SummerCart64 - a fully open source N64 flashcart

For non-technical description of the SummerCart64, please head to the https://summercart64.dev website!

Features

• ROM and Save Memory On-board
• 64 MiB SDRAM memory for game and save data (enough memory to support every retail game without compromise)

• 16 MiB FLASH memory for bootloader and extended game data (with extended memory flashcart supports game ROMs up to 78 MiB)

• Game Saves

• EEPROM 4k/16k, SRAM and FlashRAM save types with an automatic writeback to the SD card (no reset button press required)

• Hardware-Dependent Game Features

• 64DD add-on emulation

• Battery backed real time clock (RTC)

• Menu

• Dedicated open source menu written specifically for this flashcart - N64FlashcartMenu

• Game Development

• ~23.8 MiB/s peak transfer rate SD card interface
• ~23.8 MiB/s peak transfer rate USB interface for data upload/download and debug functionality
• PC app to access the flashcart features:
  • Game/save data upload/download
  • Feature enable control
  • Debug terminal
  • Access to the SD card
  • Firmware update
• UNFLoader support
• IS-Viewer 64 debug interface (fixed 64 kiB buffer with a movable base address)
• 8 kiB on-chip buffer for general use
• Status LED and button for general use
• UltraCIC_C emulation with automatic region switching and programmable seed/checksum values

• N64 bootloader with support for IPL3 registers spoofing and loading menu from SD card

• Cartridge Production

• Initial programming via UART header or via dedicated JTAG/SWD interfaces
• 3D printable shell

Documentation

• Quick startup guide
• Memory map
• N64 commands
• USB interface
• Config options
• FW and SW info
• Build guide

How do I get one?

Most up to date information about purchasing/manufacturing options is available on https://summercart64.dev website!

If you want to order it yourself then I've prepared all necessary manufacturing files on the PCBWay Shared Project site.

Be careful: this is an advanced project and it is assumed that you have enough knowledge about electronics. Selecting wrong options or giving PCB manufacturer wrong information might result in an undesired time and/or money loss. Boards also come unprogrammed from the manufacturer - you need to do initial programming step yourself after receiving the board. Price of the components is not included in the initial quote at the checkout - manufacturer will contact you later with updated price. To avoid problems please read both build guide and description on the shared project page in full. If you have even slightest doubt about the ordering or programming process, it is better to leave it to someone experienced - ask in the N64brew Discord server if that's the case.

Full disclosure: for every order made through this link I will receive 10% of PCB manufacturing and PCB assembly service cost (price of the components is not included in the split). This is a great way of supporting further project development.

If you don't need a physical product but still want to support me then check the sponsor links on the official website.

High-level flashcart block diagram

Finished example

Acknowledgement

This project wouldn't be possible without these contributions:

• 64drive (archived) orders being on permanent hold long before creating this repository.
• EverDrive-64 X7 being disappointment for homebrew development (slow USB upload, unjustified price and overcomplicated SD card access).
• Context: Both aforementioned products were priced at $199 in 2020. 64drive features made it a vastly more useful tool for homebrew development. Since then, 64drive had never been restocked and EverDrive-64 X7 price was lowered to $159 (as of May 2024).
• Jan Goldacker (@jago85) and his projects:
• Brutzelkarte providing solid base for starting this project and sparking hope for true open source N64 flashcarts.
• UltraCIC_C reimplementation for easy integration in modern microcontrollers. Thanks also goes to everyone involved in N64 CIC reverse engineering.
• N64brew Discord server community being very helpful during flashcart development.
• FatFs FAT32/exFAT library being easiest to integrate in embedded environment.
• Yakumono's (@LuigiBlood) extensive 64DD documentation and its implementation in various emulators.
• Libdragon open source N64 SDK project and its developers.
• SERV bit-serial 32-bit RISC-V CPU soft core.