/*
 * ATmega8A Pin Cycling Test
 * Version 1: Array in Flash (PROGMEM)
 *
 * Cycles through PB0–PB5, PC0–PC5, PD0–PD7.
 * Every 200 ms: one pin is driven low, then returned to input with pull-up,
 * then the next pin is selected.
 *
 * Same as version 2, but lookup table stored in program memory.
 * Uses pgm_read_word() to fetch DDR/PORT addresses and mask.
 */

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <avr/pgmspace.h>
#include <stdint.h>

typedef struct {
    uint16_t ddrAddr;
    uint16_t portAddr;
    uint8_t mask;
} PinDesc;

// --- Array of test pins in flash (PROGMEM) ---
// Use addresses cast to uint16_t
const PinDesc PROGMEM testPins[] = {
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB0) },
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB1) },
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB2) },
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB3) },
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB4) },
    { (uint16_t)&DDRB, (uint16_t)&PORTB, _BV(PB5) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC0) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC1) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC2) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC3) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC4) },
    { (uint16_t)&DDRC, (uint16_t)&PORTC, _BV(PC5) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD0) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD1) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD2) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD3) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD4) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD5) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD6) },
    { (uint16_t)&DDRD, (uint16_t)&PORTD, _BV(PD7) }
};

#define NUM_PINS (sizeof(testPins)/sizeof(testPins[0]))

volatile uint8_t currentPin = 0;
volatile uint8_t toggleState = 0;

ISR(TIMER1_COMPA_vect)
{
	//PORTB ^= _BV(PB0); // toggle PB0
    // Fetch PinDesc from flash
    uint16_t ddrAddr  = pgm_read_word(&testPins[currentPin].ddrAddr);
    uint16_t portAddr = pgm_read_word(&testPins[currentPin].portAddr);
    uint8_t mask      = pgm_read_byte(&testPins[currentPin].mask);

    volatile uint8_t *ddr  = (volatile uint8_t*)ddrAddr;
    volatile uint8_t *port = (volatile uint8_t*)portAddr;

    if (toggleState == 0) {
        *ddr  |= mask;   // output
        *port &= ~mask;  // drive low
        toggleState = 1;
    } else {
        *ddr  &= ~mask;  // input
        *port |= mask;   // pull-up
        currentPin++;
        if (currentPin >= NUM_PINS) currentPin = 0;
        toggleState = 0;
    }
}

static void pins_init(void)
{
    DDRB = 0x00; DDRC = 0x00; DDRD = 0x00;
    PORTB = 0xFF; PORTC = 0xFF; PORTD = 0xFF;
    /*DDRB |= _BV(PB0);  // PB0 output
    PORTB &= ~_BV(PB0);*/
}

static void timer1_init(void)
{
    //TCCR1A = 0;
    TCCR1B = (1 << WGM12) | (1 << CS12);
    //TCNT1 = 0;
    OCR1A = 12500 - 1;
    TIMSK |= (1 << OCIE1A);
}

int main(void)
{
    pins_init();
    timer1_init();
    sei();

    set_sleep_mode(SLEEP_MODE_IDLE);
    for (;;) sleep_mode();
}