PRT | 76543210 |
00  | 00****** |
01  | 00000*** | WS mode
01  | ******** | WSC mode
04  | 000***** | WS mode
04  | 00****** | WSC mode <-- added bit sticks until next write
05  | 0******* |
06  | ******** |
07  | 0***0*** | WS mode
07  | ******** | WSC mode <-- added bits stick until next write
15  | 00****** |
16  | ******** | WS+ | Vtotal-1 | initial = 09Eh (158)
17  | ******** | WS+WSC | Vblank | initial = 09Bh (155) | Screen shuts off at 90h and vtotal
17  | 00000000 | SC
18  | 00000000 |
19  | 00000000 |
1A  | ???????? | has something to do with bit0
                 when b0 set, only top line displays???
                 screen is OFF otherwise!
                 WSC doesn't give any weird returns after fixing the bit
                 SC puts 3C here for a while???
1B  | 00000000 |
PAL | 0***0*** | All of them~
40-5F|00000000 | without DMA enabled
40  | *******0 |
41  | ******** |
42  | 0000**** |
43  | 00000000 |
44  | *******0 |
45  | ******** |
46  | *******0 |
47  | ******** |
48  | !*000000 |
49  | 00000000 |
4A  | ******** |
4B  | ******** |
4C  | 0000**** |
4D  | 00000000 |
4E  | ******** |
4F  | ******** |
50  | 0000**** |
51  | 00000000 |
52  | !*0***** |
53  | 00000000 |
54-5F|00000000 |
60  | ***0*0** | initial = 0Ah
61  | 00000000 |
62  | 1000000* | SC | bit0 turns the console off lmao
62  | 0000000* | WSC | bit0 turns the console off lmao
63  | 00000000 |
64  | 00000000 |
65  | 00000000 |
66  | 00000000 |
67  | 00000000 |
68  | 00000000 |
69  | 00000000 |
6A  | ******** |
6B  | 0**0**** |
6C  | 00000000 |
6D  | 00000000 |
6E  | 00000000 |
6F  | 00000000 |
70  |  FIXED?  | initial = SC=0D0h WSC=0
71  |  FIXED?  | initial = SC=077h WSC=0
72  |  FIXED?  | initial = SC=0F7h WSC=0 1783 
73  |  FIXED?  | initial = SC=006h WSC=0
74  |  FIXED?  | initial = SC=0E2h WSC=0 2786
75  |  FIXED?  | initial = SC=00Ah WSC=0
76  |  FIXED?  | initial = SC=0EAh WSC=0
77  |  FIXED?  | initial = SC=0EEh WSC=0
78  | 00000000 |
79  | 00000000 |
7A  | 00000000 |
7B  | 00000000 |
7C  | 00000000 |
7D  | 00000000 |
7E  | 00000000 |
7F  | 00000000 |
FRQH| 00000*** |
FRQL| ******** |
8F  | ******** |
91  | !000**** |
94  | 0000**** |
95  | ******** |
WS:
96  | ******** |
97  | 000000** |
98  | ******** |
99  | 000000** |
9A  | 00000111 |
9B  | 11111110 |
9C  | 11111111 |
9D  | 11111111 |
WSC+SC:
96  | 00000000 |
97  | 00000000 |
98  | 00000000 |
99  | 00000000 |
9A  | 00000000 |
9B  | 00000000 |
9C  | 00000000 |
9D  | 00000000 |
9E  | 000000** |
9F  | 00000000 |
A0  | 1++++*11 | SC's WS mode
A0  | 1000**11 | SC's WSC mode + WSC
A0  | 1000**01 | WS
A1  | 00000000 |
A2  | 0000**** |
A3  | 0000**** | bit3 barfs all over serial??
AC  | 0000000* | bit0 turns the console off lmao
AD  | 00000000 |
AE  | 00000000 |
AF  | 00000000 |
B0  | *******0 | WSC + SC
B0  | *****011 | WS
B5  | 0***!!!! |
B7  | 000*0000 |
B8  | 00000000 |
B9  | 00000000 |

0,1 = fixed
* = holds data
+ = locking set
! = readonly data

Unit select:
&01E0 == 0000: VDP(1)
&01E0 == 0020: VDP(2)
&01E0 == 0040: DMA (WSC only)
&FFE0 == 0060: SYS?
               6A-6B is &01E0
&01E0 == 0080: SND
&01E0 == 00A0: SYS?
               A0-A1 is &FFFF
               AC-AF is &FFFF
               B8-BF is &FFFF
&FFC0 == 00C0: CART

&C000 != 0: NOP
WSC+: ELSE: 0
WS: ELSE: NOP

Memory:
In WS mode on WSC, 4000-FFFF return NOP!
Same as WS itself!