Commodore PLUS/4 & C16 PLA Inputs I0 F7 X X - X 1 1 1 X 1 I1 phi 0 1 1 - X 1 1 1 X 1 I2 A15 1 1 - 1 1 1 1 X X I3 A4 0 0 - X 1 1 1 X X I4 A5 0 1 - X 1 0 0 X X I5 A6 0 0 - X 0 1 0 X X I6 A7 0 0 - X 0 1 0 X X I7 A12 1 1 - 1 1 1 1 X X I8 MUX X X - X X X X 1 X I9 A14 1 1 - 1 1 1 1 X X I10 A8 1 1 - 0 1 1 1 X X I11 A9 0 0 - 0 0 0 0 X X I12 A13 1 1 - 1 1 1 1 X X I13 A11 1 1 - 1 1 1 1 X X I14 A10 1 1 - 1 1 1 1 X X I15 -RAS X 0 - X 0 0 0 X 0 Outputs F0 -? X 0 1 X X X X X X F1 phi 2 X X 0 X 1 1 1 X 1 F2 -USER X X 1 X X X 0 X X F3 -6551 0 X 1 X X X X X X F4 ^ADDR CLK X X 1 X X 0 X X X F5 -KEYPORT X X 1 X 0 X X X X F6 KERNAL X X 0 1 X X X X X F7 I0 X X 0 X 1 1 1 1 1 Legend 0 low 1 high X input ignored; output unchanged - indicates the default condition. NOTE: Pin F0 is not connected to anything but is programmed. It's use is unknown. NOTE: Pins I0 and F7 are connected together, apparently to provide a timing delay. Commodore PLUS/4 & C16 MEMORY ------ CPU & Screen Read ------ - Character Set -- Write Read RAM Read ROM Read RAM Read ROM 0000-7FFF RAM RAM RAM RAM 8000-BFFF RAM RAM LO ROM RAM LO ROM C000-FBFF RAM RAM HI ROM RAM HI ROM FC00-FCFF RAM RAM KERNAL RAM KERNAL FD00-FD0F (6551) (6551) (6551) FD10-FD1F CAS(USER) CAS(USER) CAS(USER) FD20-FD2F ? ? ? FD30-FD3F KEYBOARD KEYBOARD KEYBOARD FD40-FDCF FDD0-FDDF ROM LATCH FDE0-FEFF FF00-FF1F TED TED TED TED TED FF20-FF3D RAM RAM HI ROM RAM HI ROM FF3E ROM SELECT HI ROM HI ROM FF3F RAM SELECT HI ROM HI ROM FF40-FFFF RAM RAM HI ROM RAM ( ) NOT AVAILABLE ON THE C16 NOTE: FD20-FD2F is accessed by the kernal power-up routines, but nothing inside the PLUS/4 or C16 is at this address. LO ROM and HI ROM are determined by writing to the appropriate ROM LATCH address. ROM LATCH LO ROM HI ROM FDD0 BASIC KERNAL FDD1 (FUNCTION LO) KERNAL FDD2 CARTRIDGE 1 LO KERNAL FDD3 CARTRIDGE 2 LO KERNAL FDD4 BASIC (FUNCTION HI) FDD5 (FUNCTION LO) (FUNCTION HI) FDD6 CARTRIDGE 1 LO (FUNCTION HI) FDD7 CARTRIDGE 2 LO (FUNCTION HI) FDD8 BASIC CARTRIDGE 1 HI FDD9 (FUNCTION LO) CARTRIDGE 1 HI FDDA CARTRIDGE 1 LO CARTRIDGE 1 HI FDDB CARTRIDGE 2 LO CARTRIDGE 1 HI FDDC BASIC CARTRIDGE 2 HI FDDD (FUNCTION LO) CARTRIDGE 2 HI FDDE CARTRIDGE 1 LO CARTRIDGE 2 HI FDDF CARTRIDGE 2 LO CARTRIDGE 2 HI ( ) NOT AVAILABLE ON THE C16