Thomson - MO/TO (Theodore)


Theodore is a Thomson MO/TO system emulator based on Daniel Coulom's DCTO8D/DCTO9P/DCMO5 emulators. Thomson MO/TO is a family of 8-bit home computers produced by French company Thomson SA between 1982 and 1989. At the time of this writing, Theodore emulates the following versions of the MO/TO family: TO8, TO8D, TO9, TO9+, MO5.

The Theodore core has been authored by

  • Thomas Lorblanchès

The Theodore core is licensed under

A summary of the licenses behind RetroArch and its cores have found here.




The Theodore core does not feature BIOS use.


Content that can be loaded by the Theodore core have the following file extensions:

  • .fd (floppy disk)
  • .sap (floppy disk)
  • .k7 (tape)
  • .rom (cartridge)
  • .m7 (cartridge)
  • .m5 (cartridge)


Frontend-level settings or features that the Theodore core respects.

Feature Supported
Netplay -
Core Options
RetroArch Cheats
Native Cheats -
Controls -
Remapping -
Multi-Mouse -
Disk Control
Language -
Crop Overscan -
LEDs -


The Theodore core's internal core name is 'theodore'.

Frontend's System directory

File Description
theodore.cfg Config file

Geometry and timing

  • The Theodore core's base width is 672 pixels.
  • The Theodore core's base height is 432 pixels.


Once the content and core are loaded the start screen is displayed as shown below.

Now it is time to start BASIC 512 that will run the program on the bootable device currently presented. To do that you only have to press the "B" button of your joypad that is conveniently mapped to the "B" key (except for TO9 where the "B" button is mapped to the "D" key to start BASIC 128).


  • BASIC 512 works for a vast majority of games.
  • In case of failure try the 2nd BASIC by pressing "C" key.
  • When using a cartridge, the "B" button is mapped to the "A" key to start the program on the cartridge (entry not shown here).

Core options

The Theodore core has the following option(s) that can be tweaked from the core options menu. The default setting is bolded.

  • Thomson flavor [theodore_rom] (TO8|TO8D|TO9|TO9+|MO5)

  • Floppy write protection [theodore_floppy_write_protect] (disabled|enabled)

  • Tape write protection [theodore_tape_write_protect] (disabled|enabled)

  • Dump printer data to file [theodore_printer_emulation] (disabled|enabled)

User 1 device types

The Theodore core supports the following device type(s) in the controls menu, bolded device types are the default for the specified user(s):

  • None - Input disabled
  • RetroPad - Joypad
  • RetroPad w/ Analog - Joypad

Other devices

  • Light pen - The computer's light pen inputs are mapped to the mouse.


RetroPad Inputs User 1 input descriptors
"Fire" button
Autostart program
(See: Usage)
Virtual keyboard: go up
Virtual keyboard: go down
Virtual keyboard: keystroke

On controllers without Y/X keys, select can also be used to roll the virtual keyboard up. The order of the keys in the virtual keyboard is: digits (0->9) then letters (A->Z) then "Space" then "Enter".


RetroKeyboard Inputs Theodore Inputs
Keyboard Tab STOP
Keyboard Left Control CNT
Keyboard Caps Lock CAPSLOCK
Keyboard Left Alt ACC
Keyboard Home HOME
Keyboard Up UP
Keyboard Down DOWN
Keyboard Right RIGHT
Keyboard Left LEFT
Keyboard Insert INS
Keyboard Delete DEL
Keyboard F1 F1
Keyboard F2 F2
Keyboard F3 F3
Keyboard F4 F4
Keyboard F5 F5
Keyboard Shift + F1 F6
Keyboard Shift + F2 F7
Keyboard Shift + F3 F8
Keyboard Shift + F4 F9
Keyboard Shift + F5 F10


RetroMouse Inputs Theodore Inputs
Mouse Cursor Light pen cursor
Mouse 1 Selection