TOPIC:

...
const
  E_PULSE = 50; //usec
  E_DELAY = 50; //usec
   
  LCD_CHR = 1;
  LCD_CMD = 0;

   lcd_alignLeft   = 0;
   lcd_alignCenter = 1;
   lcd_alignRight  = 2;

  LCD_LINE_1 = $00; //$80; // LCD RAM address for the 1st line
  LCD_LINE_2 = $40; //$C0; // LCD RAM address for the 2nd line
  LCD_LINE_3 = $14; //$94; // LCD RAM address for the 3rd line
  LCD_LINE_4 = $54; //$D4; // LCD RAM address for the 4th line
 
  lcd_init_array: array [0..3] of byte = (
   $28,  // Set mode: 4-bit, 2+ lines, 5x8 dots
   $0C,  // Display on
   $01,  // Clear display
   $06);
           
...
procedure pi_board_Write(addr: byte; reg: word; value: byte; const LowCS: Boolean = True; const HighCS: Boolean = True);
begin
 if LowCS then
  gpio_set_pin(gpio_pi_CS_23S17, output_Low); //gpio_pi_CS_23S17 is my chip-select PIN
  //Sleep(50);
 try
   //SPI_Write(addr or rpi_SPI_SLAVE_WRITE, reg, value);
  if LowCS then
		 SPI_Write_Byte(0, addr);
		 SPI_Write_Byte(0, reg);
		 SPI_Write_Byte(0, value);
 finally
  if HighCS then
   gpio_set_pin(gpio_pi_CS_23S17, output_High);
   //Sleep(50);
 end;
end;

procedure lcd_byte(bits: byte; mode: byte); //a low level function, see LCD_SendStringXY below
var data: byte;
begin
  // Send byte to data pins
  // bits = data
  // mode = True  for character
  //        False for command

  data:=mode;
 if LCD_BackLight_On then data:=data or $08   // %0000 1000
                     else data:=data and $F7; // %1111 0111
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//False); //RS

  // High bits
  //data:=0;
 if bits and $10 = $10 then data:=data or $10;
 if bits and $20 = $20 then data:=data or $20;
 if bits and $40 = $40 then data:=data or $40;
 if bits and $80 = $80 then data:=data or $80;

  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, False); //High bits

  // toggle Enable bit
  delay_us(E_DELAY);
  data:=data or LCD_EN;
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, False); //High bits
  delay_us(E_PULSE);
  data:=data and (255 - LCD_EN); //zero bit LCD_EN = 2
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, False); //High bits
  delay_us(E_DELAY);

  // Low bits
  data:=data and $0F; //zero high 4 bits
 if bits and $1 = $1 then data:=data or $10;
 if bits and $2 = $2 then data:=data or $20;
 if bits and $4 = $4 then data:=data or $40;
 if bits and $8 = $8 then data:=data or $80;

  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, False); //High bits

  // toggle Enable bit
  delay_us(E_DELAY);
  data:=data or LCD_EN;
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, False); //High bits
  delay_us(E_PULSE);
  data:=data and (255 - LCD_EN); //zero bit LCD_EN = 2
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, data, True, True);//, False, True); //High bits
  delay_us(E_DELAY);
end;

procedure LCD_Init;
var I: Integer;
begin
  pi_board_Write(rpi_SPI_SLAVE_ADDR, GPIOB, 0); //High bits
  lcd_byte($00, LCD_CMD);
 for I:=0 to 2 do
   begin
     lcd_byte($03, LCD_CMD);
     delay_msec(5);
   end;
   lcd_byte($02, LCD_CMD);
  delay_msec(35);
 for I:=0 to 3 do //currently 4-line display
   begin
     lcd_byte(LCD_Init_Array[I], LCD_CMD);
     delay_msec(50);
   end;
end;
procedure LCD_SendStringXY(X, Y: byte; what: ansistring; const align_: byte = lcd_alignLeft);
var b, c: byte;
    I: Integer;
begin
  b:=LCD_LINE_1;
 case y of
   2: b:=LCD_LINE_2;
   3: b:=LCD_LINE_3;
   4: b:=LCD_LINE_4;
 end;

  b:=b + x - 1;
  lcd_byte($80 or b, LCD_CMD);

  c:=Length(what);
 if c > 20 then what:=Copy(what, 1, 20);

 if c < 20 then
   begin
    if align_ = lcd_alignLeft then what:=what + StringOfChar(' ', 20 - c)
    else
    if align_ = lcd_alignRight then what:=StringOfChar(' ', 20 - c) + what
    else
      begin //align_ = lcd_alignCenter
       if c mod 2 <> 0 then //odd count of string chars
         begin
           what:=what + ' ';
           c:=Length(what);
         end;
        c:=(20 - c) div 2;
        what:=StringOfChar(' ', c) + what + StringOfChar(' ', c);
      end;
   end;

 for I:=1 to Length(what) do
   begin
     b:=Ord(What[I]);
     lcd_byte(b, LCD_CHR);
   end;
end;