Arduino/ATMega328 Snippets

datatype-sizes.cpp

Serial.println("SCHAR_MIN = " + String(SCHAR_MIN, DEC) + ", " + String(SCHAR_MIN, HEX));                //  minimum value for a signed char
Serial.println("SCHAR_MAX = " + String(SCHAR_MAX, DEC) + ", " + String(SCHAR_MAX, HEX));                //  maximum value for a signed char
Serial.println("UCHAR_MAX = " + String(UCHAR_MAX, DEC) + ", " + String(UCHAR_MAX, HEX));                //  maximum value for an unsigned char
Serial.println("CHAR_MIN = " + String(CHAR_MIN, DEC) + ", " + String(CHAR_MIN, HEX));                   //  minimum value for a char
Serial.println("CHAR_MAX = " + String(CHAR_MAX, DEC) + ", " + String(CHAR_MAX, HEX));                   //  maximum value for a char
Serial.println("SHRT_MIN = " + String(SHRT_MIN, DEC) + ", " + String(SHRT_MIN, HEX));                   //  minimum value for a short
Serial.println("SHRT_MAX = " + String(SHRT_MAX, DEC) + ", " + String(SHRT_MAX, HEX));                   //  maximum value for a short
Serial.println("USHRT_MAX = " + String(USHRT_MAX, DEC) + ", " + String(USHRT_MAX, HEX));                //  maximum value for an unsigned short
Serial.println("INT_MIN = " + String(INT_MIN, DEC) + ", " + String(INT_MIN, HEX));                      //  minimum value for an int
Serial.println("INT_MAX = " + String(INT_MAX, DEC) + ", " + String(INT_MAX, HEX));                      //  maximum value for an int
Serial.println("UINT_MAX = " + String(UINT_MAX, DEC) + ", " + String(UINT_MAX, HEX));                   //  maximum value for an unsigned int
Serial.println("LONG_MIN = " + String(LONG_MIN, DEC) + ", " + String(LONG_MIN, HEX));                   //  minimum value for a long
Serial.println("LONG_MAX = " + String(LONG_MAX, DEC) + ", " + String(LONG_MAX, HEX));                   //  maximum value for a long
Serial.println("ULONG_MAX = " + String(ULONG_MAX, DEC) + ", " + String(ULONG_MAX, HEX));                //  maximum value for an unsigned long
Serial.println("LLONG_MIN = " + String(LLONG_MIN, DEC) + ", " + String(LLONG_MIN, HEX));                //  minimum value for a long long
Serial.println("LLONG_MAX = " + String(LLONG_MAX, DEC) + ", " + String(LLONG_MAX, HEX));                //  maximum value for a long long
Serial.println("ULLONG_MAX = " + String(ULLONG_MAX, DEC) + ", " + String(ULLONG_MAX, HEX));             //  maximum value for an unsigned long long
Serial.println("PTRDIFF_MIN = " + String(PTRDIFF_MIN, DEC) + ", " + String(PTRDIFF_MIN, HEX));          //  minimum value of ptrdiff_t
Serial.println("PTRDIFF_MAX = " + String(PTRDIFF_MAX, DEC) + ", " + String(PTRDIFF_MAX, HEX));          //  maximum value of ptrdiff_t
Serial.println("SIZE_MAX = " + String(SIZE_MAX, DEC) + ", " + String(SIZE_MAX, HEX));                   //  maximum value of size_t
Serial.println("SIG_ATOMIC_MIN = " + String(SIG_ATOMIC_MIN, DEC) + ", " + String(SIG_ATOMIC_MIN, HEX)); //  minimum value of sig_atomic_t
Serial.println("SIG_ATOMIC_MAX = " + String(SIG_ATOMIC_MAX, DEC) + ", " + String(SIG_ATOMIC_MAX, HEX)); //  maximum value of sig_atomic_t
Serial.println("WINT_MIN = " + String(WINT_MIN, DEC) + ", " + String(WINT_MIN, HEX));                   //  minimum value of wint_t
Serial.println("WINT_MAX = " + String(WINT_MAX, DEC) + ", " + String(WINT_MAX, HEX));                   //  maximum value of wint_t
Serial.println("WCHAR_MIN = " + String(WCHAR_MIN, DEC) + ", " + String(WCHAR_MIN, HEX));                //  minimum value of wchar_t
Serial.println("WCHAR_MAX = " + String(WCHAR_MAX, DEC) + ", " + String(WCHAR_MAX, HEX));                //  maximum value of wchar_t
Serial.println("CHAR_BIT = " + String(CHAR_BIT, DEC) + ", " + String(CHAR_BIT, HEX));                   //  number of bits in a char
Serial.println("MB_LEN_MAX = " + String(MB_LEN_MAX, DEC) + ", " + String(MB_LEN_MAX, HEX));             //  maximum length of a multibyte character in bytes
Serial.println("FLT_MIN = " + String(FLT_MIN, DEC) + ", " + String(FLT_MIN, HEX));                      //  smallest normalised positive value of a float
Serial.println("FLT_MAX = " + String(FLT_MAX, DEC) + ", " + String(FLT_MAX, HEX));                      //  largest positive finite value of a float
Serial.println("DBL_MIN = " + String(DBL_MIN, DEC) + ", " + String(DBL_MIN, HEX));                      //  smallest normalised positive value of a double
Serial.println("DBL_MAX = " + String(DBL_MAX, DEC) + ", " + String(DBL_MAX, HEX));                      //  largest positive finite value of a double
Serial.println("LDBL_MIN = " + String(LDBL_MIN, DEC) + ", " + String(LDBL_MIN, HEX));                   //  smallest normalised positive value of a long double
Serial.println("LDBL_MAX = " + String(LDBL_MAX, DEC) + ", " + String(LDBL_MAX, HEX));                   //  largest positive finite value of a long double
Serial.println("FLT_DIG = " + String(FLT_DIG, DEC) + ", " + String(FLT_DIG, HEX));                      //  the number of decimal digits guaranteed to be preserved converting from text to float and back to text
Serial.println("DBL_DIG = " + String(DBL_DIG, DEC) + ", " + String(DBL_DIG, HEX));                      //  the number of decimal digits guaranteed to be preserved converting from text to double and back to text
Serial.println("LDBL_DIG = " + String(LDBL_DIG, DEC) + ", " + String(LDBL_DIG, HEX));                   //  the number of decimal digits guaranteed to be preserved converting from text to long double and back to text

