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#define G_BASE 0x0300   // grafiikkamuistin base address
#define T_BASE 0x0000   // tekstimuistin base address
#define BYTES_PER_ROW 40 // merkkiä rivillä

#define BASE 0x378      // lpt portin osoite

void WaitDisplayReady(void)
// reads the display status byte and checks
// that the display is ready before writing

// doesn't have any check in case the status byte
// can't be read so this situation may cause a lockup

{
 
  int Tmp;

       Tmp = DlPortReadPortUshort(BASE + 0x402);
       Tmp = Tmp & 0x1F;
       Tmp = Tmp | 0x20;
       DlPortWritePortUshort(BASE + 0x402, Tmp);

       do{
             DlPortWritePortUshort(BASE + 2, 0x20 + 4 + 2);     //In, CD=1, CS=0, Wr=1
             DlPortWritePortUshort(BASE + 2, 0x20 + 4 + 2 + 8); //In, CD=1, CS=0, Wr=1, Rd=0
             Tmp = DlPortReadPortUshort(BASE);
             DlPortWritePortUshort(BASE + 2, 0x20 + 4 + 2);     //In, CD=1, CS=0, Wr=1

       }while ((Tmp & 3) != 3 );
       DlPortWritePortUshort(BASE + 2, 0);
   
}

void WriteData(USHORT Data)
{

    /* pollin
   WaitDisplayReady();
    DlPortWritePortUshort(BASE + 2, 0);   // 0111 C/D low
    DlPortWritePortUshort(BASE + 2, 2);   // 0011 WR low
    DlPortWritePortUshort(BASE, Data);
    DlPortWritePortUshort(BASE + 2, 3);   // 0010 CE low
    DlPortWritePortUshort(BASE + 2, 2);   // 0011 CE high
    DlPortWritePortUshort(BASE + 2, 0);   // 0111 WR high
   */

   /* powerlcd */
   DlPortWritePortUshort(BASE + 2, 0x0c);   // 0111 C/D low
   DlPortWritePortUshort(BASE + 2, 0x08);   // 0011 WR low
   DlPortWritePortUshort(BASE, Data);
   DlPortWritePortUshort(BASE + 2, 0x09);   // 0010 CE low
   DlPortWritePortUshort(BASE + 2, 0x08);   // 0011 CE high
   DlPortWritePortUshort(BASE + 2, 0x0c);   // 0111 WR high
   
}

void WriteCtrl(USHORT Command)
{

   /*
   WaitDisplayReady();
    DlPortWritePortUshort(BASE, Command);
    DlPortWritePortUshort(BASE + 2, 4);      // 1111 C/D high
    DlPortWritePortUshort(BASE + 2, 4+2);      // 1011 WR low
    DlPortWritePortUshort(BASE + 2, 4+3);      // 1010 CE low
    DlPortWritePortUshort(BASE + 2, 4+2);      // 1011 CE high
    DlPortWritePortUshort(BASE + 2, 0);      // 0111 C/D low
   */

   /* powerlcd */
   DlPortWritePortUshort(BASE + 2, 0x04);      // 1111 C/D high
   DlPortWritePortUshort(BASE + 2, 0x00);      // 1011 WR low
   DlPortWritePortUshort(BASE, Command);
   DlPortWritePortUshort(BASE + 2, 0x01);      // 1010 CE low
   DlPortWritePortUshort(BASE + 2, 0x00);      // 1011 CE high
   DlPortWritePortUshort(BASE + 2, 0x0c);      // 0111 C/D low
}

void InitLCD(void)
{
  // Display init
  WriteData(T_BASE & 0xFF);   // Data1: LowAddress
  WriteData(T_BASE >> 8);     // Data2: HighAddress
  WriteCtrl(0x40);            // Command: 0x40 -> 01000000

  WriteData(BYTES_PER_ROW);  // Data1: Colums
  WriteData(0);              // Data2: 0
  WriteCtrl(0x41);           // Command: 0x41 -> 01000001

  WriteData(G_BASE & 0xFF);  // Data1: LowAddress
  WriteData(G_BASE >> 8);    // Data2: HighAddress
  WriteCtrl(0x42);           // Command: 0x42 -> 01000010

  WriteData(BYTES_PER_ROW);  // Data1: Colums
  WriteData(0);              // Data2: 0
  WriteCtrl(0x43);           // Command: 0x43 -> 01000011

  // Internal CGROM Mode, OR Mode
  WriteCtrl(0x80); // OR Mode    // 80->10000000

  WriteCtrl(0xa7); // cursor is 8 lines high
  WriteData(0x00);
  WriteData(0x00);
  WriteCtrl(0x21); // put cursor at (x,y)

  // DisplayMode
  WriteCtrl(0x9D);
}

void SetLCDXY(int x, int y)
{
int addr;
  addr = T_BASE + (y * BYTES_PER_ROW) + x;
  WriteData(addr & 0xFF);
  WriteData(addr >> 8);
  WriteCtrl(0x24);
}

void SetLCDCursor(int x, int y)
{
  WriteData(x);
  WriteData(y);
  WriteCtrl(0x21);
}

void ClearLCDText(void)
{
  int i;

  WriteData(T_BASE & 0xFF);
  WriteData(T_BASE >> 8);
  WriteCtrl(0x24);      // address pointer to T_BASE

  for (i=0;i<640;i++) {
        WriteData(0); WriteCtrl(0xc0); // write data and inc ptr
  }
}

void ClearLCDGraph(void)
{
  int i;

  WriteData(G_BASE & 0xFF);
  WriteData(G_BASE >> 8);
  WriteCtrl(0x24); // address pointer to G_BASE

  for (i=0;i<5120;i++){
        WriteData(0); WriteCtrl(0xc0); // write data and inc ptr
  }
}

void PrintLCDText(char *string)
{
  unsigned int i;
  char c;

  for (i=0;i<strlen(string);i++){
        c = string[i] - 0x20; // conversion from ASCII to LCD characters
        if (c<0) c=0;
        WriteData(c);
        WriteCtrl(0xc0);
  }
}

void SetLCDPixel(int x, int y)
{
  int addr;

  addr = G_BASE + (y*BYTES_PER_ROW) + (x/6);
  WriteData(addr & 0xFF);
  WriteData(addr >> 8);
  WriteCtrl(0x24);
  WriteCtrl(0xf8 | (5-(x % 6)));
}

void ClearLCDPixel(int x, int y)
{
  int addr;

  addr = G_BASE + (y*BYTES_PER_ROW) + (x/6);
  WriteData(addr & 0xFF);
  WriteData(addr >> 8);
  WriteCtrl(0x24);
  WriteCtrl(0xf0 | (5-(x % 6)));
}


void main(void)
{
  InitLCD();
  ClearLCDText();
  ClearLCDGraph();
  SetLCDXY(2,7);
  PrintLCDText("Text juttu lisaa");

  for(int i=0;i<240;i++)
     for(int j=10;j<50;j++)
         SetLCDPixel(i,j);
 
  for(int k=110;k<150;k++)
     for(int l=20;l<30;l++)
        ClearLCDPixel(k,l);

  for(int m=10;m<20;m++)
     for(int n=20;n<30;n++)
        ClearLCDPixel(m,n);

}