Z80Bus Memory Module

Description

A larger, upgraded version of my ROM/RAM module. The Z80Bus system supports up to 8 modules simultaneously (ID=0 to ID=7).

Module ID=0 is the primary module and must always be installed.

Modules ID=1 through ID=7 function as secondary expansion.

Hardware Capabilities (Per Module)

Slot 1: Dedicated 512 KB ROM slot.

Slot 2: Flexible 512 KB slot (supports either ROM or RAM).

High RAM: Supports 32 KB High RAM, which can only be populated on the primary module (ID=0).

Configuration Examples

1. SG-1000 Setup

Module ID=0 (Primary): Configured with 1024 KB ROM and 32 KB High RAM.

Module ID=1 (Secondary): Configured with 1024 KB ROM (no RAM).

2. Standard CP/M Setup

Module ID=0 (Primary): Configured with 512 KB ROM, 512 KB RAM, and 32 KB High RAM.

Jumper Settings (J5)

Important Hardware Note: A14 and A15 are swapped specifically for the RAM configuration.

For RAM Configuration: Close pins 1-2 and 3-4.

For SST39SF040 Flash ROM: Close pins 2-3 and 4-5.

In-System Flash Programming: Write protection for the SST39SF040 is enabled by default. To program the flash chip directly on the board, connect pins 1 and 4.