timer.cpp

#include <Arduino.h>

void resetTimerRegisters();
void initialisePrescalerBits();
void initialiseControlBits();
void initialiseTriggerBits();
void initialiseComparisonValues();
void setPrescaler(word scaleFactor);

__attribute__((unused))
void setup() {
    Serial.begin(9600);
    while (!Serial) { }
    Serial.println();
    Serial.println("================");
    Serial.println("Fun With Timers");
    Serial.println("================");
    pinMode(2, OUTPUT);
    noInterrupts();

    resetTimerRegisters();
    initialiseControlBits();
    initialisePrescalerBits();
    initialiseTriggerBits();
    initialiseComparisonValues();

    interrupts();
}

void initialiseComparisonValues() {
    OCR2A = 200;
    OCR2B = 50;
}

void initialiseTriggerBits() {
    TIMSK2 |= _BV(OCIE2A);
    TIMSK2 |= _BV(OCIE2B);
}

void initialiseControlBits() {
    TCCR2A |= _BV(WGM20);
    TCCR2A |= _BV(WGM21);
    TCCR2A |= _BV(COM2A0);
}

void initialisePrescalerBits() {
    setPrescaler(0);
}

void resetTimerRegisters() {
    TCCR2A &= B00001100;
    TCCR2B &= B00110000;
    TIMSK2 &= B11111000;
}

__attribute__((unused))
void loop() {
}

__attribute__((unused))
void serialEvent() {
    if (Serial.available()) {
        String input = Serial.readString();
        Serial.println("Received: \"" + input + "\"");
        char command = input[0];

        switch (command) {
            case 'p':
            case 'P': {
                word scaleFactor = input.substring(1).toInt();
                setPrescaler(scaleFactor);
                break;
            }
            default: {
                Serial.println("Unknown command.");
                break;
            }
        }
    }
}

ISR(TIMER2_COMPA_vect) {
    digitalWrite(2, LOW);
}

ISR(TIMER2_COMPB_vect) {
    digitalWrite(2, HIGH);
}

void setPrescaler(word scaleFactor) {
    Serial.println("Set Prescaler:  " + String(scaleFactor));
    TCCR2B &= B1111000;
    switch (scaleFactor) {
        case 0:
            Serial.println("case 0 (" + String(scaleFactor) + ").  Timer disabled.");
            break;
        case 1:
            Serial.println("case 1 (" + String(scaleFactor) + ").");
            TCCR2B |= _BV(CS20);
            break;
        case 8:
            Serial.println("case 8 (" + String(scaleFactor) + ").");
            TCCR2B |= _BV(CS21);
            break;
        case 64:
            Serial.println("case 64 (" + String(scaleFactor) + ").");
            TCCR2B |= _BV(CS20);
            TCCR2B |= _BV(CS21);
            break;
        case 256:
            Serial.println("case 256 (" + String(scaleFactor) + ").");
            TCCR2B |= _BV(CS22);
            break;
        case 1024:
            Serial.println("case 1024 (" + String(scaleFactor) + ").");
            TCCR2B |= _BV(CS20);
            TCCR2B |= _BV(CS22);
            break;
        default:
            Serial.println("ERROR:  Invalid prescaler factor (" + String(scaleFactor) + ")");
            break;
    }
    Serial.println( "TCCR2B = " + String(TCCR2B, BIN));
}

vectors.cpp

ISR(INT0_vect) {   /* External Interrupt Request 0 */
    Serial.println("INT0_vect");
}

