exc

README.en.md

@@ -0,0 +1,84 @@
+# LENINGRAD-2-48k
+
+## Leningrad-2. Russian ZX Spectrum clone. Schematics and PCB.
+
+> [English](README.en.md) | [Русский](README.md)
+
+"Leningrad-2" is a home personal computer compatible with the ZX Spectrum, created in 1989 as an evolution of the popular "Leningrad" model. It is an improved version of the legendary first model, which was highly regarded for its simple circuitry. 
+
+"Leningrad-2" retained this elegant and simple design, making it easy to assemble and tune. The computer is powered by a Z80 processor and features 48 KB of RAM implemented on Soviet KR565RU5 (КР565РУ5) chips.
+
+Along with its predecessor, "Leningrad-2" became one of the most widespread ZX Spectrum clones in the former USSR, as hobbyists could easily build it at home using widely available radio components. A key advantage of "Leningrad-2" over other contemporary clones was its dedicated expansion slot.
+
+***
+
+### Project History
+
+After building a "Radio 86RK" and an Odessa-designed clone (sadly, the schematics for the latter are lost), I decided to assemble the "Leningrad-2". Just a month later, I expanded it to 128K and added a Beta Disk Interface (BDI). 
+
+To afford two 5.25-inch floppy drives, I spent the summer of 1990 working with a student construction brigade. This computer served me faithfully throughout my entire university years. It handled countless complex calculations, traveled to many places — including the Chernobyl Nuclear Power Plant (ChNPP) — and remains fully functional to this day.
+  
+![](Foto/%D0%9F%D1%80%D0%B0%D0%B4%D0%B5%D0%B4%D1%83%D1%88%D0%BA%D0%B0-1990.jpg)  
+  
+The original "great-grandfather" board will soon be housed in a brand-new case.
+
+### Leningrad-2 2025 Revision
+
+In 2025, I decided to redesign the PCB to match modern realities. I wanted to build in expansion capabilities right from the start, avoiding any future track-cutting or messy wire-wrap modifications (MGTF wire). 
+  
+![](Foto/L2_1.00.jpg)  
+  
+
+As a result, the **"Leningrad 2 2025"** was born. The main upgrades include onboard integration of:
+*   The **ZX_RGBI2VGA-HDMI** converter by AlexEkb.
+*   The **AY-3-8910** sound chip.
+*   Minor improvements for future expansions.
+
+Alongside this, I designed a Gerber adapter for Nemo-bus and ZX-bus. This allows the connection of various expansion cards, such as the Cosmo Card by Igor ZXKM.  
+  
+![](Foto/Back_L2_Nemo_Spec.jpg)  
+  
+![](Foto/L2_1.00%2BKK.jpg)  
+  
+The results completely met expectations. Following real-world testing and minor cosmetic tweaks, I released a few revisions:
+
+*   **Revision 1.01** ([Schematics](Export/Leningrad%202%2048k%202025%201.01.pdf) / [Gerber](Gerber/Leningrad%202%2048k%202025%201.01%20GERBER.zip)) — *Initial release. No bugs found, but updated based on community feedback.*
+*   **Revision 1.02** ([Schematics](Export/Leningrad%202%2048k%202025%201.02.pdf) / [Gerber](Gerber/Leningrad%202%2048k%202025%201.02%20GERBER.zip)) — *The latest current revision.*
+
+---
+
+## Assembly & Jumper Settings
+
+Generally, assembly and tuning are straightforward. Here is the configuration guide for the onboard jumpers:
+
+*   **JP1, JP2, JP3**: Short these if you are installing a VGA connector. Leave them open for HDMI. If using HDMI, make sure all resistors `R24-31` are replaced with 270 Ohm.
+*   **J9**: Used to disconnect power from the RP2040-Zero board during firmware flashing.
+*   **JP4**: Short this if you are installing two 2764 ROMs.
+*   **JP5–JP9**: Solder all of these. They are required for future memory expansions.
+*   **JP10, JP11**: Solder on the left side. You only need to resolder them if you expand the RAM to 256K using 41256 (РУ7) chips.
+*   **J12**: Used to select the BDI firmware if you install a 27256 ROM containing two versions of TR-DOS.
+*   **CAS1 Pin**: Required for expanding the memory to 128K using two rows of 4164 (РУ5) chips.
+
+---
+
+## ROM & Video Configuration
+
+*   **ROM**: Detailed ROM selection guide can be found [here](ROM).
+*   **VGA**: RGB2VGA converter setup instructions are available [here](VGA).
+
+---
+
+## Recommended Accessories
+
+* [BDI-TR-DOS](https://github.com/Alex-2-Graf/Leningrad2-BDI-TR-DOS)
+* [DivMMC](https://github.com/Alex-2-Graf/Leningrad2-DivMMC)
+* [Memory Expansions and AY/TS](https://github.com/Alex-2-Graf/Leningrad2-Upgrade-Kit)
+* [LGT-Turbo-Sound-emulator](https://github.com/Alex-2-Graf/LGT-Turbo-Sound-emulator)
+* [ZX-EQ Nemo-bus Edition](https://github.com/Alex-2-Graf/ZX-EQ)
+
+---
+
+## Credits & Acknowledgments
+
+*   **Alex Ekb** — for the amazing RGB2VGA converter design.
+*   The **Scorpion ZS & Leningrad** community, and all my friends who supported this project.

