8255 PPI (060h - 063h)

Port A (060h)
        Keyboard scan code  or Diagnostic outputs

Port B (061h)
        PB.0    +Timer 2 gate speaker
        PB.1    +Speaker data
        PB.2    Spare
        PB.3    Read High or Low switches
        PB.4    -Enable RAM Parity check
        PB.5    -Enable I/O channel check
        PB.6    -Hold keyboard CLock low
        PB.7    -Enable keyboard/+Clear keyboard

Port C (062h)
        PC.0    Loop on post    (SW-1) or Display 0  (SW-5)
        PC.1    +Co-processor   (SW-2)    Display 1  (SW-6)
        PC.2    +Planar RAM 0   (SW-3)    # Drives 0 (SW-7)
        PC.3    +Planar RAM 1   (SW-4)    # Drives 1 (SW-8)
        PC.4    Spare
        PC.5    +Timer channel 2 out
        PC.6    +I/O Channel check
        PC.7    +RAM Parity check

Mode register (063h)
        Value set to 099h