ISR(INT1_vect) {   /* External Interrupt Request 1 */
    Serial.println("INT1_vect");
}

ISR(PCINT0_vect) {   /* Pin Change Interrupt Request 0 */
    Serial.println("PCINT0_vect");
}

ISR(PCINT1_vect) {   /* Pin Change Interrupt Request 0 */
    Serial.println("PCINT1_vect");
}

ISR(PCINT2_vect) {   /* Pin Change Interrupt Request 1 */
    Serial.println("PCINT2_vect");
}

ISR(WDT_vect) {   /* Watchdog Time-out Interrupt */
    Serial.println("WDT_vect");
}

ISR(TIMER2_COMPA_vect) {   /* Timer/Counter2 Compare Match A */
    Serial.println("TIMER2_COMPA_vect");
}

ISR(TIMER2_COMPB_vect) {   /* Timer/Counter2 Compare Match A */
    Serial.println("TIMER2_COMPB_vect");
}

ISR(TIMER2_OVF_vect) {   /* Timer/Counter2 Overflow */
    Serial.println("TIMER2_OVF_vect");
}

ISR(TIMER1_CAPT_vect) {  /* Timer/Counter1 Capture Event */
    Serial.println("TIMER1_CAPT_vect");
}

ISR(TIMER1_COMPA_vect) {  /* Timer/Counter1 Compare Match A */
    Serial.println("TIMER1_COMPA_vect");
}

ISR(TIMER1_COMPB_vect) {  /* Timer/Counter1 Compare Match B */
    Serial.println("TIMER1_COMPB_vect");
}

ISR(TIMER1_OVF_vect) {  /* Timer/Counter1 Overflow */
    Serial.println("TIMER1_OVF_vect");
}

ISR(TIMER0_COMPA_vect) {  /* TimerCounter0 Compare Match A */
    Serial.println("TIMER0_COMPA_vect");
}

ISR(TIMER0_COMPB_vect) {  /* TimerCounter0 Compare Match B */
    Serial.println("TIMER0_COMPB_vect");
}

ISR(TIMER0_OVF_vect) {  /* Timer/Couner0 Overflow */
    Serial.println("TIMER0_OVF_vect");
}

ISR(SPI_STC_vect) {  /* SPI Serial Transfer Complete */
    Serial.println("SPI_STC_vect");
}

//ISR(USART_RX_vect) {  /* USART Rx Complete */
//    Serial.println("USART_RX_vect");
//}

//ISR(USART_UDRE_vect) {  /* USART, Data Register Empty */
//    Serial.println("USART_UDRE_vect");
//}

ISR(USART_TX_vect) {  /* USART Tx Complete */
    Serial.println("USART_TX_vect");
}

ISR(ADC_vect) {  /* ADC Conversion Complete */
    Serial.println("ADC_vect");
}

ISR(EE_READY_vect) {  /* EEPROM Ready */
    Serial.println("EE_READY_vect");
}

ISR(ANALOG_COMP_vect) {  /* Analog Comparator */
    Serial.println("ANALOG_COMP_vect");
}

ISR(TWI_vect) {  /* Two-wire Serial Interface */
    Serial.println("TWI_vect");
}

vectors.md

Vector name	Vector definition
INT0_vect	External Interrupt Request 0
INT1_vect	External Interrupt Request 1
PCINT0_vect	Pin Change Interrupt Request 0
PCINT1_vect	Pin Change Interrupt Request 0
PCINT2_vect	Pin Change Interrupt Request 1
WDT_vect	Watchdog Time-out Interrupt
TIMER2_COMPA_vect	Timer/Counter2 Compare Match A
TIMER2_COMPB_vect	Timer/Counter2 Compare Match A
TIMER2_OVF_vect	Timer/Counter2 Overflow
TIMER1_CAPT_vect	Timer/Counter1 Capture Event
TIMER1_COMPA_vect	Timer/Counter1 Compare Match A
TIMER1_COMPB_vect	Timer/Counter1 Compare Match B
TIMER1_OVF_vect	Timer/Counter1 Overflow
TIMER0_COMPA_vect	TimerCounter0 Compare Match A
TIMER0_COMPB_vect	TimerCounter0 Compare Match B
TIMER0_OVF_vect	Timer/Couner0 Overflow
SPI_STC_vect	SPI Serial Transfer Complete
USART_RX_vect	USART Rx Complete
USART_UDRE_vect	USART, Data Register Empty
USART_TX_vect	USART Tx Complete
ADC_vect	ADC Conversion Complete
EE_READY_vect	EEPROM Ready
ANALOG_COMP_vect	Analog Comparator
TWI_vect	Two-wire Serial Interface
SPM_READY_vect	Store Program Memory Read