Program for initialize two row lcd, Assembly Language

Assignment Help:

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


Related Discussions:- Program for initialize two row lcd

Assignment, You have to write a subroutine (assembly language code using NA...

You have to write a subroutine (assembly language code using NASM) for the following equation. Dx= ax2+(ax-1)+2*(ax+2)/2

Hand shaking-microprocessor, Hand shaking : Handshaking, or 2-way hand...

Hand shaking : Handshaking, or 2-way handshaking, is 1 type of strobe operation. It typically involves 2 handshaking lines: an output line to denote when the board is ready an

Shell script, write shell to calculate basic salary from given .

write shell to calculate basic salary from given .

8088 timing system diagram-Microprocessor, 8088  Timing System Diagram ...

8088  Timing System Diagram The 8088 address/data  bus is divided  in 3 parts (a) the lower 8 address/data  bits, (b) the middle 8 address bits, and (c) the upper 4 status/

Overview of intel pro-pentium, Overview of Intel Pro-Pentium : The 2 c...

Overview of Intel Pro-Pentium : The 2 chief players in the PC CPU market are Motorola and Intel.  Intel has enjoyed incredible success with its processors since the early 1980

Hold response sequence-microprocesssor, Hold Response Sequence The HOLD...

Hold Response Sequence The HOLD pin is examined at leading edge of each clock pulse. If it is received active line by the processor before T4 of the earlier cycle/during the T1

Program for initialize two row lcd, init_lcd                        ;(this ...

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

Test-logical instruction-microprocessor, TEST : Logical Compare Instructio...

TEST : Logical Compare Instruction: The TEST instruction performs bit by bit logical AND operation on the 2 operands. Each bit of the result is then set to value I, if the equival

ADDITION-SUBTRACTION, HELLO I AM TRYING TO ADD AND SUBTRACT BUT I SEEM CAN'...

HELLO I AM TRYING TO ADD AND SUBTRACT BUT I SEEM CAN''T FIND THE CORRECT REGISTER TO PUT IN

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd