - lo) : (0xFFFF - lo + hi);
}
/*void delayTicks(uint16_t val){
	uint16_t tim0_ovf_counter0 = tim0_ovf_counter;
	while(dist16(tim0_ovf_counter0, tim0_ovf_counter) < val)
		showVal();
}*/
void delay10ms(uint16_t val){
	uint16_t ticks10ms0 = ticks10ms;
	while(dist16(ticks10ms0, ticks10ms) < val)
		showVal();
}

void showVal(void){
	ms.sendByte(adcSource >> 2);
	switch(dispMode){
		case 0:
			OCR0A = adcSource >> 2;
		break;
		case 1:
			uint16_t maxAdcPlus = maxAdc + 2;
			uint16_t dispVal = (maxAdcPlus > adcSource) ? ((maxAdcPlus - adcSource)) : 0;
			dispVal <<= 4;
			if(dispVal > 255)
				dispVal = 255;
			OCR0A = dispVal;
		break;
	}
}

void setRes(void)
{
	dispMode = 0;
	uint16_t maxOCR = 0;
	maxAdc = 0;
	for(uint16_t curOCR = 35; curOCR < 50; curOCR++){
		OCR1A = curOCR;
		OCR1B = (curOCR >> 1);
		//uint32_t ticks0 = ticks;
		//uint16_t ticks0 = ticks;		
		//while(dist16(ticks0, ticks) < 20)
		//	showVal();
		delay10ms(30);
		if(adcSource > maxAdc){
			maxAdc = adcSource;
			maxOCR = curOCR;
		}
	}
	OCR1A = maxOCR;
	OCR1B = (maxOCR >> 1);
	dispMode = 1;
}

ISR(PCINT0_vect)
{	
	if(pinaChanged > 0)
		return;
	pinaChanged = 5;
	if(0 == (PINA & (1 << 7)))
		flags0 |= 1;
}


int main(void)
{
	// init PWM:
	DDRB |= 4;  // OC0A as output
	//TIMSK0 |= 7; // разрешаем TIM0_OVF_vect, TIM0_COMPA_vect, TIM0_COMPB_vect
	TIMSK0 |= 1; // разрешаем TIM0_OVF_vect
	TCCR0B |= 1; // no prescaling. OVF каждые 256 мкс (3.91 кГц)
	//TCCR0B |= 2; // clk/8
	//TCCR0B |= 3; // clk/64
	//TCCR0B |= 5; // clk/1024. OVF каждые 262 мс (3.815 Гц)
	TCCR0A |= (3 | (1 << 7)); //WGM0[2:0] = 3 - fawt PWM mode. bit7 - дёргать ногой
	//OCR0A = 150;
	//OCR0B = 100;
	// :init PWM
	
	// init ADC:
	//ADMUX |= (1 << 7); // internal 1.1V reference. Comment this to use VCC as reference
	//ADMUX |= (1 << 3) | 1; // MUX[5:0] = 001001. Res = ADC0 - ADC1. Gain = 20
	ADMUX |= (1 << 3); // MUX[5:0] = 001000. Res = ADC0 - ADC1. Gain = 1
	ADCSRA |= ((1 << 7) // enable ADC
		| (1 << 5) // ADC Auto Trigger Enable. Постоянно работает
		| (1 << 6) // запускаем 1е преобразование
		| (1 << 3)   // ADC interrupt enable
		| (1 << 2)); // prescaller = 16 (надо 50-200 kHz)
	// :init ADC
	
	// init 16-bit timer: // pin7 = MOSI = PA6 = OC1A
	//DDRA |= (1 << 6); // OC1A as output
	DDRA |= (1 << 5); // OC1B as output
	//TCCR1A |= (1 << 6); // Toggle OC1A/OC1B on Compare Match
	TCCR1A |= (1 << 5) // Clear OC1B on Compare Match, set OC1B at BOTTOM (non-inverting mode)
		| (3); // set WGM10 and WGM11 // WGM1[3:0] = 1111 - Fast PWM, TOP = OCR1A.	
//	TCCR1A |= (1 << 6) | (1 << 7) // Set OC1A on Compare Match (Set output to high level).
//			| (1 << 5); // Clear OC1B on Compare Match	(Set output to low level)
	TCCR1B |= 1 // no prescalling
			| (1 << 3) | (1 << 4); // set WGM12 and WGM13
	//TIMSK1 |= (1 << 2) | (1 << 1) | 1; // enable all interrupts
	OCR1B = 21;
	OCR1A = 42;
	//for(;;){;};
	// :init 16-bit timer
	