README.md

@@ -1,6 +1,8 @@
 # LENINGRAD-2-48k  
 ## Leningrad-2. Russian ZX Spectrum clone. Schematics and PCB.  
   
+> [English](README.en.md) | [Русский](README.md)  
+  
 «Ленинград-2» — это бытовой персональный компьютер, совместимый с ZX Spectrum,  
 созданный в 1989 году как дальнейшее развитие популярной модели «Ленинград».  
 Это усовершенствованная версия легендарной первой модели, которая отличалась простотой схемы.  

ROM/readme.md

@@ -1,4 +1,7 @@
-# Прошивки для проекта
+# Прошивки для проекта  
+  
+> [English](rom.md) | [Русский](readme.md)
+>   
 ## Версия с двумя ПЗУ по 8кб (2764, К573РФ4А)
 Прошиваем 48k-0 и 48k-1 соответственно.  
 Не забываем установить перемычку JP4.

ROM/rom.md

@@ -0,0 +1,55 @@
+# ROM Selection and Configuration Guide
+
+
+> [English](rom.md) | [Русский](readme.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.
+
+\* \*\*JP5–JP9 (Memory Expansion Support):\*\* 
+
+  \* Must be soldered/shorted to ensure correct address lines routing for future memory expansions and multi-bank ROM configurations.
+
+
+

VGA/readme.md

@@ -1,5 +1,7 @@
 # Файл прошивки конвертера RGB-VGA/HDMI  
   
+> [English](vga.md) | [Русский](readme.md)  
+  
 Прошивка [тут](RGB2_VGA_HDMI_v0.3.2_ZERO.UF2)  
   
 ## Скриншоты правильной установки параметров захвата  

VGA/vga.md

@@ -0,0 +1,29 @@
+# Video Configuration & RGB2VGA Setup
+
+> [English](vga.md) | [Русский](readme.md)
+
+The Leningrad-2 2025 Revision features an integrated onboard **ZX_RGBI2VGA-HDMI** converter designed by AlexEkb. This converter uses a powerful Raspberry Pi **RP2040-Zero** board to upscale the vintage ZX Spectrum video signal to modern displays.
+
+## Selecting Output: VGA vs. HDMI
+
+The board can output video via either a standard VGA connector or an HDMI port.
+
+### 1. HDMI Mode (Recommended)
+* **Jumpers JP1, JP2, JP3:** Must be left **OPEN**.
+* **Resistors R24 to R31:** You **MUST** replace the standard resistors with **270 Ohm** values to ensure proper signal voltage levels for HDMI stability.
+
+### 2. VGA Mode
+* **Jumpers JP1, JP2, JP3:** Must be **SHORTED**.
+* Use standard resistor values as specified in the original schematic.
+
+---
+
+## Flashing the RP2040-Zero Firmware
+
+To flash or update the video converter firmware via the onboard USB port, follow these crucial safety steps:
+
+1. **Disconnect System Power:** Turn off the main power supply of the Leningrad-2 computer.
+2. **Open Jumper J9:** Open/remove the **J9** jumper. *Crucial:* This completely isolates the RP2040-Zero power lines from the main computer board, preventing back-powering issues and potential hardware damage during flashing.
+3. **Connect USB:** Connect a USB-C cable from your PC to the RP2040-Zero.
+4. **Flash:** Hold the `BOOT` button on the RP2040-Zero, plug it in, and drop the `.uf2` firmware file onto the mounted drive.
+5. **Restore:** Unplug the USB cable, **close/solder J9** back, and power on the computer.