/*
Author: Torben Hellige t . hellige [ at ] web.de

This file is used to demonstrate the interface to NKK 36x24px SmartSwitches

Tested with NKK IS-15F2

This code it just bitbanging the interface. This is not useful for any type of production code.
The clock has to be stable, otherwise flicker might occure.

*/

#include <avr/io.h>
#include <util/delay.h>

#define FLM 2
#define LP  3
#define SCP 4
#define DIN 5

#define NKK_PORT PORTD
#define NKK_DDR DDRD

uint8_t data[24][36];

void main(void)
{
    NKK_DDR |= (1<<FLM) | (1<<LP) | (1<<SCP) | (1<<DIN);

    for(int y=0; y<24; y++)
    {
        for(int x=0; x < 36; x++)
        {
            data[y][x] = 0;
        }
    }

    //Set test pattern
    for(int i=0; i < 36; i++)
    {
        data[0][i] = 1;
        data[23][i] = 1;
    }

    for(int i=0; i < 24; i++)
    {
        data[i][0] = 1;
        data[i][35] = 1;
    }

    data[12][18] = 1;
    data[11][18] = 1;
    data[13][18] = 1;
    data[12][17] = 1;
    data[12][19] = 1;

    while(1)
    {

        //Start image frame
        NKK_PORT |= (1<<SCP);
        NKK_PORT |= (1<<FLM);   
        _delay_us(1);
        for(uint8_t y = 0; y < 24; y++)
        {
            NKK_PORT |= (1<<LP);
            _delay_us(1);

            NKK_PORT &= ~(1<<SCP);

            _delay_us(1);

            NKK_PORT &=~(1<<LP);
            _delay_us(1);
            
            NKK_PORT &=~(1<<FLM);
            _delay_us(1);

            for(uint8_t x = 0; x < 40; x++)
            {
                NKK_PORT &= ~(1<<SCP);
                _delay_us(10);

                //Correct Y axis 
                //For some reason it will send the second line first and the first line at the end
                uint8_t real_y;
                real_y = y+1;

                if(real_y > 23)
                    real_y = 0;


                if(x >= 4 && data[real_y][x-4])
                    NKK_PORT |= (1<<DIN); //RAM Data here
                else
                    NKK_PORT &=~(1<<DIN); //RAM Data here


                NKK_PORT |= (1<<SCP);
                _delay_us(10);
            }

        }
    }
}