754



754            2F2            CH1
     Prior keyboard character code (most recently read and
     accepted). This is the previous value passed from 764 ($2FC). If
     the value of the new key code equals the value in CH1, then the
     code is accepted only if a suitable key debounce delay has taken
     place since the prior value was accepted.

755            2F3            CHACT
     Character Mode Register. Zero means normal inverse
     characters, one is blank inverse characters (inverse characters
     will be printed as blanks, i.e., invisible), two is normal
     characters, three is solid inverse characters. Four to seven is the
     same as zero to three, but prints the display upside down.
     This register also controls the transparency of the cursor. It is
     transparent with values two and six, opaque with values three
     and seven. The cursor is absent with values zero, one, four and
     five.

     Toggling BIT 0 on and off can be a handy way to produce a
     blinking effect for printed inverse characters (characters with
     ATASCII values greater than 128 -- those that have BIT 7 set).
     Shadow for 54273 ($D401). There is no visible cursor for the
     graphics mode output. CHACT is initialized to two.
     Here's an example of blinking text using this register:

     10 CHACT=755:REM USE INVERSE FOR WORD
        S BELOW
     15 PRINT "[THIS IS A TEST OF BLINKING ]
       [TEXT]"
     20 POKE CHACT,INT(RND(0)*4)
     30 FOR N=1 TO 100:NEXT N:GOTO 15

     See COMPUTE!, December 1981.
     Using a machine language routine and page six space, try:

     10 PAGE=1536:EXIT=1568
     20 FOR N=PAGE TO EXIT:READ BYTE:POKE
        N,BYTE:NEXT N
     30 PGM=USR(PAGE)
     40 PRINT "[THIS] IS A [TEST] OF [BLINKING]
        TEXT":REM MAKE SOME WORDS INVERSE
     50 GOTO 50
     60 DATA 104,169,17,141,40,2,169,6,141
        ,41
     70 DATA 2,169,30,141,26,2,98,173,243,
        2
     80 DATA 41,1,73,1,141,243,2,169,30,14
        1,26,2,96