DreamPotato

KO | EN

gitlite — search

#javascript #hacktoberfest #android #machine-learning #linux #docker #java #awesome #kubernetes #awesome-list #pytorch #mcp #openai #ios

(★ 63)

An emulator for the Dreamcast VMU

DreamPotato Latest Version Download

Download Latest Version (.zip)

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# DreamPotato

DreamPotato is a Dreamcast VMU emulator currently in beta.

> [!WARNING]
> When opening a `.vmu` or `.bin` file, the emulator will modify the file on disk while running in order to persist changes, such as save file changes on the memory card, saving your progress in minigames, or when using the Load State command.
> Consider making copies of VMU files before using them to avoid any chance of corrupting your saves.
> `.vms` files opened in the emulator will not be modified.

[Download Latest Release](https://github.com/RikkiGibson/DreamPotato/releases/latest)

See [compatibility.md](compatibility.md) for the current compatibility status of various games.

## Flycast Integration

[![DreamPotato Flycast Integration Demo](https://raw.githubusercontent.com/RikkiGibson/DreamPotato/main/docs/images/demo-video-thumbnail.png)](https://www.youtube.com/watch?v=EN8Y3UX_TDM)

DreamPotato can connect to [Flycast](https://github.com/flyinghead/flycast) to support an experience similar to using a real Dreamcast and VMU together.

**NOTE**: The latest Flycast 2.6 stable release has a known issue with DreamPotato. Currently it's necessary to use a [master branch build](https://flyinghead.github.io/flycast-builds/) of Flycast. At time of writing, the build from 2026-01-28 (commit 21eb24f) is known to work.

Instructions:
1) Open the Flycast controller settings. Enable "**Use Physical VMU Memory**". Enable "**Use Network Expansion Devices**" for the controller port you want to use to connect.
2) Once both Flycast and DreamPotato are running, start a game in Flycast. After a moment, the swirl icon should appear in the DreamPotato menu bar indicating things are connected.
3) If you get disconnected, pause Flycast and hit the Connect button to reconnect.

Additional notes/caveats:
1) DreamPotato defaults to connecting to slot A1. You can go into the settings and change this if you wish.
2) If you disable **Use Physical VMU Memory**, then Flycast will use its own internal VMU files for saving/loading games. DreamPotato will still display VMU graphics in that case.
    - When loading state in Flycast, Use Physical VMU Memory will be temporarily disabled. You'll need to pause the game and disconnect/reconnect DreamLink in order to resume using DreamPotato's VMU memory.
2) DreamPotato will "take over" all the expansion devices for a given controller. So, if you want to do stuff like copy between Flycast-managed and DreamPotato-managed VMUs, you'll have to put them in separate controllers.
3) DreamPotato does not play sound while docked to a controller. You should leave the Flycast VMU sound setting enabled if you want that. (DreamPotato *does* play sound in standalone mode.)
4) If you want to use DreamPotato with multiple ports, you can launch multiple instance, and set a different Dreamcast Slot setting for each one.
5) In Chao Adventure, you need to hit Mode to exit the game before inserting the VMU, or your progress may not be saved.

## Usage

Download the latest bits from the [Releases](https://github.com/RikkiGibson/DreamPotato/releases) section.

### Default Key Mappings
- W - Up
- A - Left
- S - Down
- D - Right
- K - A
- L - B
- I - Mode
- J - Sleep
- Insert - Dock/Eject VMU to Dreamcast controller
    - You can also hold the Sleep button for 1 second to toggle docking/ejecting the VMU.
- F5 - Save State
- F8 - Load State
- F10 - Pause/Resume
- Tab (hold) - Fast Forward

### Open Folder

DreamPotato [dev build](https://github.com/RikkiGibson/DreamPotato/actions/runs/27885462097) has "Open Folder" and "Save As Folder" commands inspired by the "GCI Folder" support in Dolphin. When a folder is opened, DreamPotato loads all the `.vmi`/`.vms` files found in it. When the VMU's file contents change during gameplay, DreamPotato will automatically update the corresponding files in the folder.

