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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.
Theodore emulates all the main models of the MO/TO family: TO7, TO7/70, TO8, TO8D, TO9, TO9+, MO5 and MO6.
It also emulates the Olivetti Prodest PC128, a rebranded MO6 for the Italian market.

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 can be 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)

RetroArch database(s) that are associated with the Theodore core:


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

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


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.

When the "Thomson model" core option is set to "Auto" (default value), the core tries to autodetect the Thomson model to emulate based on the name of the content file, and fallback to TO8 mode if it cannot.
The "Start" button of the controller can be used to start the game. The core will then make an "educated guess" to start the game (cf. Theodore's README file for more info about it).

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 model [theodore_rom] (Auto|TO8|TO8D|TO9|TO9+|MO5|MO6|PC128|TO7|TO7/70)

  • Auto run game [theodore_autorun] (disabled|enabled)

  • Virtual keyboard transparency [theodore_vkb_transparency] (0%|10%|20%|30%|40%|50%|60%|70%|80%|90%)

  • 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 / Press key when the virtual keyboard is displayed
Virtual keyboard: move up/down
Virtual keyboard: show/hide
Start program
(See: Usage)

When the virtual keyboard is displayed, the D-pad is used to move the selected key and the B button is used to press the selected key.
Long press the B button for a sticky key.
The virtual keyboard can also be used with a touch screen.
The transparency of the virtual keyboard can be set using the core's "Virtual keyboard transparency" option.


RetroKeyboard Inputs Theodore Inputs
Keyboard Tab STOP
Keyboard Left Control CNT
Keyboard Caps Lock CAPSLOCK
Keyboard Backspace ACC
Keyboard Home HOME
Keyboard Up UP
Keyboard Down DOWN
Keyboard Right RIGHT
Keyboard Left LEFT
Keyboard Insert INS
Keyboard Delete DEL
Keyboard Alt RAZ
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
Keyboard Left Shift Shift or Yellow key (MO5)
Keyboard Right Shift Shift or BASIC key (MO5)


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

Last update: 2024-05-17