PentoGraf-DivMMC-x2

DivMMC (Aurora clone) & DivMMC + Z-Controller with Dual ROM for PentoGraf computer.

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📋 Version Description

A complete hardware clone of the classic DivMMC by Aurora, adapted for the PentoGraf system bus slot.

Core: Original DivMMC logic.
Interface: SD card slot.
Compatibility: Full out-of-the-box compatibility with standard software and esxDOS operating system.
Differences from the original: Only the form-factor and edge connector pinout were modified to fit the PentoGraf expansion slot.

An advanced modification based on the DivMMC2ROM by Electrophysic project, adapted for the PentoGraf system bus slot.

Dual ROM Architecture: The board features two ROM chips. One ROM stores the standard firmware (esxDOS), while the second ROM acts as a hardware address decoder.
Z-Controller Support: Along with the standard DivMMC mode, the board features integrated hardware logic for the Z-Controller (an SD card interface highly popular among classic post-Soviet ZX Spectrum clones like Pentagon).
Simultaneous Operation: Both DivMMC and Z-Controller interfaces work in parallel and simultaneously. No manual toggling or switches are required.
Universal SRAM Footprint: The PCB layout features a combined DIP/SOP footprint, allowing you to use three different types of static RAM seamlessly without any jumpers (auto-detected):
1. AS6C4008 (512 KB, DIP-32 package)
2. IS61C1024 (128 KB, DIP-32 package)
3. K6X4008 (512 KB, SOP-32 package)
Versatility: The perfect choice for developers and enthusiasts seeking maximum compatibility with various modern and legacy software.

System Slot: Custom pitch and pinout designed specifically for the PentoGraf expansion slot.
Power Supply: +5V supplied from the system bus.
Supported OS/Software: esxDOS (for both DivMMC modes), Fatall / Wild Commander (WOS) (for Z-Controller mode).

Manufacturing: Go to the desired version folder, download the Gerber archive, and order the boards from any PCB manufacturer (JLCPCB, PCBWay, etc.).
Assembly: Solder components according to the interactive BOM and placement sheets. No jumper configuration is needed for RAM type selection.
Flashing Firmware:
- The DIV ROM image is identical for both hardware versions. Get the firmware binary here
- For dual SD card support (Dual ROM mode), flash this image into the ADR ROM: Download ROM
- For the DivMMC + Z-Controller mode, flash this image into the ADR ROM: Download ROM
SD Card Preparation:
- Format your SD card to FAT32.
- For DivMMC functionality: Copy the official esxDOS system directories (/SYS and /BIN) directly to the root of the card.
First Boot: Insert the controller into the PentoGraf expansion slot while the computer is powered off. Insert the prepared SD card and power on the system.

This project is distributed under the open-source MIT License.
Thanks to AlexEkb for the original and reliable discrete-logic DivMMC schematic design.
Special thanks to Electrophysic for the DivMMC2ROM project, which served as the hardware core for Version 2 of this controller.