Notes:
- "Save As Folder" is a convenient way to extract individual `.vmi`/`.vms` saves from your `.vmu`/`.bin` memory card file.
- You can rename the `.vmi`/`.vms` file pairs whatever you want, as long as the filenames match. DreamPotato will continue to pick them up and the on-VMU filenames will be preserved.
    - For example, if I have `S.ARCADIA001.vms` and `S.ARCADIA001.vmi` files for Skies of Arcadia, I could rename them to `My file.vms` and `My file.vmi`, and the game will continue to recognize them as an `S.ARCADIA001` file on the VMU.
- You can put any non-`.vmi`/`.vms` items in the folder you want and DreamPotato will ignore them.
- DreamPotato doesn't watch the opened folder, so if you manually make changes in it, you need to reopen the folder in DreamPotato for the changes to get picked up.
- It's recommended to "Save As Folder" to a folder which doesn't already contain any `.vmi`/`.vms` files in it. If you do, files might get overwritten, or other conflicts could occur in the folder, which you'll have to clean up manually.
- `fs_root.bin` contains file system metadata as well as the VMU's color and icon (for display in the Dreamcast BIOS). If you delete it, it will be re-created with default settings.

### Configuration

General configuration options include:
- `AutoInitializeDate`: bool, default true. If true, skips the startup beep and date setup, and uses your computer's clock to initialize the VMU's clock. Specify false if you want to use the date setup sequence as you would when installing batteries with real hardware.
- `AutoDockEject`: bool, default true. If true, automatically docks the VMU when Flycast is connected, and ejects it when Flycast is disconnected.
- `AnyButtonWakesFromSleep`: bool, default true. If true, any button will wake the VMU from sleep. If false, only the sleep button will do that.

Key and button mappings can be changed in Settings -> Keyboard Config / Gamepad Config.

## Building

- Install a .NET SDK 9 matching the version in `global.json`.
    - Easiest: install [`dotnetup`](https://github.com/dotnet/sdk/tree/release/dnup/documentation/general/dotnetup), then run `dotnetup` in this folder.
    - Alternatively: [download](https://dotnet.microsoft.com/en-us/download/dotnet) and run .NET SDK from Microsoft's website.
- Copy your `american_v1.05.bin` VMU ROM into `src/DreamPotato.MonoGame/Data/`.
- Build everything: `dotnet build`.
- Run the emulator: `dotnet run --project src/DreamPotato.MonoGame`.
- Run tests: `dotnet test`

## Project Overview

Under `src/`:
- `DreamPotato.Core` is where the emulator implementation resides.
- `DreamPotato.Tests` includes unit tests for the emulator implementation.
- `DreamPotato.MonoGame` is the front-end, including UI and config file handling.
- `dreampotato-vscode` is the VS Code extension--in *very* barebones/"alpha" state.
    - Currently, it contains only a TextMate grammar for LC86k assembly.

## Why write a new emulator?

The biggest reason was: I was interested in timing-based luck manipulation in Pinta's Quest, which requires emulating the game at a very similar speed to real VMU hardware. I found that existing emulators did not run the game at a similar enough speed to real hardware to allow the same timings to work. I thought that writing a new emulator from scratch would be a good way to learn the hardware well enough to get to the bottom of how to do that.

## Acknowledgements

Thanks to the following individuals, whose invaluable work on VMU emulation and reverse engineering helped make DreamPotato possible.

- Falco Girgis, author of [ElysianVMU](http://evmu.elysianshadows.com/)/[libevmu](https://github.com/gyrovorbis/libevmu) and extensive [documentation](https://vmu.elysianshadows.com/index.html) of VMU internals.
- Dmitry Grinberg for his [VMU hackery](https://dmitry.gr/index.php?r=05.Projects&proj=25.%20VMU%20Hacking) project.
- Walter Tetzner, author of the [waterbear](https://github.com/wtetzner/waterbear) assembler/disassembler.
- Homebrew developers jvsTSX and Jahan Addison for publishing [homebrew](https://github.com/jvsTSX/VMU-MISC-CODE) [software](https://github.com/jahan-addison/snake) which was very helpful for testing the emulator.

DreamPotato

DreamPotato Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

DreamPotato

DreamPotato Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

Download README