$01/1:   6510 On-chip 8-bit Input/Output Register

   +----------+---------------------------------------------------+
   | Bits 7-6 |   Undefined                                       |
   | Bit  5   |   Cassette Motor Control (0 = On, 1 = Off)        |
   | Bit  4   |   Cassette Switch Sense: 1 = Switch Closed        |
   | Bit  3   |   Cassette Data Output Line                       |
   | Bit  2   |   /CharEn-Signal (see Memory Configuration)       |
   | Bit  1   |   /HiRam-Signal  (see Memory Configuration)       |
   | Bit  0   |   /LoRam-Signal  (see Memory Configuration)       |
   +----------+---------------------------------------------------+
   Default Value is $37/55 (%00110111).

  (German-?)C128 only:

   +--------+-----------------------------------------------------+
   | Bit  6 |   ASCII/DIN-Switch (0=DIN, 1=ASCII)                 |
   +--------+-----------------------------------------------------+
   Default Value is $77/119 (%01110111).

  Flash_8 only:

   +--------+-----------------------------------------------------+
   | Bit  7 |   1 = 1 MHz, 0 = 8 MHz (if DIP1 closed)             |
   | Bit  6 |   (?)                                               |
   +--------+-----------------------------------------------------+
   Default Value is $37/55 (%00110111).

Kernal-Reference:

 ASL $01,X   : $B9A6
 BIT $01     : $F830 $F834
 INC $01,X   : $B9AA
 LDA $01     : $EA61 $EA6B $EA75 $F8AB $FBBF $FCCA
     $01,X   : $F5E6
     $0001,Y : $B8CB
 LDY $01,X   : $B991
 LSR $01,X   : $B89E
 ROR $01,X   : $B9AC $B9AE
 SBC $01,X   : $B8CE
 STA $01     : $EA79 $F8AF $FBC3 $FCCE $FDD7
     $01,X   : $B4DB
 STY $01,X   : $B997

    Previous Page / Next Page