Subject:
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Machine code PRINT routine
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 6 Apr 1998 22:12:18 GMT
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Original-From:
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Charles Hacker EAS <C.HACKER@ihatespamSTE.GU.EDU.AU>
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Reply-To:
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c.hacker@easSTOPSPAMMERS.gu.edu.au
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Viewed:
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1164 times
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Hello All,
I have been able to get a machine code print routine to work.
The code that will print two lines to the LCD screen follows.
Fred Martin had requested I send the code to the HandyBoard list.
Note that No interrupts have been set up.
The Print screen routine is copied to Zero page with each
new character printed, (to account for interrupts etc trashing zero
page as well).
I had a few problems getting the display to work, and had to
obtain a manual for the display.
Some problems I discovered:
1. You need to Turn Display On first, (with an $0C code).
2. The display in One line is so dark, the words can not be seen.
The display thus needs to be operated in two line display.
3. The screen buffer is bigger than the display. Hence you need to
write multiple characters to the end of line one, to get to line
two.
__________________________________________
* HC11 - Equates
*
PORTA EQU $00 ; Port A data register
PORTB EQU $04 ; Port B data register
PORTC EQU $03 ; Port C latched data register
PORTD EQU $08 ; Port D data register
PORTE EQU $0A ; Port E data register
DDRC EQU $07 ; Data Direction register for port C
HPRIO EQU $3C ; Highest Priority Interrupt and misc.
*
* Display Equates
*
LCDtmpA
EQU $0009
LCDrout
EQU $0010
*
ORG $BFFE
FDB $8000 ;org to the reset vector
*
* Start of Prog
*
ORG $8000
LDS #$E000
*
* Do Print to screen
*
JSR CPYprt
LDAA #$00
LDAB #$0C ; Display On / Cursor Off / Flash Off
JSR LCDrout
*
JSR CPYprt
LDAA #$00
LDAB #$38 ; Two Display
JSR LCDrout
*
JSR CPYprt
LDAA #$00
LDAB #$03 ; Home and Clear Display
JSR LCDrout
*
LDX #Line1 ; Tell to Print Line 1
STX SCRend
PL1 JSR CPYprt
LDAA #$02
LDX SCRend
LDAB $00,X
INX
STX SCRend
JSR LCDrout
LDX SCRend
CPX #Line2
BNE PL1
*
LDAA #24 ; Move to Next Line
NewL STAA SCRend
JSR CPYprt
LDAA #$02
LDAB #40
JSR LCDrout
LDAA SCRend
DECA
BNE NewL
*
LDX #Line2 ; Tell to Print Line 2
STX SCRend
PL2 JSR CPYprt
LDAA #$02
LDX SCRend
LDAB $00,X
INX
STX SCRend
JSR LCDrout
LDX SCRend
CPX #Lend
BNE Pl2
*
AGAIN LDAA #$FA
STAA $7000
*
LDX #$8000 ; Delay for count
LOP1 DEX
BNE LOP1
*
LDAA #$F5
STAA $7000
*
LDX #$8000 ; Delay for count
LOP2 DEX
BNE LOP2
*
JMP AGAIN
*
Line1 FCC 'Print Line 1 !!!'
Line2 FCC 'This is Line 2 !'
Lend FCB $00
*
*
* Copy print routine to Zero Page
*
CPYprt LDX #SCRbeg
LDY #LCDrout
LCDloop
LDAA 0,X
STAA 0,Y
INX
INY
CPX #SCRend
BNE LCDloop
RTS
*
* Print Routine: A - Command, B - Data
* Copied to Zero Page memory and Run there
*
SCRbeg SEI ; disable interrupts
LDX #$1000
BCLR HPRIO,X %00100000 ; put into single chip mode
BCLR PORTA,X %00010000 ; turn off LCD E line
STAA LCDtmpA ; Temp A store
CLR DDRC,X ; make port C input
LCDBsy LDAA #1
STAA PORTB,X ; read operation from LCD (AKF-added ',X')
BSET PORTA,X %00010000 ; frob LCD on
LDAA PORTC,X ; get status
BCLR PORTA,X %00010000 ; frob LCD off
ANDA #$80 ; bit 7 is busy flag
BNE LCDBsy
LDAA #$FF
STAA DDRC,X ; make port C output
LDAA LCDtmpA ; Temp A store
STAA PORTB,X ; high byte is control
STAB PORTC,X ; low byte is data
BSET PORTA,X %00010000
BCLR PORTA,X %00010000 ; frob LCD
BSET HPRIO,X %00100000 ; put into expanded chip mode
CLI ; enable interrupts
RTS ; return to monitor command loop
SCRend RMB 2
Charles Hacker
School of Engineering
Griffith University - Gold Coast
PMB 50 Gold Coast Mail Centre
Southport Queensland 9726
Australia.
Email - C.Hacker@eas.gu.edu.au
Ph. (07) 55948 670
Fax.(07) 55948 065
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