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The PowerPak is a flash cartridge made by RetroUSB. It uses an FPGA to emulate a wide variety of mappers, allowing the user to store a large collection of NES ROMs on a single Compact Flash card and run them on an NES. It is widely used by NES software developers to test their homebrew software.

Product page: http://www.retrousb.com/product_info.php?products_id=34

Mapper Compatibility

The PowerPak mappers have undergone several revisions, gradually improving compatibility. After official development ceased in 2010, Loopy and TheFox have each created a supplemental set of PowerPak mappers to improve its capabilities.

Power Mappers

TheFox created a set of revised PowerPak mappers to supplement or augment the existing ones, most notably adding a savestate feature.

Download: http://kkfos.aspekt.fi/projects/nes/powerpak/powermappers/

Known problems:

  • MMC3 IRQ can cause shaky status bars and similar problems on some systems.

Loopy's Mappers

Loopy released a set of revised PowerPak mappers in 2011, adding fixes and additional support for a several mappers:

Download: https://home.comcast.net/~olimar/NES/powerpak_loopy.zip

Offical Mappers V1.34

The last official release of mappers was in 2010. It supports a wide variety of popular mappers.

Download: http://www.retrousb.com/product_info.php?products_id=34

TODO: list of supported mappers.

Known problems:

  • MMC3 support is insufficient for Low G Man, as the mapper 4 implementation is Startropics-compatible instead of MMC3 accurate. See mapper 4 and MMC6.

Development limitations

Aside from mapper incompatibility, there are minor differences between running NES programs on the PowerPak versus a traditional single-game cartridge.

  • The PowerPak does not accurately simulate power-on state. Because power-on always boots the PowerPak menu, RAM and various registers will be initialized to a consistent state before any NES ROM is chosen to run. (Reset state, howevere, is not affected by this problem.)
  • Open bus behavior may be different in several memory regions that are used by the PowerPak, but would not be connected on a regular cartridge.