From GameBrew

Last Updated2008/10/26

PSP7800 is an Atari 7800 ProSystem emulator for the Sony PSP from Ludovic Jacomme (aka Zx-81).

It is based on ProSystem Emulator v1.1, an Atari 7800 emulator for the PC and Windows OS, made by Greg Stanton.


Unzip the ZIP file, and copy the content of the directory to ms0:/PSP/GAME/.

Put your roms files on roms sub-directory.

If you want to use the original 7800 Bios, then put the file called 7800.rom in the /PSP/GAME/psp7800/ directory.

User guide

Load Rom files (A78)

Put your rom file (with .zip or .a78 file extension) on your PSP Memory Stick in the roms directory, and go to Load ROM from the emulator main menu.

You can use the virtual keyboard in the file requester menu to choose the first letter of the game you search (if you have tons of games in the same folder).

Use the Run key of the virtual keyboard to launch the rom.

Cheat Code (CHT)

You can use/add your own cheat codes in the cheat.txt file and then import them in the Cheat menu.

Using the Cheat menu you can search for modified bytes in RAM between current time and the last time you saved the RAM (monitoring values for example life numbers).

All cheat codes you have specified for a game can be save in a CHT file inside cht folder. For example,

# Enable, Address, Value, Comment
1,36f,3,Cheat comment

Those cheat codes would then be automatically loaded when you start the game.


  • Sound enable.
  • Display fps.
  • Speed limiter.
  • Skip frame.
  • Render mode.
  • Delta Y.
  • Vsync.
  • Swap Analog/Cursor.
  • Active Joystick.
  • Auto fire period.
  • Auto fire mode.
  • Display LR led.
  • Clock frequency.

Key mappings

You can toggle between three different mappings in the emulator window (Standard, L-Trigger and R-Trigger mappings).

Not all games however can be played with the default keyboard mappings, you can write your own mapping file (KBD) to overcome the issue (follow the syntax from the sample files default.kbd in the kbd directory).

You can save/load and edit your own KBD files in Keyboard menu; and if the keyboard filename is the same as the rom file (A78) then when you load this rom file, the corresponding keyboard file will be automatically loaded.

Virtual keyboards

You can use the Danzeff On-Screen Keyboard (by Danzel and Jeff Chen) and IR keyboard for entering letters, special characters and digits.

Edit the pspirkeyb.ini file to specify your IR keyboard model, and modify eventually layout keyboard files in the keymap directory.


Atari 7800 (Standard):

Cross - Fire1

Square - Fire2

Triangle - L Diff

Circle - R Diff

D-Pad - Up/Down/Left/Right

Analog - Joystick

Atari 7800 (L-Trigger):

Square - Hotkey FPS

Triangle - Hotkey Load state

Circle - Swap D-Pad/Analog

Cross - SAVE Snapshot

Up - Inc delta Y

Down - Dec delta Y

Left - Render mode

Right - Render mode

Atari 7800 (R-Trigger):

Square - Pause

Triangle - Reset

Cross - Auto-fire

Circle - Select

Up/Down - Up/Down

Left - Dec Fire

Right - Inc Fire

Analog - Joystick

All mappings:

Start+L+R - Exit and return to XMB

Select - Enter emulator main menu

Start - Open/close the On-Screen keyboard

Main menu:

R - Reset the emulator

Triangle - Go Up directory

Cross/Circle - Valid

Square - Go Back to the emulator window

On-Screen Keyboard:

Analog - Choose one of the 9 squares

Triangle/Square/Cross/Circle - Choose one of the 4 letters of the highlighted square

L/R - See other 9 squares figures

IR Keyboard:

D-Pad - Cursor

Start - Tab, Ctrl-W

Select - Escape, Ctrl-Q

Triangle - Ctrl-E

Cross - Ctrl-X

Square - Ctrl-S

Circle - Ctrl-F

L - Ctrl-Z

R - Ctrl-C





Developed for Firmware 5.01-M33.



