CX85 Keypad Interrrupt Handler#

original Atari source from the CX-85 Disk

<verbatim> ;DEMONSTRATION OF CX-85 KEYPAD INTERRUPT HANDLER ;FLORA P. NG 3/08/82 ; ;This keypad interrupt handler detects and handles all ;keys pressed on a CX-85 keypad plugged into port 2. ;This is assembled using Atari Macro Assembler. ; TIMER EQU $30 TIMER1 EQU 6 START EQU $9 ;START MASK SELECT EQU $A ;SELECT MASK OPTION EQU $C ;OPTION MASK BPOT EQU $08 ;BPOT BIT MASK VVBLKD EQU $224 ;VERTICAL BLANK INTERRUPT STRIG1 EQU $285 ;TRIGGER 1 ATTRACT EQU $4D ;ATTRACT MODE FLAG CH EQU $2FC ;KEYBOARD CODE ALLPOT EQU $D208 ;ALL POT STATUS PORTA EQU $D300 ;PORTA SETVBV EQU $E45C ;ROUTINE FOR SETTING VECTORS DOSINI EQU $0C ;WARM START ADDR CONSOL EQU $D01F ;CONSOL SWITCH PORT BREAK EQU $11 ;BREAK KEY FLAG ;LOCATED IN PAGE 6 BUT MAY BE REASSEMBLED ELSEWHERE ; ;INITIAL ENTRY POINT TO ESTABLISH VBLANK ENTRY ;SYSTEM RESET KEY RESETS VBLANK VECTORS, ;HENCE CHAIN TO DOS INIT ;SAVE VALUE IN DOSINI ORG $600 COLDST: LDA DOSINI STA WRMEXT+1 LDA DOSINI+1 STA WRMEXT+2 ;REPLACE DOSINI WITH WARMST LDA #LOW WARMST STA DOSINI LDA #HIGH WARMST STA DOSINI+1 ;CHAIN KEYPAD INTO DEFERRED VBLANK PROCESSING ;SAVE VVBLKD FOR KEYPAD EXIT POINT KPADVBI: LDA VVBLKD STA EXIT+1 LDA VVBLKD+1 STA EXIT+2 ; ;REPLACE VVBLKD WITH KEYPAD ENTRY POINT LDY #LOW KPAD LDX #HIGH KPAD LDA #7 ;DEFERRED VBI JSR SETVBV RTS ; ;ENTERED WHEN USER HITS SYSTEM RESET ;REESTABLISH VBLANK VECTOR WARMST: JSR KPADVBI WRMEXT: JMP 0 ;CHAIN TO DOSINI ; ; ;KEYPAD TRANSLATION TABLE ; KPADTAB: DB $0C,$0C ;FUNCTION 1 DB $14,$34 ;FUNCTION 2 DB $10,$07 ;FUNCTION 3 DB $18,$26 ;FUNCTION 4 DB $1C,$32 ;0 DB $19,$1F ;1 DB $1A,$1E ;2 DB $1B,$1A ;3 DB $11,$18 ;4 DB $12,$1D ;5 DB $13,$1B ;6 DB $15,$33 ;7 DB $16,$35 ;8 DB $17,$30 ;9 DB $1D,$22 ;. DB $1F,$0E ;- DB $1E,$06 ;+ENTER DB 0 ;END OF TABLE ;ENTERED AT EACH VBLANK TO READ THE KEYPAD KPAD: LDA STRIG1 ;KEY PRESSED? BNE KPADDM ;EXIT FOR KEY NOT PRESSED LDA #0 ;RESET ATTRACT MODE STA ATTRACT ;DETERMINE VALUE OF KEY PRESSED LDA PORTA ;READ CABLE PIN OF PORT 2 LSR A LSR A LSR A LSR A STA TEMP LDA ALLPOT ;READ ALLPOT FOR 5TH CABLE PIN STATUS AND #BPOT ;MASK FOR 5TH PIN EOR #BPOT ;COMPLEMENT BIT (O IS VALID) ASL A ORA TEMP ;A HAS KEY VALUE LDY #0 ;INIT COUNTER ; ;SCAN TRANSLATION TABLE KPADCK: CMP KPADTAB,Y ;MATCH KEYPAD TABLE ENTRY? BEQ KPADMAT ;JUMP IF MATCH INY ;INC TO NEXT ENTRY INY LDX KPADTAB,Y ;END OF TABLE? BEQ EXIT ;EXIT FOR END OF TABLE BNE KPADCK ; ;KEY VALUE MATCHES ;PUT NEW KEYCODE IN CH AND RESET AUTO-REPEAT KPADMAT: TAX ;SAVE KEY VALUE INY ;GET POKEY KEYCODE LDA KPADTAB,Y ;A HAS KEYCODE CMP #$FF ;VECTOR ROUTINE? BEQ KPADFUN ;EXIT FOR VECTOR ROUTINE CMP KPADCOD ;SAME AS PRIOR KEYCODE? BEQ KPADSAM ;BRANCH IF SAME STA KPADCOD ;ELSE STORE NEW KEYCODE STA CH LDA #TIMER ;RESET TIMER STA KPADREP BNE EXIT1 ; KPADDM: LDA #$C0 ;LOAD DUMMY VARIABLE STA KPADCOD EXIT1: ************************************* LDA #1 ;RESET BRK PRESS FLAG STA BRKPRS ************************************* BNE EXIT ;SAME AS PRIOR KEY, CHECK AUTO-REPEAT KPADSAM: LDX KPADREP ;AUTO-REPEAT EXPIRED? DEX ;DEC TIMER BNE KPADXX ;BRANCH IF NOT STA CH ;STORE KEYCODE LDA #TIMER1 ;RESET TIMER STA KPADREP BNE EXIT1 KPADXX: STX KPADREP ; ;EXIT THIS VBLANK INTERRUPT EXIT: JMP 0 ;CHAIN TO DEFERRED VBLANK TEMP: DB 0 ;TEMP VARIABLE KPADCOD: DB 0 ;PRIOR KEYCODE KPADREP: DB $30 ;AUTO-REPEAT TIMER ; ;IF NO $FF IN TRANSLATION TABLE, THE SeCTIONS ;ENCLOSED WITHIN *** MAY BE DELETED ************************************* BRKPRS: DB 1 ;BREAK PRESS FLAG ; ;FUNCTION VECTOR TABLE KPADFTB: DW KPADF1 ;F1 VECTOR DW KPADF2 ;F2 VECTOR DW KPADF3 ;F3 VECTOR DW KPADF4 ;F4 VECTOR ;GET FUNCTION VECTOR KPADFUN: DEY LDA KPADFTB,Y STA KPADFV+1 INY LDA KPADFTB,Y STA KPADFV+2 ;CALL TO FUNCTION VECTOR KPADFV: JSR 0 ;CALL TO FUNCTION JMP EXIT KPADF1: LDA BRKPRS BEQ KPADFR LDA #0 ;BREAK PRESSED STA BREAK STA BRKPRS LDA #$C0 ;LOAD DUMMY KEYCODE STA KPADCOD KPADFR: RTS KPADF2: LDA #OPTION STA CONSOL RTS KPADF3: LDA #SELECT STA CONSOL RTS KPADF4: LDA #START STA CONSOL RTS ************************************** END COLDST </verbatim>