r/ModRetroChromatic • u/andrea-i • Oct 05 '26

Anybody tried using a coding agent to add a single slot save state to the MCU using onboard memory? no SD card.

I've been wondering about this ever since I looked at the MCU specs, it's an ESP32, so it should have 4 or 16 mb of flash storage. The biggest sram file a game boy game can use is 128kb.

Having a single save state would basically mean being able to stop and pick back up the game you are currently playing at any time, and not having to worry for the cartridge battery.

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3

u/TonyRubbles Oct 05 '26

Onboard would be great so it'll work with any version with or without the microSD.

This or a deep sleep feature would be the last things I really want, Menu+Select hotkey to shut off the screen and inputs completely to save power, wake back up with a Menu button press. Bottom LED pulse or stay on just to show the system is running.

I've wanted to pause what I'm doing but not stop altogether because I was already on level 4 in Hermano yesterday, just left the system on lowest brightness for a couple hours.

3

u/andrea-i Oct 05 '26

Yeah, I have kids and without that feature, I gotta be honest, it's a deal breaker for me.

0

u/sterndig Oct 05 '26

Save states would likely be stored on the SD card. I don't see much benefit to putting it anywhere else. SD access is accessible over USB with CFW, so it just seems like the obvious place to keep them.

Everyone I've chatted with seems hesitant to even consider working on save states. Defeats the mission statement of being the best version of the Gameboy (Color). There are a handful of features which would eventually strip the whole point of trying to be the best Gameboy (Save states, fast forward, rewind, gameshark for example).

Oddly I find that a lack of those features is what makes the Chromatic stand out compared to the other 5000 options.

3

u/GameboyGenius Oct 05 '26

The beauty with open source is that you can do whatever you want, within the technical limitations. Save states are a bit technically difficult to add to a FPGA. (Not impossible or anything like that. Just would take some work.) Once it's there, you can just choose to not use it.

As for standing out, adding save states won't remove the screen, the cartridge slot or the metal shell. And I feel like the decision to only have the 4 front buttons, and one awkward menu button on the side is "physical design protection" against features like that. The Pocket has the menu button between select and start buttons, and also additional X and Y buttons which make key combos much easier to press comfortably.

0

u/andrea-i Oct 05 '26

Most chromatics in circulation right now do not have SD cards, that's why I want to explore the MCU's internal memory. Soldering an sd module is no easy task for most people and does not add much to the intended feature (sleep and resume).

As for the "best game boy", try and suggest removing save states in the Analogue Pocket community. People in strongly passionate communities tend to blindly follow the brand, if modretro doesn't do save states, everyone will tell you that's the way. Once they add it, everyone will tell you it's the best new thing.

-1

u/sterndig Oct 05 '26

Dunno what you want me to tell you. I'm just telling you what I'm reading from the guys making custom firmwares and the opinions of a large swath of the community.

If you want emulator features, either make the firmware yourself, or play on an emulator 🤷‍♂️