Character map select   index 03h  SEQU

Layout  b5     SAH  Select character generator A (high)
        b4     SBH  Select character generator B (high)
        b3,b2  SA   Select character generator A
        b1,b0  SB   Select character generator B

- Character map select
        Either one or two character sets can be active at one time.

        bits 543210        Char. map   Offset
             000000 = 00h  0            0 kb
             000101 = 05h  1           16 kb
             001010 = 0Ah  2           32 kb
             001111 = 0Fh  3           48 kb
             110000 = 30h  4            8 kb
             110101 = 35h  5           24 kb
             111010 = 3Ah  6           40 kb
             111111 = 3Fh  7           56 kb


        Note
        It is recommended to set the Color plane enable register
        if two fonts are active.