>C=N RM=80 LM=3 TM=1 BM=66 J=N                                                            Fig. 5                          Cpm Adapter Board Mods for 256K Memory                                                                     2  |----\                                    2  |----\           |-------------| U31  \   3   ______       U27-8   >--------| U30  \   1     |          1  | 74LS32 |---> NUZ WR       74LS20        3  | 74LS02 O-------|     ZRW  >--| OR   /   New Status     Write Protect|-----| NOR  /                       |----/ incase we select   status for   |     |----/              5 |----\    above 64K we don't want  Ram          |-------------------| A15 --| U17  \   6   it Write protected                                   |     4 | 74LS32 |-----|     ------        A16             1  |----\        | A14 --| OR   /       | Remove Address    HD64180-29 >-------| U31P \   3  |       |----/   |-----| seclect if A16/17 A17             2  | 74LS32 |----|                | is active and Graphics  HD64180-30 >-------| OR   /      |                |  4  |----\  ram enabled                    |----/        |                |-----| U31P \   6        If A16 or A17 is High then memory|                   5  | 74LS32 |--> U17-9 above 64K is accesed  |----------|----------------------| OR   /    GRAPHEN       |------| 14     | 5  |----\                       |----/                    | U13  |--x     |----| U30  \    4                        ______            | 74LS | 15       6  | 74LS02 O---------|-------> U22-12  NO I/O            |  157 |-------------| NOR  /           |                                   |      |   NO I/O    |----/             |   10 |----\                       |------|   No I/O map selected if A16/17|------| U22  \  8                           is active        ___               9  | 74LS00 O----> A15                              U18-2 A15    >-------------| NAND /   On Expansion                                                     |----/     Buss Conn.                                                                  For Corvus                                                                  Interface                                                                   Card.                          256K Memory Mux                                                                                                                                             560 Ohm                                                              |-----\/\/\/--------> GND                                                   |    |---------|     Resistors are for the Z80H mode, we                    |  5 | U113    |  7 don't want then to be high ever.           HD64180-29 >-|----| 74LS157 |---------> 256K Ram Pin 1                                      6 | Mult    |    This is an extra on U113 and has all of    HD64180-30 >-|----|  plexer | the nessary select lines                                   |    |---------|                                                            |   Main Cpu Board                                                          |      560 Ohm                                                              |-----\/\/\/--------> GND                                                                                                                 