*** ASSEMBLY SUCCESSFUL ***
0010 AGAIN 009B ALLPSIN 0063 BFCHECK 0072 CHECK_AGAIN
0092 COMBEGADR 000A COMMAND 004D COMMON 0003 CWADR
000B DATA 0096 DATABEGADR 0086 DELAY 000E DISABLE
000F ENABLE 002E NEXTCOM 0039 NEXTDATA 0004 NUMOFC
0010 NUMOFD 0000 PAADR 0082 PACOUTBIN 0090 PAINCOUT
0080 PANDCOUT 0001 PBADR 0002 PCADR 0089 PDELAY
000D READ 0040 SENDCHAR 0041 SENDCHARA 0048 SENDCOM
0049 SENDCOMA 000C WRITE
;********************************************************************
;====================================================================
; Program:Hello World
; programmers: Dincer Aydin & Caner Buyuktuna
; function:Displays "Hello World !!!!" on the LCD Screen
;====================================================================
;********************************************************************
; This code requires a 2*16 LCD connected to a 8255 with base address of 00h
; routines sendcomA & sendcom & sendcharA & sendchar have been tested on
; >> 2*16 Hitachi LCD with HD44780 chip
; >> Samsung 1*16 LCD with a KS0062F00 chip
; >> 2*16 Epson LCD marked P300020400 SANTIS 1 ,and
; >> noname 1*16 HD44780 based LCD.
; The Z80 was clocked at 2 MHz and 4,9152 MHz for each display.This was done
; because the routines mentioned above take many t states and in most cases
; that will be longer that the time a HD44780 will need to execute a command.
;
; Connections:
; LCD data bus(pins #14-#7) connected to Port A of a 8255 with 00h base address
; LCD Enable pin(#6) connected to Port C bit #7
; LCD R/W pin(#5) connected to Port C bit #6
; LCD RS pin(#4) connected to Port C bit #5
;8255 port address(base 00h):
0000 PAADR EQU 00H ; Address of PortA
0000 PBADR EQU 01H ; Address of PortB
0000 PCADR EQU 02H ; Address of PortC
0000 CWADR EQU 03H ; Address of Control Word
;stuff to be written into the control word of the 8255:
;Some of the change the state of the ports and some manipulate
;bits on port C
0000 ALLPSIN EQU 9BH ; set all ports to input mode
0000 PAINCOUT EQU 90H ;A input,C output,B output
0000 PANDCOUT EQU 80H ;set all ports to output mode
0000 PACOUTBIN EQU 82H ;A output,C output,B input
;bit set/reset commands.These bits are the control signals for the LCD
0000 ENABLE EQU 0FH ; set portC bit #6
0000 DISABLE EQU 0EH ; reset portC bit #6
0000 READ EQU 0DH ; set portC bit #5
0000 WRITE EQU 0CH ; reset portC bit #5
0000 COMMAND EQU 0AH ; reset portC bit #4
0000 DATA EQU 0BH ; set portC bit #4
; Define number of commands and length of string data
0000 NUMOFC EQU 4H ; number of commands
0000 NUMOFD EQU 10H ; number of string bytes
; initialization:
0000 31 00 02 LD SP,200H ; Set stack pointer
0003 0E 03 LD C,CWADR
0005 3E 82 LD A,PACOUTBIN ; Ports A&C output,B input
0007 ED 79 OUT (C),A
; *********It all begins here**********:
; This part sends commands to initialize the LCD
0009 CD 86 00 CALL DELAY
000C 3E 38 LD A,38H ; function set command
000E 06 04 LD B,4
0010 0E 03 AGAIN: LD C,CWADR
0012 16 0A LD D,COMMAND
0014 ED 51 OUT (C),D ; select the instruction register
0016 16 0C LD D,WRITE
0018 ED 51 OUT (C),D ; reset RW pin for writing to LCD
001A D3 00 OUT (PAADR),A ; place the command into portA
001C 16 0F LD D,ENABLE
001E ED 51 OUT (C),D ; enable the LCD
0020 16 0E LD D,DISABLE
0022 ED 51 OUT (C),D ; disable the LCD
0024 CD 86 00 CALL DELAY ; wait for a while
0027 10 E7 DJNZ AGAIN ; loop till the command is sent 4 times
; send commands to set input mode, cursor,number of lines ,and etc.
