PowerPak Menu: Difference between revisions

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The PowerPak boot ROM and menu system use its own simple mapper. The PowerPak menu is split into a series of modules that reside at $0400-$07FF in the NES's built-in RAM and are loaded from the CF card. After booting, the module "I.MAP" is loaded and run.
The PowerPak boot ROM and menu system use its own simple mapper. The PowerPak menu is split into a series of modules that reside at $0400-$07FF in the NES's built-in RAM and are loaded from the CF card. After booting, the module "I.MAP" is loaded and run.
== Modules ==
Modules are switched between by writing the filename to fileEntry (usually a single character, calling ClearFindEntry beforehand if it's not already cleared), then calling CardLoadModule. Source for all modules is located [http://nespowerpak.com/powerpaksrc/ here].
* '''A.MAP''' (<u>A</u>to) - checks a "saves" directory for a save with the same name as the ROM being loaded
* '''B.MAP''' (<u>B</u>attery) - save selection screen
* '''D.MAP''' (<u>D</u>isk?) - FDS save selection screen
* '''E.MAP''' (<u>E</u>rror) - displays "Bad File Header"
* '''F.MAP''' (<u>F</u>DS) - attempts to load an "FDSBIOS.BIN" from the PowerPak directory into WRAM, then starts an FDS game
* '''G.MAP''' (<u>G</u>ame Genie) - Game Genie .txt file selection screen
* '''I.MAP''' (<u>I</u>nitial?) - title screen
* '''L.MAP''' (<u>L</u>ast) - saves the game name to LASTNES.TXT in the PowerPak directory
* '''M.MAP''' (<u>M</u>usic) - loads an NSF and the NSF player, and starts the NSF
* '''N.MAP''' (?) - ROM selection screen
* '''O.MAP''' (<u>O</u>ptions) - game options screen, with Game Genie code entering and save loading
* '''Q.MAP''' (<u>Q</q>uestion) - "save to CF card?" screen
* '''S.MAP''' (<u>s</s>ave) - writes a save to the CF card


== Banks ==
== Banks ==

Revision as of 05:10, 10 July 2017

The PowerPak boot ROM and menu system use its own simple mapper. The PowerPak menu is split into a series of modules that reside at $0400-$07FF in the NES's built-in RAM and are loaded from the CF card. After booting, the module "I.MAP" is loaded and run.

Modules

Modules are switched between by writing the filename to fileEntry (usually a single character, calling ClearFindEntry beforehand if it's not already cleared), then calling CardLoadModule. Source for all modules is located here.

  • A.MAP (Ato) - checks a "saves" directory for a save with the same name as the ROM being loaded
  • B.MAP (Battery) - save selection screen
  • D.MAP (Disk?) - FDS save selection screen
  • E.MAP (Error) - displays "Bad File Header"
  • F.MAP (FDS) - attempts to load an "FDSBIOS.BIN" from the PowerPak directory into WRAM, then starts an FDS game
  • G.MAP (Game Genie) - Game Genie .txt file selection screen
  • I.MAP (Initial?) - title screen
  • L.MAP (Last) - saves the game name to LASTNES.TXT in the PowerPak directory
  • M.MAP (Music) - loads an NSF and the NSF player, and starts the NSF
  • N.MAP (?) - ROM selection screen
  • O.MAP (Options) - game options screen, with Game Genie code entering and save loading
  • Q.MAP (Question) - "save to CF card?" screen
  • S.MAP (save) - writes a save to the CF card

Banks

  • PPU $0000-$1FFF: 8 KB switchable CHR RAM bank.
  • CPU $6000-$7FFF: 8 KB switchable PRG RAM bank, selects from the 512 KB "PRG ROM" space.
  • CPU $8000-$BFFF: 16 KB switchable PRG ROM bank, selects from boot ROM.
  • CPU $C000-$FFFF: 16 KB PRG ROM bank, fixed to the last bank of boot ROM.

Registers

FPGADATA ($5000)

The boot ROM writes $FF to this register. It tells the FPGA it is being reprogrammed.

FPGAPROGRAM ($5800)

7  bit  0
---- ----
DDDD DDDD
|||| ||||
++++-++++- Writes a byte of configuration to the FPGA.

MAPPERWR ($8000)

7  bit  0
---- ----
.... ..DD
       ||
       ++- Selects the bank of boot ROM that appears at $8000-$BFFF.

Banks 0, 1 and 2 contain the initial FPGA configuration. Bank 3 contains 8KB of font and then 8KB of system routines. As the last 16KB are also accessible via the fixed bank, the $8000-$BFFF area isn't useful for menu software.

PRGBANK ($4200)

7  bit  0
---- ----
WCDD DDDD
|||| ||||
||++-++++- Selects the bank of PRG RAM that appears in $6000-$7FFF.
|+-------- Enable CHR RAM writing if 1.
+--------- Selects from 32KB of WRAM instead of main PRG RAM.

CHRBANK ($4201)

7  bit  0
---- ----
..DD DDDD
  || ||||
  ++-++++- Selects the bank of CHR RAM used.