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playground:playground [2022-03-11 22:43]
erhan removed
playground:playground [2022-03-11 22:46] (current)
erhan old revision restored (2015-10-03 14:50)
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-====== Scanning the keyboard without joysticks interfere ======+====== PlayGround ======
  
-Converts keycode ($00-$3F) to $DC00-$DC01 values and scans without interfering from joysticks at port 1 or 2. Also keeps history, to detect key press & hold. 
- 
-<code> 
- 
-;64tass format 
-;with default $dc02 - $dc03 values ($ff and $00) 
-;taken from Platoon game, shortened and key history integrated. 
-;code to key conversion table below, from c64-wiki.com 
- 
-;to use inside irq, below code is enough : 
-; lda #$keycode 
-; jsr keyscan 
-; bcc + 
-; inc $d020 
-;+ rts  
- 
-;$00 Inst/Del $10 5 $20 9 $30 £ 
-;$01 Return $11 R $21 I $31 * 
-;$02 Crsr ←→ $12 D $22 J $32 ] 
-;$03 F7/F8 $13 6 $23 0 $33 Clr/Home 
-;$04 F1/F2 $14 C $24 M $34 R.Shift 
-;$05 F3/F4 $15 F $25 K $35 = 
-;$06 F5/F6 $16 T $26 O $36 ↑ 
-;$07 Crsr ↑↓ $17 X $27 N $37 ? 
-;$08 3 $18 7 $28 + $38 1 
-;$09 W $19 Y $29 P $39 ← 
-;$0A A $1A G $2A L $3A Ctrl 
-;$0B 4 $1B 8 $2B − $3B 2 
-;$0C Z $1C B $2C > $3C Space 
-;$0D S $1D H $2D [ $3D Commodore 
-;$0E E $1E U $2E @ $3E Q 
-;$0F L.Shift $1F V $2F < $3F Run/Stop 
- 
- 
- * = $1000 
-  
- lda #$3e ;scan for key "Q" 
- jsr keyscan 
- bcc + 
- inc $d020 ;C=1, this code executed if key is pressed 
-+  
-- lda $d011 
- bpl - 
-- lda $d011 
- bmi - 
-  
- jmp $1000  
-  
-keyscan  
-; sty backy+1 ;remove comment if you need .Y preserved 
- pha 
- lsr 
- lsr 
- lsr 
- tay 
- lda row,y 
- sta $dc00 
- pla 
- and #$07 
- tay 
- lda $dc01 
- and column,y 
- bne nokey 
- lda #$ff ;key is checked 2nd time, to be sure of 
- sta $dc00 ;joy #1 and #2 are not interfering 
- lda $dc01 
- and column,y 
- beq nokey 
-  
- cmp histv ;history value ? 
- bne +  
- clc         ;case #3, key is held down. keep history & set C=0 
- bcc backy 
-  
-nokey asl ;case #1, no keypress, update history value 2x & set C=0 
- clc  
- .byte $24  
-+ sec ;case #2, key pressed&released. update history & set C=1 
- sta histv 
-  
-backy  
-; ldy #$00 ;remove comment if you need .Y preserved 
- lda #$ff 
- sta $dc00 ;set default value 
- lda #$7f 
- sta $dc01 ;set default value 
- rts 
- 
-  
-row .byte $fe,$fd,$fb,$f7,$ef,$df,$bf,$7f 
-column .byte $01,$02,$04,$08,$10,$20,$40,$80  
-histv .byte $00 
- 
-</code> 
playground/playground.txt · Last modified: 2022-03-11 22:46 by erhan