NESRGBSwitch.c

/*
 * File:   NESRGBSwitch.c
 * Author: Ben Whitman
 *
 * PIC10F322
 *
 * Created on April 2, 2015, 6:33 PM
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <xc.h>

#include "HEFlash.h"

// CONFIG
#pragma config FOSC = INTOSC    // Oscillator Selection bits (INTOSC oscillator: CLKIN function disabled)
#pragma config BOREN = ON       // Brown-out Reset Enable (Brown-out Reset enabled)
#pragma config WDTE = OFF       // Watchdog Timer Enable (WDT disabled)
#pragma config PWRTE = ON       // Power-up Timer Enable bit (PWRT enabled)
#pragma config MCLRE = OFF      // MCLR Pin Function Select bit (MCLR pin function is digital input, MCLR internally tied to VDD)
#pragma config CP = OFF         // Code Protection bit (Program memory code protection is disabled)
#pragma config LVP = OFF        // Low-Voltage Programming Enable (High-voltage on MCLR/VPP must be used for programming)
#pragma config LPBOR = ON       // Brown-out Reset Selection bits (BOR enabled)
#pragma config BORV = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config WRT = OFF        // Flash Memory Self-Write Protection (Write protection off)


uint8_t input_state = 1;
uint8_t output_state = 0;
uint8_t shift_reg = 0xFF;

void button_pressed();
void button_released();
void switch_output();
void save_selection();

/*
 *
 */
int main(int argc, char** argv) {

    OSCCON = 0x00;
    INTCON = 0x00;

    OPTION_REGbits.nWPUEN = 0;
    OPTION_REGbits.T0CS = 0;
    OPTION_REGbits.PSA = 0;
    OPTION_REGbits.PS0 = 1;
    OPTION_REGbits.PS1 = 1;
    OPTION_REGbits.PS2 = 1;

    TRISA = 0x0F;
    LATA = 0x00;
    WPUA = 0x08;
    ANSELA = 0x00;

    INTCONbits.TMR0IF = 0;
    INTCONbits.TMR0IE = 0;
    INTCONbits.GIE = 0;

    HEFLASH_readBlock (&output_state, (HEFLASH_MAXROWS - 1), 1);

    while(1)
    {
        shift_reg = (shift_reg << 1) | PORTAbits.RA3;

        switch(input_state)
        {
            case 0:
                if(shift_reg == 0xFF)
                {
                    input_state = 1;
                    button_released();
                }
                break;

            case 1:
                if(shift_reg == 0x00)
                {
                    input_state = 0;
                    button_pressed();
                }
                break;

            default:
                input_state = PORTAbits.RA3;
        }

        switch(output_state)
        {
            case 0: // Natural palette: 011
                TRISA = 0x0B;
                break;

            case 1: // Improved palette: 101 | 001
                TRISA = 0x0D;
                break;

            case 2: // Garish palette: 110 | 010
                TRISA = 0x0E;
                break;

            case 3: // Composite out
                TRISA = 0x0F;
                break;

            default: // Natural palette
                TRISA = 0x0B;
        }
    }

    return (EXIT_SUCCESS);
}

void button_pressed()
{
    TMR0IF = 0;
    TMR0 = 239;
}


void button_released()
{
    if(TMR0IF)  // Long press
    {
        save_selection();
    }

    else  // Short press
    {
        switch_output();
    }
}


void switch_output()
{
    if(output_state++ > 2) // State 3 = NESRGB disabled/PPU component out
    {
        output_state = 0;
    }
}


void save_selection()
{
    char ret = HEFLASH_writeBlock ((HEFLASH_MAXROWS - 1), &output_state, 1);
}