например подключен LCD к порту B 0,1,2,3 PIC16F84A, а нужно подключить к B 4,5,6,7.
Не могу понять как определяются биты порта к которым подключен дисплей
С восьми битным интерфейсом всё понятно, использовать весь порт и всё.
Спойлер
;;;;;;;;;;Проба работы в 4 битном режиме;;;;;;;;;;;;;; LCD: D0-D7 подключены к RB0-RB7
; E - RA3, RS - RA2, R/W - GND
;==========
LIST P=16F84A
__CONFIG _XT_OSC & _CP_OFF & _PWRTE_OFF & _WDT_OFF
include P16F84A.inc
;==========
Var_1 equ 20h ;
Var_2 equ 21h ;
;==========
#define RS PORTA,2 ; вывод RS
#define E PORTA,3 ; вывод E
#define LCD_PORT PORTB
org 0 ;
;==========
clrf STATUS ; Настройка выводов МК
clrf PORTA ;
clrf PORTB ;
bsf STATUS,RP0 ;
clrf TRISA ;
clrf TRISB ;
bcf STATUS,RP0 ;
;===
; Variable Definitions
cblock H'20'
delay_1
delay_2
delay_3
tempLCD
endc
;==============
; Reset Vector
;org 0x0000
goto Start
Init
;===
; Set up port and pins
banksel TRISB ; select TRISC bus
movlw B'00000000' ; all pins output
movwf TRISB
banksel PORTB ; select LATC and clear
clrf PORTB
return
;========
; Delay subroutine which lasts for 100 * cty
delay_long
movwf delay_3
delay_long_loop2
movlw D'13'
movwf delay_2
clrf delay_1
delay_long_loop1
decfsz delay_1,f
goto delay_long_loop1
decfsz delay_2,f
goto delay_long_loop1
decfsz delay_3,f
goto delay_long_loop2
return
;==========
; Delay subroutine 1000 * cty
delay_short
movwf delay_2
delay_short_loop2
movlw D'249'
movwf delay_1
delay_short_loop1
nop
decfsz delay_1,f
goto delay_short_loop1
decfsz delay_2,f
goto delay_short_loop2
return
;==================
;LCD Initialisation
LCD_Init
movlw D'5'
call delay_long
;banksel PORTB
bcf RS ; commands so RS bit set low
movlw b'00010000' ; must be more than 15ms
call delay_short
;banksel PORTB
movlw 0x03 ; send first high nibble
movwf LCD_PORT
call Nibble
movlw D'6' ; must be more than 4.1ms
call delay_short
;banksel PORTB
movlw 0x03 ; send second high nibble
movwf LCD_PORT
call Nibble
movlw D'1' ; must be more than 100us
call delay_short
;banksel PORTB
movlw 0x03 ; send third high nibble
movwf LCD_PORT
call Nibble
movlw D'5' ; must be more than 5ms
call delay_short
;banksel PORTB
movlw 0x02 ; set 4 bit mode
movwf LCD_PORT
call Nibble
movlw 0x28 ; function set: 4 bit, 2 lines, 5 x 7 font
call LCD_Cmd
movlw 0x08 ; display switch: D = 0, C = 0, B = 0
call LCD_Cmd
call LCD_Clear
movlw 0x0C ; display switch: D = 1, C = 0, B = 0
call LCD_Cmd
movlw 0x06 ; input set: I/D = 1, S = 0
call LCD_Cmd
;banksel PORTB ; make sure LATC port is clear
clrf PORTB
movlw D'50' ; initialisation delay
call delay_long
return
;============
; LCD Command
LCD_Cmd
movwf tempLCD ; move contents of w into tempLCD
swapf tempLCD,w ; swap contents of tempLCD put result in w
andlw 0x0f ; select high nibble
movwf LCD_PORT
bcf RS ; RS set low due to instruction write
call Nibble
movlw D'1'
call delay_short
movfw tempLCD ; move contents of tempLCD into w
andlw 0x0f ; select low nibble
movwf LCD_PORT
bcf RS ; RS set low due to instruction write
call Nibble
movlw D'1'
call delay_short
return
;==========
; LCD Write
LCD_Write
movwf tempLCD ; move contents of w into tempLCD
swapf tempLCD,w ; поменять местами содержимое tempLCD положить результат в w
andlw 0xf ; Выбрать старший полубайт
movwf LCD_PORT ; Записать в порт
bsf RS ; RS set high due to instruction write
call Nibble
movlw D'1'
call delay_short
movfw tempLCD ; move contents of tempLCD into w
andlw 0xf ; select low nibble
movwf LCD_PORT
bsf RS ; RS set high due to instruction write
call Nibble
movlw D'5' ; vary this delay to control writing speed
call delay_long
return
;=========
; Send nibble - toggle E pin
Nibble
bsf E ; E set high
movlw D'1'
call delay_short
bcf E ; E set low
movlw D'2'
call delay_short
return
;===========
; LCD line 1
LCD_Line1
movlw 0x80
call LCD_Cmd
return
;===========
; LCD line 2
LCD_Line2
movlw 0xC0
call LCD_Cmd
return
;==============
; Clear Command
LCD_Clear
movlw 0x01
call LCD_Cmd
return
;============
; Write Space
LCD_Space
movlw 0x20
call LCD_Write
return
;=============
; Program main
Start
call Init
call LCD_Init
Main
call LCD_Clear
call LCD_Line1
Top_Line
movlw b'01001000' ; H
call LCD_Write
movlw 'e'
call LCD_Write
movlw 'l'
call LCD_Write
movlw 'l'
call LCD_Write
movlw 'o'
call LCD_Write
call LCD_Space
movlw 'W'
call LCD_Write
movlw 'o'
call LCD_Write
movlw 'r'
call LCD_Write
movlw 'l'
call LCD_Write
movlw 'd'
call LCD_Write
movlw D'255'
call delay_long
Bottom_Line
call LCD_Line2
movlw 'L'
call LCD_Write
movlw 'C'
call LCD_Write
movlw 'D'
call LCD_Write
movlw ' '
call LCD_Write
call LCD_Space
movlw 'p'
call LCD_Write
movlw 'i'
call LCD_Write
movlw 'c'
call LCD_Write
movlw '1'
call LCD_Write
movlw '6'
call LCD_Write
movlw 'f'
call LCD_Write
movlw D'255'
call delay_long
goto $ ; loop forever
end