	// init button:
	PORTA |= (1 << 7); // включаем подтягивающий резистор на 6-й ноге. PA7 = PCINT7
	GIMSK |= (1 << 4); // Pin Change Interrupt Enable 0
	PCMSK0 |= (1 << 7); // включаем прерывание PCINT7
	// :init button
	
	sei();
	flags0 = 1; // это экономит 22 байта по сравнению с присвоением при объявлении!
	while(1){
		showVal();
		//ms.sendByte(0x99);
		if(0 != (1 & flags0)){
			setRes();
			flags0 &= ~1;
		}
	}
}

#include <avr/io.h>
#include <avr/interrupt.h>

class MySerial{
	public:
	volatile uint8_t *dataPort;
	volatile uint8_t *dataPin;
	volatile uint8_t *dataDDR;
	volatile uint8_t *clockPort;
	volatile uint8_t *clockPin;
	volatile uint8_t *clockDDR;
	uint8_t dataPinMask, clockPinMask;
	uint8_t rBit,
		lastState, // (dataPin << 1) | clockPin
		inData;
	// MySerial ms(&PORTD, &PIND, &DDRD, 2, &PORTD, &PIND, &DDRD, 3);
	MySerial(
		volatile uint8_t *_dataPort,
		volatile uint8_t *_dataPin,
		volatile uint8_t *_dataDDR,
		uint8_t _dataPinN,
		volatile uint8_t *_clockPort,
		volatile uint8_t *_clockPin,
		volatile uint8_t *_clockDDR,
		uint8_t _clockPinN
	){
		rBit = 255;
		lastState = 3;
		inData = 0;
		dataPort = _dataPort;
		dataPin = _dataPin;
		dataDDR = _dataDDR;
		dataPinMask = (1 << _dataPinN);
		clockPort = _clockPort;
		clockPin = _clockPin;
		clockDDR = _clockDDR;
		clockPinMask = (1 << _clockPinN);
	}
	void dataZero() {
		*dataPort &= ~dataPinMask; //digitalWrite(pinData, 0);
		*dataDDR |= dataPinMask;   //pinMode(pinData, OUTPUT);
	}
	void dataRelease() {
		*dataDDR &= ~dataPinMask; //pinMode(pinData, INPUT);
		*dataPort |= dataPinMask; //digitalWrite(pinData, 1);
	}
	void clockZero() {
		*clockPort &= ~clockPinMask; //digitalWrite(pinClock, 0);
		*clockDDR |= clockPinMask;  //pinMode(pinClock, OUTPUT);
	}
	void clockRelease() {
		*clockDDR &= ~clockPinMask; //pinMode(pinClock, INPUT);
		*clockPort |= clockPinMask; //digitalWrite(pinClock, 1);
	}
	void pause() {
		//delay(v * 1);
		//unsigned long time = micros();
		//while(v-- > 0)
		for(uint16_t i = 0; i < 250; i++)
			__asm__ __volatile__(
				"nop"
			);
		//time = micros() - time;
		//LOG("Paused "); LOG(time); LOGLN("us");
	}
	void sendByte(uint8_t data){
		//LOG("Sending byte: "); LOGLN(data);
		// отрицательный фронт data при clock = 1:
		dataRelease();
		clockRelease();
		pause();
		dataZero();
		pause();
		
		//LOGLN("Going to loop...");
		for(uint8_t i = 0; i < 8; i++){
			clockZero();
			pause();
			if( 0 == (data & (1 << 7)) )
				dataZero();
			else
				dataRelease();
			//LOG("Sending bit "); LOGLN((data & (1 << 7)));
			pause();
			clockRelease();
			pause();

			data = data << 1;
		}
		
		// положительный фронт data при clock = 1:
		dataZero();
		pause();
		dataRelease();
		pause();
	}	
	void tick(){
		//uint8_t curState = (digitalRead(pinData) << 1) | digitalRead(pinClock);
		dataRelease();
		clockRelease();
		uint8_t curState = 0;
		if(0 != (*dataPin & dataPinMask))
			curState |= 2;
		if(0 != (*clockPin & clockPinMask))
			curState |= 1;

		//LOGLN(curState);
		if((3 == lastState) && (1 == curState)) // началась передача
		rBit = 7;
		if(255 != rBit)
		if( (0 == (lastState & 1)) && (1 == (curState & 1)) ) { // пришёл положительный фронт clock
			//LOG("Getted bit "); LOGLN((curState >> 1));
			if( 0 == (curState >> 1) )
				inData &= ~(1 << rBit);
			else
				inData |= (1 << rBit);
			rBit--;
		}
		
		if( (1 == lastState) && (3 == curState) ){ // закончилась передача
			//LOG("Recieved byte: "); LOGLN(inData);
			rBit = 255;
			//delay(5000);
		}
		lastState = curState;
	}
};