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

#include "lcd.h"

static inline void LCDInitPorts(void)
{
#ifdef LCD4
    //<4-bit interface port initialization>
    DDRB|=_BV(1);
    DDRB|=_BV(0);
    DDRD|=_BV(7);
    DDRD|=_BV(6);
#else
    //<8-bit interface port initialization>
#endif

    RS_DDR|=_BV(RS_PIN);
    RW_DDR|=_BV(RW_PIN);
    EN_DDR|=_BV(EN_PIN);
}

static inline void LCDBus(unsigned char data)
{
#ifdef LCD4
    //<4-bit interface bus output>
    ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
    {
        unsigned char a=PORTD;
        a&=0x3F;
        a|=(data<<6)&0xC0;

        unsigned char b=PORTB;
        b&=0xFC;
        b|=(data>>2)&0x03;

        PORTD=a;
        PORTB=b;
    }
#else
    //<8-bit interface bus output>
#endif
}

static inline void RS(unsigned char value)
{
    if(value)RS_PORT|=_BV(RS_PIN);
    else RS_PORT&=~_BV(RS_PIN);
}

static inline void RW(unsigned char value)
{
    if(value)RW_PORT|=_BV(RW_PIN);
    else RW_PORT&=~_BV(RW_PIN);
}

static inline void EN(unsigned char value)
{
    if(value)EN_PORT|=_BV(EN_PIN);
    else EN_PORT&=~_BV(EN_PIN);
}

#ifdef LCD4
static void LCDWriteHalfByte(unsigned char data)
{
    RS(0);
    RW(0);
    EN(1);
    LCDBus(data&0x0F);
    _delay_us(1);
    EN(0);
}
#endif

static void LCDWriteByte(unsigned char data)
{
    RW(0);

#ifdef LCD4
    EN(1);
    LCDBus((data&0xF0)>>4); //high nibble
    _delay_us(1);
    EN(0);

    _delay_us(1);

    EN(1);
    LCDBus(data&0x0F); //low nibble
    _delay_us(1);
    EN(0);

#else
    EN(1);
    LCDBus(data);
    _delay_us(1);
    EN(0);
#endif
}

void LCDCommand(unsigned char cmd)
{
    RS(0);
    LCDWriteByte(cmd);
}

void LCDData(unsigned char data)
{
    RS(1);
    LCDWriteByte(data);
}

void LCDBusy(void)
{
    _delay_us(70);
}

void LCDInit(void)
{
    LCDInitPorts();

#ifdef LCD4
    _delay_ms(20);
    LCDWriteHalfByte(0x03);
    _delay_ms(5);
    LCDWriteHalfByte(0x03);
    _delay_us(120);
    LCDWriteHalfByte(0x03);
    _delay_ms(5);
    LCDWriteHalfByte(0x02);
    _delay_ms(3);
    LCDCommand(0x28);
    _delay_ms(3);
    LCDCommand(0x08);
    _delay_ms(3);
    LCDCommand(0x01);
    _delay_ms(3);
    LCDCommand(0x06);
    _delay_ms(3);
    LCDCommand(0x0c);
#else
    _delay_ms(20);
    LCDCommand(0x38);
    _delay_ms(5);
    LCDCommand(0x38);
    _delay_us(120);
    LCDCommand(0x38);
    _delay_ms(3);
    LCDCommand(0x38);
    _delay_ms(3);
    LCDCommand(0x08);
    _delay_ms(3);
    LCDCommand(0x01);
    _delay_ms(3);
    LCDCommand(0x06);
    _delay_ms(3);
    LCDCommand(0x0c);
#endif
}

void LCDWriteString(char* str, unsigned char strLen)
{
    for(unsigned char i=strLen;i;i--)
    {
        LCDBusy();
        LCDData(*str++);
    }
}

void LCDWriteStringZ(char* str)
{
    while(*str)
    {
        LCDBusy();
        LCDData(*str++);
    }
}