Advanced Nintendo Entertainment System (ANES)

Enhancing the NES with Dual PPU Architecture

The ANES project is a hardware modification designed to push the graphical boundaries of the original Nintendo Entertainment System by integrating two Picture Processing Units (PPUs) instead of one.

Author's Note: I don't expect many people to actually undertake this build, so please be aware that the documentation may be somewhat incomplete or "half-assed" in certain areas.

If you prefer a software-based approach over soldering, you can experiment with this concept via a modified fork of the Mesen2 emulator.

🛠️ Hardware Requirements

To execute this mod, you will need components from both your primary console and a donor unit. The following table outlines the necessary Bill of Materials (BOM):

Qty	Location	Part Number	Description
2	U1, U2	`RP2C02`	PPUs (harvested from two consoles)
1	U3	`AS6C6264-55PCN`	Static RAM dedicated to PPU2
1	U4	`74LS373`	Address latch (from donor)
1	U5	`74LS139`	Demultiplexer (from donor)
1	U1	`EMS-26405`	40-pin wire wrap socket for PPU1
2	J1	—	20-pin female pin headers
1	U5/J3	—	16-pin socket for the `74LS139`
4	RN1	$10\text{k}\Omega$	1/4 watt EXT pull-down resistors
1	—	6x8cm board	Prototype board
1	U2	—	40-pin socket for PPU2 (Optional)
1	U3	—	28-pin socket for RAM (Optional)
1	U4	—	20-pin socket for latch (Optional)

🏗️ Build Process

The assembly can be broken down into the following sequence of operations:

Prepare the Prototype Board: The standard 6x8cm board is ~~perfectly sized~~ slightly too large and will block the expansion port. Trim it down before proceeding.
Component Harvesting: Desolder the RP2C02 (U5) from both your target console and the donor console.
Clear Space: Relocate or fold down capacitors that obstruct the placement of the dual-PPU board.
Header Installation: Solder the two 20-pin female headers into the original PPU footprint.
Board Assembly: Construct the dual-PPU board using the provided KiCad schematics and reference photos.
Demultiplexer Modification:
1. Take a 16-pin IC socket and remove pins 6, 7, 9, 10, 11, 12, 13, 14, and 15.
2. Mount this socket over the console's existing 74LS139, soldering only pins 1, 8, and 16.
3. Create the following jumper connections:
  - Socket Pin 2 $\rightarrow$ CPU Address Line A12
  - Socket Pin 3 $\rightarrow$ Console 74LS139 Pin 5
  - Socket Pins 4 & 5 $\rightarrow$ /CE pins of PPU1 and PPU2 respectively.
Final Integration: Plug the completed dual-PPU board into the female headers.