4 A4 A5 A6 A7 A15 NC M1 MREQ IOREQ GND
5 RFSH NC NC NC /IACK UARTENP /UARTEN /RAMEN /ROMEN VCC
7 ROMEN = /MREQ * RFSH * /A15
8 RAMEN = /MREQ * RFSH * A15
9 UARTEN = /IOREQ * /A7 * /A6 * /A5 * /A4
10 UARTENP = /IOREQ * /A7 * /A6 * /A5 * /A4
14 Z80 computer 2 glue logic and address decoding
15 /ROMEN enables the ROM for memory cycles from 0000h to 0fffh
16 /RAMEN enables the RAM for memory cycles from 1000h to ffffh
17 /UARTEN enables the DUART for I/O cycles from port 0 to 15
18 UARTENP is the negation of /UARTEN, needed for the DUART wait state logic
19 /IACK signifies an interrupt acknowledge cycle