     $D0B8/53432/SCPU+72:   Software 1 MHz-/Master 1Mhz Flag

       +-------+--------------------------------------------------------+
       | Bit 7 |   Software 1 MHz Flag: 1 = 1 MHz                       |
       | Bit 6 |   Master 1 MHz Flag: 1 = 1 MHz via any source          |
       +-------+--------------------------------------------------------+

         This register is read only with hardware registers disabled,
         Read/Write with hardware registers enabled, write access reserved
         for system only.