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@ -5,6 +5,22 @@ |
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; |
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;====================================================================== |
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; |
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; NABU KEYBOARD CODES: |
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; |
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; $00-$7F STANDARD ASCII CODES |
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; $80-$8F JOYSTICK PREFIXES ($80 = JS1, $81 = JS2) |
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; $90-$9F KEYBOARD ERROR CODES |
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; $A0-$BF JOYSTICK DATA |
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; $C0-$DF UNUSED |
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; $E0-$EF SPECIAL KEYS |
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; |
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; NOTE THAT THE ERROR CODE $94 IS A WATCHDOG TIMER THAT WILL BE |
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; SENT BY THE KEYBOARD EVERY 3.7 SECONDS. |
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; |
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; THE CODE BELOW WILL IGNORE (SWALLOW) THE ERROR CODES ($90-$9F) AND |
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; WILL TRANSLATE SPECIAL KEYS ($E0-$FF) TO ROMWBW EQUIVALENTS. ALL |
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; OTHER KEYS WILL BE PASSED THROUGH AS IS. |
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; |
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; KBPORT EQU $90 |
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; |
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; POLL FOR INPUT |
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@ -58,18 +74,28 @@ NABUKB_STAT: |
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RET NZ ; KEY WAITING, ALL SET |
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IN A,(NABUKB_DAT+1) ; GET BKD STATUS |
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AND $02 ; CHECK DATA RDY BIT |
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JR Z,NABUKB_STAT1 ; BAIL OUT IF NOT |
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JR Z,NABUKB_STATX ; BAIL OUT IF NOT |
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IN A,(NABUKB_DAT) ; GET THE KEY |
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BIT 7,A ; HIGH BIT IS SPECIAL CHAR |
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CALL NZ,NABUKB_XLAT ; IF SO, TRANSLATE IT |
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JR C,NABUKB_STAT1 ; CF INDICATES INVALID |
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JR Z,NABUKB_STAT2 ; IF NORMAL CHAR, BUFFER IT |
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CP $90 ; START OF ERR CODES |
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JR C,NABUKB_STAT1 ; NOT ERR CODE, CONTINUE |
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CP $A0 ; END OF ERR CODES |
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JR NC,NABUKB_STAT1 ; NOT ERR CODE, CONTINUE |
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JR NABUKB_STATX ; IS ERR CODE, IGNORE IT |
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NABUKB_STAT1: |
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CP $E0 ; SPECIAL CHARACTER? |
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JR C,NABUKB_STAT2 ; IF NOT, SKIP XLAT, BUFFER KEY |
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CALL NABUKB_XLAT ; IF SO, TRANSLATE IT |
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JR C,NABUKB_STATX ; CF INDICATES INVALID |
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NABUKB_STAT2: |
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LD (NABUKB_KEY),A ; BUFFER IT |
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LD A,1 ; KEY WAITING STATUS |
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LD A,1 ; SIGNAL KEY WAITING |
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LD (NABUKB_KSTAT),A ; SAVE IT |
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OR A ; SET FLAGS |
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RET |
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RET ; DONE |
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; |
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NABUKB_STAT1: |
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NABUKB_STATX: |
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XOR A ; SIGNAL NO CHAR READY |
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JP CIO_IDLE ; RETURN VIA IDLE PROCESSOR |
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; |
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Wayne Warthen
2 years ago