KS0066U oder Ähnliche --- LCD Treiber

; ******************************************************************

;    L C D    D I S P L A Y    D E M O

; ******************************************************************

;

;   Provides the entry point for a simple "Hello World" impelmentation

;   using my LCD routines.

;

;   Author:   Adam Swann 

;   Homepage: http://www.velocity2.com/~adam/

;

;   http://www.adamswann.com/projects/avr-lcd/

;

;   See LCD.asm for more information.

;

; ******************************************************************

  .nolist

  .include "m8def.inc"

;  .include "m48def.inc"

  .list

  .cseg

.def   Temp      = r16

.def   Temp2     = r17

; Define generic port names (change the 'A' to whatever you're using)

.equ  LCD_PORT  = PORTD

.equ  LCD_DDR    = DDRD

.equ  LCD_PIN    = PIND

; Define the pin numbers

.equ  LCD_E    = 1

.equ  LCD_RW    = 2

.equ  LCD_RS    = 3

.def  DelayTime = r20

.equ  DelayCount1 = 128

    .org  0

    rjmp  RESET

RESET:  ldi     Temp, low(RAMEND)

      out     SPL, Temp

      ldi     Temp, high(RAMEND)

      out     SPH, temp    ; Initialize Stackpointer

    ldi     Temp, 0x00

    out     LCD_PORT, Temp     ; Clear the outputs

    ldi     Temp, 0xFF

    out     LCD_DDR, Temp     ; Set the direction to output

    ldi     DelayTime, 255    ; Set the default delay length

            ; (see my delay.asm)

    rcall  LCD_Init

    rcall   DELAY

    ldi     r30, low(strInit1*2)

    ldi     r31, high(strInit1*2)

    ldi     Temp2,  20

    rcall  LCD_PrintPM

    ; *** Send the cursor to beginning of second line

    ldi     Temp, 0b11000000

    rcall   LCD_SendCmd

    ldi     r30, low(strInit2*2)

    ldi     r31, high(strInit2*2)

    ldi     Temp2,  20

    rcall  LCD_PrintPM

    rcall   DELAY

FOREVER:  rjmp   FOREVER

strInit1:  .db  "Hello World!        "

strInit2:  .db  "It worked!!!        "

.include "lcd-routines.asm"

; ******************************************************************

;    L C D    D I S P L A Y    R O U T I N E S

; ******************************************************************

;

;   Interfaces the AVR '8515 microcontroller with LCDs controlled

;   by the Samsung KS0066U (and similiar) LCD driver.

;

;   Author:   Adam Swann 

;   Homepage: http://www.velocity2.com/~adam/

;

;   The code below is fairly straightforward and well-documented.

;   See my Web site or e-mail me if you need further instructions.

;

;   I used an 8515 at 4 MHz.  My LCD is Jameco Part #171715.

;

;  Addendum: The Code is also tested on AtMega8 and AtMega48

;  (by cosmicos at gmx.net)

;

;   I wired the LCD display as follows (onto Port D)

;     AVR   LCD

;      0 --> no connection

;      1 --> Enable on LCD

;      2 --> R/W on LCD

;      3 --> RS on LCD

;      4 --> Data4

;      5 --> Data5

;      6 --> Data6

;      7 --> Data7

;

;   References: (URLs may be wrapped)

;    o KS0066U Datasheet 

;

; ******************************************************************

; *** LCD_Init: Routine to initialize the LCD.

LCD_Init:  push  Temp

    ldi  DelayTime, 255

    ; Put the LCD in 8-bit mode.  Even though we want the display to

    ; operate in 4-bit mode, the only way to guarantee that our commands

    ; are aligned properly is to initialize in 8-bit.  (The user might have

    ; hit reset between nibbles of a dual 4-bit cycle.)

    ldi  Temp, 0b00110000

    out  LCD_PORT, Temp

    rcall  LCD_PulseE

    rcall  DELAY

    rcall  DELAY

    ; Now it's safe to go into 4-bit mode.

    ldi  Temp, 0b00100000

    out  LCD_PORT, Temp

    rcall  LCD_PulseE

    rcall   DELAY

    rcall  DELAY

    ; *** Send the 'FUNCTION SET' command

    ;       +------ Data:  0 = 4-bit; 1 = 8-bit

    ;       |+----- Lines: 0 = 1; 1 = 2

    ;       ||+---- Font:  0 = 5x8; 1 = 5x11

    ldi  Temp, 0b00101100

    rcall   LCD_SendCmd

    ; *** Send the 'CURSOR/DISPLAY SHIFT' command

    ;        +----- S/C:  0 = cursor; 1 = display

    ;        |+---- R/L:  0 = left; 1 = right

    ldi  Temp, 0b00010100

    rcall   LCD_SendCmd

    ; *** Send the 'DISPLAY ON/OFF' command

    ;         +---- Display: 0 = off; 1 = on

    ;         |+--- Cursor: 0 = off; 1 = on

    ;         ||+-- Blink: 0 = off; 1 = on

    ldi  Temp, 0b00001111

    rcall   LCD_SendCmd

    ; *** Send the 'ENTRY MODE' command

    ;          +--- Direction: 0 = left; 1 = right

    ;          |+-- Shift Dislay: 0 = off; 1 = on

    ldi  Temp, 0b00000110

    rcall   LCD_SendCmd

    rcall   LCD_Clear

    pop   Temp

    ret

; *** LCD_PrintMem: Prints from memory.

