LENINGRAD-2-48k/ROM/rom.md
Alex-2-Graf 3077e4bd44 eng
2026-06-21 11:51:01 +02:00

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\# ROM Selection and Configuration Guide
> \[English](ROM.md) | \[Русский](ROM.ru.md)
The "Leningrad-2 2025 Revision" PCB provides flexible options for installing ROM chips. You can use standard vintage EPROMs or modern alternatives depending on your goals.
\## Supported ROM Chips
1\. \*\*Standard 48K Setup:\*\*
  \* \*\*2764 (К573РФ4/6)\*\* — Requires two separate chips. One holds the lower part of the ROM (Basic-48), and the other holds the upper part.
  \* \*\*27128 (К573РФ8)\*\* — A single chip that holds the entire 16 KB ZX Spectrum 48K ROM.
2\. \*\*Expanded Setup (with TR-DOS / BDI):\*\*
  \* \*\*27256\*\* — Allows you to store two different versions of TR-DOS or customized firmware.
  \* \*\*W27E256\*\* — A modern, electrically erasable (EEPROM) drop-in replacement for the 27256. Highly recommended for easy flashing.
\---
\## Jumper Settings for ROM
\* \*\*JP4 (ROM Type Selection):\*\*
  \* \*\*Short\*\* this jumper if you are installing \*\*two 2764\*\* chips.
  \* \*\*Leave Open\*\* if you are using a single \*\*27128\*\* or \*\*27256\*\* chip.
\* \*\*J12 (TR-DOS Firmware Selection):\*\*
  \* Active only when using a \*\*27256\*\* ROM. It switches between the two firmware banks stored on the chip.
\* \*\*JP5JP9 (Memory Expansion Support):\*\*
  \* Must be soldered/shorted to ensure correct address lines routing for future memory expansions and multi-bank ROM configurations.