0029 21 92 00 LD HL,COMBEGADR ; set HL to point the first command
002C 06 04 LD B,NUMOFC ; put the number of commands to be sent in B
002E CD 48 00 NEXTCOM: CALL SENDCOM ; send (HL) as a command
0031 23 INC HL ; point the next command
0032 10 FA DJNZ NEXTCOM ; loop till all commands are sent
; This part sends strings to the LCD:
0034 21 96 00 LD HL,DATABEGADR ; set HL to point the first string byte
0037 06 10 LD B,NUMOFD ; put the number of string bytes to be sent in B
0039 CD 40 00 NEXTDATA: CALL SENDCHAR ; send (HL) as string data
003C 23 INC HL ; point the next string byte
003D 10 FA DJNZ NEXTDATA ; loop till all string bytes are sent
003F 76 HALT
; ====================================================================
; Subroutine name:sendcomA & sendcom & sendcharA & sendchar
; programmer:Caner Buyuktuna & Dincer Aydin
; input:A or (HL)
; output:
; Registers altered:A
; function: sendcharA sends the data in A to the LCD
; sendchar sends the data in (HL) to the LCD
; sendcomA sends the command in A to the LCD
; sendcom sends the command in (HL) to the LCD
; ====================================================================
0040 7E SENDCHAR: LD A,(HL) ; put the data to be sent to the LCD in A
0041 C5 SENDCHARA: PUSH BC ; save BC
0042 D5 PUSH DE ; save DE
0043 1E 0B LD E,DATA ;
0045 C3 4D 00 JP COMMON
0048 7E SENDCOM: LD A,(HL)
0049 C5 SENDCOMA: PUSH BC ; save BC
004A D5 PUSH DE ; save DE
004B 1E 0A LD E,COMMAND
004D CD 63 00 COMMON: CALL BFCHECK ; See if the LCD is busy. If it is busy wait,till it is not.
0050 ED 59 OUT (C),E ; Set/reset RS accoring to the content of register E
0052 16 0C LD D,WRITE
0054 ED 51 OUT (C),D ; reset RW pin for writing to LCD
0056 D3 00 OUT (PAADR),A ; place data/instrucrtion to be written into portA
0058 16 0F LD D,ENABLE
005A ED 51 OUT (C),D ; enable the LCD
005C 16 0E LD D,DISABLE
005E ED 51 OUT (C),D ; disable the LCD
0060 D1 POP DE ; restore DE
0061 C1 POP BC ; restore BC
0062 C9 RET ; return
; ====================================================================
; Subroutine name:bfcheck
; programmer:Dincer Aydin
; input:
; output:
; Registers altered:D
; function:Checks if the LCD is busy and waits until it is not busy
; ====================================================================
0063 F5 BFCHECK: PUSH AF ; save AF
0064 0E 03 LD C,CWADR
0066 16 90 LD D,PAINCOUT
0068 ED 51 OUT (C),D ; make A input,C output,B output
006A 16 0D LD D,READ
006C ED 51 OUT (C),D ; set RW pin for reading from LCD
006E 16 0A LD D,COMMAND
0070 ED 51 OUT (C),D ; select the żnstruction register
0072 16 0F CHECK_AGAIN: LD D,ENABLE
0074 ED 51 OUT (C),D ; enable the LCD
0076 DB 00 IN A,(PAADR) ; read from LCD
0078 16 0E LD D,DISABLE
007A ED 51 OUT (C),D ; disable the LCD
007C 07 RLCA ; rotate A left through C flag to see if the busy flag is set
007D DA 72 00 JP C,CHECK_AGAIN ; if busy check it again,else continue
0080 16 80 LD D,PANDCOUT
0082 ED 51 OUT (C),D ; set all ports to output mode
0084 F1 POP AF ; restore AF
0085 C9 RET
;====================================================================
; Subroutine name:DELAY and PDELAY
; programmer(s):Dincer Aydin
; input:the value in HL (for PDELAY only)
; output:-
; Registers altered:H,L
; function:delay
; for more delay you can add a few nops or or some junk commands using the index
; registers
; pdelay uses what you put into HL before you called the PDELAY routine
;====================================================================
0086 21 10 10 DELAY: LD HL,1010H
0089 2D PDELAY: DEC L
008A C2 89 00 JP NZ,PDELAY
008D 25 DEC H
008E C2 89 00 JP NZ,PDELAY
0091 C9 RET
;====================================================================
; commands and strings
0092 01 80 0C 06 COMBEGADR: DB 01H,80H,0CH,06H
; clear display,set DD RAM adress,
; turn on display with cursor hidden,set entry mode
; Hello World !!!!
0096 48 65 6C 6C DATABEGADR: DB 48H,65H,6CH,6CH
009A 6F 20 57 6F DB 6FH,20H,57H,6FH
009E 72 6C 64 20 DB 72H,6CH,64H,20H
00A2 21 21 21 21 DB 21H,21H,21H,21H
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