;       Put the starting memory location in Z (r31:r30)

;       Put the number of characters to print in Temp2

;  After execution, Z is at the character AFTER the last to be printed

;                   and Temp2 is zero.

;       This function will not wrap if you the string is bigger than the LCD.

LCD_PrintMem:  push  Temp

   LCD_MemRead: ld  Temp, Z+

    rcall  LCD_SendChar

    dec  Temp2

    brne  LCD_MemRead

    pop  Temp

    ret

; *** LCD_PrintPM: Prints from program memory

LCD_PrintPM:  push  r0

    push  Temp

    LCD_PMRead: lpm

        mov  Temp, r0

    rcall  LCD_SendChar

    adiw  r30, 1

    dec  Temp2

    brne  LCD_PMRead

    pop  Temp

    pop  r0

    ret

; *** LCD_Clear: Clears the display and sends the cursor home.

LCD_Clear:  push   Temp

    ; *** Clear the display

    ldi  Temp, 0b00000001

    rcall   LCD_SendCmd

    ; *** Send the cursor home

    ldi  Temp, 0b00000010

    rcall   LCD_SendCmd

    pop  Temp

    ret

; *** LCD_SendCmd: Routine to write a command to the instruction register.

;       The value to be written should be stored in Temp.

;       The value is sent 4 bits at a time.

LCD_SendCmd:  push   Temp

    push   Temp2

    rcall  LCD_WaitBusy

    mov   Temp2, Temp    ; Make a backup copy

    andi   Temp2, 0b11110000  ; Only use the upper nibble

    out  LCD_PORT, Temp2    ; Send it

    rcall   LCD_PulseE    ; Pulse the enable

    swap  Temp      ; Swap upper/lower nibble

    andi   Temp, 0b11110000  ; Only use the upper nibble

    out  LCD_PORT, Temp    ; Send it

    rcall   LCD_PulseE    ; Pulse the enable

    pop   Temp2

    pop   Temp

    ret

; *** LCD_SendChar: Routine to write a character to the data register.

;       The value to be written should be stored in Temp.

;       The value is sent 4 bits at a time.

LCD_SendChar:  push   Temp

    push   Temp2

    mov   Temp2, Temp    ; Make a backup copy

    rcall  LCD_WaitBusy

    mov   Temp, Temp2    ; Make a backup copy

    andi   Temp2, 0b11110000  ; Only use the upper nibble

    ori  Temp2,  0b00001000

    out  LCD_PORT, Temp2    ; Send it

    rcall   LCD_PulseE    ; Pulse the enable

    swap  Temp      ; Swap upper/lower nibble

    andi   Temp,  0b11110000  ; Only use the upper nibble

    ori  Temp,  0b00001000

    out  LCD_PORT, Temp    ; Send it

    rcall   LCD_PulseE    ; Pulse the enable

    pop   Temp2

    pop   Temp

    ret

; *** LCD_WaitBusy: Wait for the busy flag to go low.

;       Waits for the busy flag to go low.  Since we're in 4-bit mode,

;       the register has to be read twice (for a total of 8 bits).  The

;       second read is never used.

;       If you need more code space, this function could be replaced with

;       a simple delay.

LCD_WaitBusy:  push   Temp

    ldi  Temp, 0b00001111  ; Disable data bit outputs

    out  LCD_DDR, Temp

    ldi  Temp, 0x00    ; Clear all outputs

    out  LCD_PORT, Temp

LCDWaitLoop:  ldi  Temp, 0b00000100  ; Enable only read bit

    out  LCD_PORT, Temp

    sbi  LCD_PORT, LCD_E    ; Raise the Enable signal.

    nop

    nop

    in  Temp, LCD_PIN    ; Read the current values

    cbi  LCD_PORT, LCD_E    ; Disable the enable signal.

    rcall   LCD_PulseE    ; Pulse the enable (the second nibble is discarded)

    sbrc  Temp, 7      ; Check busy flag

    rjmp  LCDWaitLoop

    ldi  Temp, 0b11111111  ; Enable all outputs

    out  LCD_DDR, Temp

    pop  Temp

    ret

LCD_PulseE:  sbi  LCD_PORT, LCD_E

    nop

    nop

    cbi  LCD_PORT, LCD_E

    ret

; *** Provide millisecond delay (DelayTicks specifies number of ms)

DELAY:  push DelayTime

  push r25

  ldi  r25, DelayCount1

DELAY1:  dec r25

  brne DELAY1

  dec DelayTime

  brne DELAY1

  pop r25

  pop DelayTime

  ret

    ; Put the LCD in 8-bit mode.  Even though we want the display to

    ; operate in 4-bit mode, the only way to guarantee that our commands

    ; are aligned properly is to initialize in 8-bit.  (The user might have

    ; hit reset between nibbles of a dual 4-bit cycle.)

    ldi  Temp, 0b00110000

    out  LCD_PORT, Temp

    rcall  LCD_PulseE  ; x1

    rcall  DELAY

    rcall  LCD_PulseE  ; x2

    rcall  DELAY

    ; Now it's safe to go into 4-bit mode.

    ldi  Temp, 0b00100000

    out  LCD_PORT, Temp

    rcall  LCD_PulseE  ; x3

    rcall  DELAY