  • Improve global emulation speed.
  • New render modes.
  • Add vertical shift feature.
  • Finally fix issue with "Home -> Exit".
  • Add documentation for settings in help menu.
  • The virtual keyboard is now usable in the file requester menu to choose the first letter of the game you search.
  • Improve file requester with virtual keyboard to choose sequentially rom files beginning with a given letter.
  • Text editor to write your own comments on games.
  • Display first comment line while browsing game files.
  • Cheat support.
  • Memory monitoring engine to find your own cheat code.
  • Text editor to modify the global cheat.txt file.
  • Zip rom files are now decompressed in memory (much faster).
  • Add option to disable auto fire in settings menu.
  • Add eboot music (see
  • Source code can now be compiled to build a linux version.


  • Sound improvement & NTSC Palette fix by Carpy (aka Danno).
  • A thumbnail image is now displayed in the file requester while selecting any file with the same name of a previously saved game. It might be very helpful to recognize that game later if you have thousand different games in your rom folder.
  • Auto-fire uses now the key mapped as Cross button instead of FIRE1 (games such as Xevious use FIRE2 for fire so it is better this way).
  • In the emulator menu you can go directly to keyboard and settings menu using the L-Trigger key.
  • Fix IR keyboard issue with fw >= 3.80 for FAT PSP.
  • Fix random black screen issue.
  • Bug fix in the low battery watchdog.


  • Major speed improvements (> 60 fps at 222Mhz) but limited at 50fps by default.
  • Auto-fire mode, press RTrigger+X to switch it on/off useful for games such as space Xevious. On given games, the auto fire can't be stopped easily (so you might have to disable it several times).
  • It uses now only PSP GU for rendering.
  • IR keyboard support.
  • Add several new hotkeys:
    • Settings such as fps, render mode, auto fire speed can now be directly modified inside the emulator (no need to enter in the settings menu).
    • Quick save / quick load current state (no need to enter in the main menu).
  • RTrigger/LTrigger keys can be used in the keyboard settings menu to navigate between Normal, LTrigger and RTrigger compose mapping.
  • Analog pad can be used in the rom file requester.
  • Default Hotkeys can now be set in the keyboard mapping menu (useful to add hotkeys on existing/previous keyboard files).
  • Bug fix in the low battery watchdog.


  • Sound engine back to previous version.


  • Display and save thumbnail images for each save state.
  • IR keyboard support (mainly for menu).
  • Add option to display fps rate.
  • Option to prevent the blue led to be displayed when L or R are pressed.
  • Add option to display fps rate.
  • New PSP clock option (it can now run at 133 Mhz).
  • New speed limiter function.
  • New sound engine (always crappy but faster).
  • Import code from ProSystem version 1.2.


  • Compatible with custom firmwares 3.x and PSP-slim.
  • Add a simple intro splash screen.
  • Support iso8859-1 fonts in print text functions (might be useful to translate psp2600 menus in german, french).
  • Bug fix in file requester.


  • Bug fix in sound.
  • Bug fix in image display.


  • Merge diff from ProSystem v1.2.
  • Add option to display frame rate.
  • Improve speed.
  • New speed limiter function.
  • New background image.
  • Bug fix in file requester.


  • New graphical functions with new smoother render modes. It uses the PSP GPU for rendering, it does not run faster, but it's a lot smoother.
  • Add a new fullscreen option (render mode max).
  • Rom selector support now .rom and .bin as valid file extention.
  • Save state dates are displayed in the emulator window (it's now easier to identify and to load the right save state slot).
  • Multiple keyboard mapping feature (Thanks to Pou-chan):
    • You can now toggle between three differents keyboard mapping using LTrigger and RTrigger keys.
  • Bug fix in Rom file requester.


  • The two following features were presents in the original ProSystem emulator but had been disabled during the PSP port:
    • Add bios file support (you need the 7800.rom file).
    • Add games database system (prosystem.dat file).
  • Load default.kbd file on startup (if file is present in kbd folder).


  • Bug fix : All roms (such as BallBlazer) that used the Pokey audio chip made the emulator to crash.
  • New icons from Gelon.


  • Add Sound support.
  • Add Render modes (Normal, x1.25, x1.5).
  • Add Frame skip option.
  • Add new speed limiter option.
  • Fix colors palette (merge the code from ProSystem v1.1).
  • Code cleaning.


  • Intial release.


  • PSP7800 is a port on PSP of the version v1.1 of ProSystem.
  • Danno aka Carpy for the help on game compatibility issues, sound code and NTSC color palette.
  • Thanks to Gelon for the eboot icons and to all PSPSDK developers.
  • Eboot music written by NeXuS.

External links