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 ROMs on a single Compact Flash card and run them on an NES. It is widely used by homebrew NES developers to test their software. It's also compatible with the CopyNES.
Famicom expansion audio is supported, and output on the EXP 6 expansion pin on the cartridge connector. A simple modification to the NES allows the expansion audio to be mixed with its output.
- PRG size: 512 KB (252 KB for NSF)
- CHR size: 512 KB
- Auxiliary PRG-RAM size: 32 KB
Product page: http://www.retrousb.com/product_info.php?products_id=34
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.
The commonly recommended setup is:
- Begin with the Official mapper set.
- Add Loopy's mapper set on top, replacing files.
- Add the PowerMapper set on top if you want savestate support (see its readme).
- Add any of the additional single mappers if needed.
TheFox created a set of revised PowerPak mappers to supplement or augment the existing ones, most notably adding a savestate feature for the mappers it contains, but removing the Game Genie feature.
- NROM (0)
- MMC1 (1)
- UxROM (2)
- CxROM (3)
- MMC3 (4)
- AxROM (7)
- MMC2 (9)
- MMC4 (10)
- ColorDreams (11)
- BxROM (34)
- GxROM (66)
- FME-7 (69, no expansion audio)
- Codemasters (71)
- MMC3/TxSROM (118)
- MMC3/TQROM (119)
- Mapper 4 IRQ is delayed by 2 cycles like RAMBO-1 to work around noise issues with PPU A12. This does not significantly affect most games.
- Mapper 69 does not support the Sunsoft 5B expansion audio used in Gimmick!
Loopy released a set of revised PowerPak mappers in 2011, adding fixes and additional support for several mappers:
- CNROM (3)
- MMC3 (4)
- MMC5 (5, no expansion audio)
- N163 (19)
- VRC4 (21, 23, 25)
- VRC6 (24, 26)
- BxROM (34)
- Sunsoft-5B (69)
- Codemasters (71)
- JY Company (90, partial)
- NSF (no MMC5 audio, no VRC7 audio)
- Mapper 4 IRQ has reliability issues due to PPU A12 noise, causing status bars etc. to jitter up and down on some systems. (A fixed version is available: forum thread.)
- Mapper 3 now supports unlicensed oversize variants (e.g. used by Panesian games).
- Mapper 4 now supports Startropics.
- Mapper 5 does not support the MMC5 expansion audio.
Myask's Mappers (WIP)
Myask made a few mappers not yet covered by others.
- Irem G-101 (032, but Major League hack/submapper not implemented)
- Irem H3001 (065)
- Taito TC0190 (033)
- Note that some mapper 48 roms have been mislabeled as mapper 33.
- Taito TC0690, TC0190+PAL16R4 (048, very buggy)
- Magicseries Corp (107)
- Action 53 mapper (028): forum thread
- GTROM (111): forum thread
- Magic Kid GooGoo (190): forum thread
- UNROM 512 (030): forum post
- SXROM (001): packaged with PR8, but created by bunnyboy
- NES 2.0 Default Expansion Device header incompatibility fix: forum thread
- Nova's Rad PowerPak Menu: forum thread (alternative PowerPak menu)
Offical Mappers V1.35b
The last official release of mappers was in 2010. It supports a wide variety of popular mappers.
- Mapper 2 limited to 256k PRG. (An oversized version exists for 512k PRG: forum thread.)
- Mapper 3 limited to CNROM support, excluding unlicensed oversize variants (e.g. used by Panesian games).
- Mapper 4 does not support Startropics. (See mapper 4 and MMC6.)
- Mapper 5 (MMC5) is incomplete, and fails to run most MMC5 games.
- Mapper 23 (VRC2/4 variants) is listed as buggy.
- Mapper 92 (Jaleco-JF variant) is listed as buggy.
- Mapper 95 (Namcot-3425) is listed as buggy.
- Mapper 96 (Oeka Kids) is listed as buggy.
Software 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, however, 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. (forum post)
- make_sram : a program written in Python to create PowerPak save files for all NES ROMs in a folder or on a CF card
PowerPak development resources
- PowerPak Menu - information about the organization of the PowerPak's operating system.
- Collection of information and photos, source code for menu and loader: http://nespowerpak.com/
- Source code for CNROM example (Xilinx ISE Webpack 9.1): powerpakdev1.zip
- Source code for some of Loopy's mappers (Verilog): powerpak_loopy_src.zip / powerpak_loopy.zip
- Source code for NSF player: powerpak_nsf_src.zip
- Source code for Mapper 190 (Magic Kid GooGoo): forum thread
- Source code for Mapper 111 (GTROM): forum thread