Left '161: can't tell much, other than that its outputs probably connect to the left '157
Left '157: set up to emit either (output of right '157) or (value in left '161)
Right '157: set up to emit either (value of CPU address bus) or (lower three bits of right '161)
Right '161: definitely latches CPU A0-A3 when so instructed by the PAL
PAL:
Code: Select all
1: ?A10?
2: /ROMSEL
3: A14
4: A13
5: A12
6: ?A11?
7: ?R/W?
8: ?PPU A11?
9: ?PPU A10?
10: Gnd
20: +5V
19: Latch1
18: Mux1
17: Latch2
16: ?Mux2?
15: PRGROM /OE
14: M2
13: ?PRGRAM /CE?
12: ?CIRAM A10?
11: Latch2Q3