Problem s LCD 16x2

[Pavel Kutina]

RW je na zemi.

Prochazim si ted ten kod, soucasne s datasheetem od toho radice a uz mam v 
hlave totalni gulas.

Uz jsem z toho tak pitomej, ze si to rozepisuju "absolutne" jako sekvenci 
Out prikazu po bitech:

delay_ms(300);
PORTB := %00100100;
PORTB := %00100000;

atd.

ovšem "výhoda" je, že se mi zatím ani jedním způsobem nepodařilo 
inicializovat ani ten 2x8 (jinak funkční) displej, takže tohle bude zcela 
jistě v rukách :)

Pavel Kutina


----- Original Message ----- 
From: "Jan Waclawek" <konfera@efton.sk>
To: "HW-news" <hw-list@list.hw.cz>
Sent: Wednesday, September 16, 2009 6:27 PM
Subject: Re: Problem s LCD 16x2


A RW?

Predpokladajuc, ze RW je na PORTB.1

var portBShdw: byte;
    dummy: byte;

procedure PulseE;
begin
  portBShdw :=  portBShdw AND 0xF7;  { E up }
  PORTB := portBShdw;
  Delay_us(1);
  portBShdw :=  portBShdw OR  0x08;  { E down }
  PORTB := portBShdw;
end;

procedure OutNibble(b: byte);
begin
  portBShdw := portBShdw AND 0xFB;  { RS down }
  PORTB := portBShdw;
  portBShdw := (portBShdw AND 0x0F) OR b;  { data }
  PORTB := portBShdw;
  PulseE;
  portBShdw := portBShdw OR  0x04;  { RS up }
  PORTB := portBShdw;
end;

procedure DisplayWriteCommand(b: byte);
begin
  portBShdw := portBShdw AND 0xFB;  { RS down }
  PORTB := portBShdw;
  portBShdw := (portBShdw AND 0x0F) OR (b SHL 4);  { lower data }
  PORTB := portBShdw;
  PulseE;
  portBShdw := (portBShdw AND 0x0F) OR (b AND 0xF0);  { upper data }
  PORTB := portBShdw;
  PulseE;
  portBShdw := portBShdw OR  0x04;  { RS up }
  PORTB := portBShdw;
end;

function DisplayReadStatus: byte;
begin
               ----- sem musi prist nieco co sposobi, ze horne bity portu 
budu citatelne
  portBShdw := portBShdw AND 0xFB;  { RS down }
  portBShdw := portBShdw OR  0x02;  { WR up }
  PORTB := portBShdw;
  portBShdw :=  portBShdw AND 0xF7;  { E up }
  PORTB := portBShdw;
  Delay_us(1);
  DisplayReadStatus := PORTB; ----- toto samozrejme takto asi nepojde... vid 
zaciatok rutiny
  portBShdw :=  portBShdw OR  0x08;  { E down }
  PORTB := portBShdw;
  portBShdw := portBShdw AND 0xFD;  { WR down }
  portBShdw := portBShdw OR  0x04;  { RS up }
  PORTB := portBShdw;
                ----- teraz treba nastavit znova tie horne bity na zapis
end;

{main} begin
  portBShdw := 0xFF;
  PORTB := PortBShdw;
  Delay_m(100);     { initial wait until LCD resets itself }

  portBShdw := portBShdw AND 0xF5;  { E and RW down  - we are going to write 
to registers now}
  OutNibble(0x30);
  Delay_m(10);
  OutNibble(0x30);
  Delay_m(1);
  OutNibble(0x30);
  Delay_m(1);

  OutNibble(0x20);
  Delay_m(1);

  dummy := DisplayReadStatus;  {black magic, but if there is no read in the 
8-bit mode, some of the commands get not executed until this is called... 
and characters are not written correctly...}

  DisplayWriteCommand(0x08);               // 0000 1000  (Display off)
  Delay_m(1);
  DisplayWriteCommand(0x01);               // 0000 0001  (Display clear)
  Delay_m(2);
  DisplayWriteCommand(0x02);               // 0000 0010  (Cursor home)
  Delay_m(2);
  DisplayWriteCommand(0x06);               // 0000 0110  (Entry Mode Set: 
increment, no shift)
  Delay_m(1);
  DisplayWriteCommand(0x0C);               // 0000 1100  (Display on)
  Delay_m(1);

--- a sem pride nejaky normalny vypis

end;


Pochopitelne to nemam ako vyskusat, mozno som tam urobil aj nejake chyby, 
ale na uvod takto nejako.


wek

----- Original Message ---------------
>na porty jednoduse:
>
>na cely port:
>PORTB := 0xff;
>na bit
>PORTB.1 := _TRUE;
>
>displej visi takhle:
>LCD_RS : PORTB.2
>LCD_EN : PORTB.3;
>
>LCD_D4 : PORTB.4;
>LCD_D5 : PORTB.5;
>LCD_D6 : PORTB.6;
>LCD_D7 : PORTB.7;
>
>delay:
>sto mikrosekund:
>Delay_us(100);
>sto milisekund:
>Delay_m(100);
>
>

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