Program for initialize two row lcd, Assembly Language

init_lcd                        ;(this initialises a 2 row lcd)

    bcf     TRISA,0             ;PORTA bit 0 as an output (lcd RS pin)
    bcf     TRISA,1             ;PORTA bit 1 as an output (lcd R/W pin)
    bcf     TRISA,2             ;PORTA bit 2 as an output (lcd E pin)

    
    bcf     lcd_rs
    bcf     lcd_rw
    bcf     lcd_en
    movlw   b'00110000'         ;Instruction - function set. First of 3
    call    lcd_write
    call    Delay5              ;wait MORE THAN 4.1mS


    movlw   b'00110000'         ;Instruction - function set. Second of 3
    call    lcd_write
    movlw   .33                 ;wait MORE THAN 100uS [(33 x 3) +1 +1 + (1 x 2)] - measured 102uS on scope
    movwf   counta              ;1 cycle
    decfsz  counta              ;1 cycle until true then a 2 cycle
    goto    $-2                 ;2 cycle instruction

    movlw   b'00110000'         ;Instruction - function set. Third of 3
    call    lcd_write

    movlw   b'00111000'         ;8 bit data / 2 line display / 5x8 character font
    call    lcd_write
    call    busy

    movlw   b'00001111'         ;instruction bit / display on / cursor position on / blinking cursor on
    call    lcd_write
    call    busy

    movlw   b'00000001'
    call    lcd_write
    call    busy

    movlw   b'00000110'         ;increment cursor position by 1 / don't shift display
    call    lcd_write
    call    busy

    return  ;return from initialization routine

lcd_write

    movwf   lcd_data            ;data to port
    bsf     lcd_en              ;sets LCD enable pin high
    bcf     lcd_en              ;data is latched into lcd on high to low transition of E

    return

busy

    bsf     TRISC,7             ;was output when sending init data, now input to read busy flag
    bsf     lcd_rw              ;set high to read data from lcd
    bsf     lcd_en              ;enable
    btfsc   lcd_busy            ;is the busy flag low?
    goto    $-2                 ;no, go back and keep checking until it is
    bcf     lcd_en              ;busy flag now clear
    bcf     lcd_rw              ;set lcd back to write mode
    bcf     TRISC,7             ;port bit as an output again

    return
Delay30
        movlw   .30             ;delay 30mS
        goto    d0
Delay5
        movlw   .5              ;delay 5ms
d0      movwf   count1
d1      movlw   0xC7
        movwf   counta
        movlw   0x01
        movwf   countb
Delay_0
        decfsz  counta
        goto    $+6
        decfsz  countb
        goto    Delay_0
        decfsz  count1
        goto    d1

        retlw   .0              ;return from the delay routine

Posted Date: 3/5/2013 4:26:44 AM | Location : United States







Related Discussions:- Program for initialize two row lcd, Assignment Help, Ask Question on Program for initialize two row lcd, Get Answer, Expert's Help, Program for initialize two row lcd Discussions

Write discussion on Program for initialize two row lcd
Your posts are moderated
Related Questions
Write a program on the assembly language to do the following: 1- Allocate array with 32bit 100 element 2- Prompt the user to enter the maximum or the upper bound of the rando

Program: Write a program to perform addition of a series of 8-bit numbers. The series have 100 (numbers). Solution : In the first program, we have been implemented the add

Flowchart for the sequence of 8251 Whether the control, mode or sync character register is selected depends on the accessing sequence.  A flowchart of the sequencing is given i

IMUL: Signed Multiplication: This instruction multiplies a signed byte by a signed bit in source operand e in the register AL or signed word in source operand by signed word in th

Entering a Program In this section, we will explain the procedure for entering a small program on IBM PC with DOS operating system. Assume a program of addition of 2 bytes, as

DMA DMA stands for Direct Memory Access It is uses same Address/Data lines on ISA bus It controls the ISA bus instead of the processor ("bus master") Floppy

Internal Hardware-Interrupts Internal hardware-interrupts are the outcome of sure situations that occur during the execution of a program, for example. Divide by 0. The interru

Why is the capability to relocate processes desirable?

Write a nonrecursive version of the Factorial procedure (Section 8.3.2) that uses a loop. (A VideoNote for this exercise is posted on the Web site.) Write a short program that inte

Trying to convert small programs from C to 8086 assembly language using emu 8086 emulator. I converted to low level C, but struggling with converting to the Assembly language.