84PCE:Ports:B000 Unknowns

Port	Default	Bits	Information
B000	64	??	Value seems fixed
B001	64	??	Value seems fixed
B002	61	??	Value seems fixed
B003	4C	??	Value seems fixed
B004	00	FF	Ports B004-B007 latch value written
B008			Ports B008-B00B always read 0
B00C	00	77	Writing FF latches to 63, though you can manually write 67.
B00D	00	FF	Ports B00D-B00F latch value written
B010			Ports B010-B013 always read 0
B014	00	FF	Ports B014-B01B latch value written
B01C			Ports B01C-B01F always read 0
B020	FF	FF	Some kind of PWM scaler? BL goes to full-bright if less than B024. If less than FF, BL gets dimmer.
B021	00	FF	BL goes to full-bright if not zero
B022	00	0F	BL goes to full-bright if not zero, returns to normal after about 1 second when reset to zero
B023	00	??	Always zero
B025	00	FF	BL goes to full-bright if not zero
B026	00	0F	BL goes to full-bright if not zero