cd334

/***********************************************************************
 *  timi_cd.c
 *  ATmega16A C only timer handling
 *  by tovis + cd334 2015
 *  Really simple code for ATmega16A timer0
 *  Good: OC0 pin (DIP40/4) gives nice 1KHz square wave signal.
 *  Bad:  PORTA bit 0 (DIP40/40) shows that every fourth interrupt
 *        too sort (bit after toggle quickly toggle back).
 *        No square wave, every fourth toggle is too sort.
***********************************************************************/
#include  <avr/io.h>
#include  <avr/interrupt.h>



//----------------------------------------------------------------------
#define F_CPU           16000000ul      // ATmega16A external crystal 16MHz

#define SETBIT(ADDRESS,BIT) (ADDRESS |= (1<<BIT))
#define CLEARBIT(ADDRESS,BIT) (ADDRESS &= ~(1<<BIT))
#define FLIPBIT(ADDRESS,BIT) (ADDRESS ^= (1<<BIT))

//----------------------------------------------------------------------

volatile uint8_t int_source = 0x00;

ISR(BADISR_vect)
{
    PORTA = 0xFF;
    for(;;);
}

// Interrupt source debug on PORTA Pin 1 to 5
// All ISR vector is defined

ISR(INT0_vect)
{
    int_source = 0x01;
    PORTA = int_source << 1;
    for(;;);
}

ISR(INT1_vect)
{
    int_source = 0x02;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER2_COMP_vect)
{
    int_source = 0x03;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER2_OVF_vect)
{
    int_source = 0x04;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER1_CAPT_vect)
{
    int_source = 0x05;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER1_COMPA_vect)
{
    int_source = 0x06;
    PORTA = int_source << 1;
    for(;;);
}
ISR(TIMER1_COMPB_vect)
{
    int_source = 0x07;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER1_OVF_vect)
{
    int_source = 0x08;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER0_OVF_vect)
{
    int_source = 0x09;
    PORTA = int_source << 1;
    for(;;);
}

ISR(SPI_STC_vect)
{
    int_source = 0x0A;
    PORTA = int_source << 1;
    for(;;);
}

ISR(USART_RXC_vect)
{
    int_source = 0x0B;
    PORTA = int_source << 1;
    for(;;);
}

ISR(USART_UDRE_vect)
{
    int_source = 0x0C;
    PORTA = int_source << 1;
    for(;;);
}

ISR(USART_TXC_vect)
{
    int_source = 0x0D;
    PORTA = int_source << 1;
    for(;;);
}

ISR(ADC_vect)
{
    int_source = 0x0E;
    PORTA = int_source << 1;
    for(;;);
}

ISR(EE_RDY_vect)
{
    int_source = 0x0F;
    PORTA = int_source << 1;
    for(;;);
}

ISR(ANA_COMP_vect)
{
    int_source = 0x10;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TWI_vect)
{
    int_source = 0x11;
    PORTA = int_source << 1;
    for(;;);
}

ISR(INT2_vect)
{
    int_source = 0x12;
    PORTA = int_source << 1;
    for(;;);
}

ISR(TIMER0_COMP_vect)
{
    FLIPBIT(PORTA,0);
}

ISR(SPM_RDY_vect)
{
    int_source = 0x13;
    PORTA = int_source << 1;
    for(;;);
}

// Interrupt source debug on PORTA Pin 1 to 5

//----------------------------------------------------------------------
int             main(void)
{

  DDRA   = 0xFF;                        // whole PORTA set as output
  PORTA  = 0x00;
  TCCR0  = 0x1B;                        // Timer0 CTC mode:
                                        // using internal clock,
                                        // prescaler 1/64, toggle OC0

  OCR0   = 250;                         // Set compare register for 1ms

  TIFR   = 0xFF;                        // Clear pending interrupts
  TIMSK  = 0x02;                        // Timer interrupt setting, only OCR0 enabled

  DDRB = 0x80;                          //OC0 pin to output
  PORTB = 0x00;                         //give initial port value;

  //---
  sei();                                // Enbale all interrupts
  while ( 1 )                           // Loop forever
  {
    FLIPBIT(PORTA,7);               // Toggle port A pin 7
  }
}
/*** OLD MAIN function) ***/
/*
int             main(void)
{
  DDRA   = 0xFF;                        // whole PORTA set as output
  TCCR0  = 0x1B;                        // Timer0 CTC mode:
                                        // using internal clock,
                                        // prescaler 1/64, toggle OC0
  OCR0   = 250;                         // Set compare register for 1ms
  TIFR   = 0;                           // Clear pending interrupts
  TIMSK &= ~(1 << TOIE0);               // Disable Timer0 overflow interrupt
  TIMSK |= (1 << OCIE0);                // Enable timer 0 compare match interrupt
  DDRB   = (1 << 3);                    // ??? set PORTB, OC0 pin to output
  //---
  sei();                                // Enbale all interrupts
  while ( 1 )                           // Loop forever
  {
    PORTA = PINA ^ 0x80;                // Toggle port A pin 7
  }
*/

/***********************************************************************
 *  end timi_cd.c
***********************************************************************/