Frael Bruc 100
This page was last modified 09:06, 13 April 2019 by Rderooy. Based on work by Gdx and Mars2000you.




This hidden MSX1 was produced by Frael and released in 1987 in Italy, where it was used in secondary schools. It was sold with an extended keyboard including a keypad, a separate data recorder and several educational software on 7 cassette tapes. The power supply is built-in.

There are two models that are identical on the front side. The first model has no cartridge slot but a extension bus.

The Basic of Bruc 100 is not the MSX-BASIC but it is very similar, it's the MCL extended Basic v1.1 or v1.2 (an hacked MSX-BASIC?). The machine is compatible with MSX1 with some little differences or additional features : blinking cursor, step forward word by word, cut a text line, no display of the functions keys, different default color for the Basic screen, etc.

It does not seem that applications were released on disk for this machine, but it was planned. After the two versions of this hidden MSX, Frael has switched to the PC world, still with educational applications.

Brand Frael (Franchi Electronics)
Type Bruc 100
Year 1987 (first model), 1988 (second model)
Region Italy
Original price
RAM 64kB in slot 3 (version 1) or in slot 1 (version 2)
Media MSX Cartridges (version 2 only), Cassette tapes (non-standard?)
Video TMS9129NL
Audio PSG (AY-3-8910)
Chipset none (separate IC's)
Extras Extended keyboard with keypad, separate data recorder with educational software on tapes


There are several versions of the firmware, which has the priority when booting: the first versions display only the Frael logo while version 1.3 gives access to a menu screen where you can choose between BASIC and DIDATTICA. The second option allows to load educational applications from tape or disk, after another intro screen.

As version 2 has a cartridge slot, you can play MSX games released on cartridge. However, you will need to wait for the end of the animation with the Frael logo (with version 1.2 of the firmware), or to select BASIC in the menu (with version 1.3 of the firmware) before to see the launching of the game.



Frael Bruc 100
Frael Bruc 100 computer + tapes
Frael Bruc 100 One of the 7 educational tapes
Frael Bruc 100 Manuals
Frael Bruc 100 Computer Courses
Frael-Bruc 100 back (version 1)
Frael Bruc 100 PCB (version 1)
Frael Bruc 100 PCB (version 2)
Frael Bruc 100 left side
Frael Bruc 100 label
Frael Bruc 100 back (version 2)


Frael Bruc 100 - Frael logo
Frael Bruc 100 - Menu
Frael Bruc 100- Didattica intro


The Bruc 100 is not totally an MSX1 computer. The cartridge slot (or an extension bus without sound input) and the cassette tape connector are a bit different.

This computer doesn't support the FM-Pac nor some floppy disk controllers, etc because the cartridge slot does not provide + 12V nor -12V. It has also the particularity of two /SLTSL signals (pin 4 for slot 2 and reserved pin 16 for slot 3 in version 2). The cassette port is not 100% MSX compatible, the middle pin (GND) is missing.

The Z80A comes from SGS (Z8400AB1). The internal ROMS are the Main-Rom of 32KB (BIOS & MCL extended Basic v1.1 or v1.2) and a specific Rom of 8KB (v.1.0 to v.1.2 - only bootlogo) or 32KB (v.1.3 bootlogo + menu). Both these two roms are in the same slot 0, with a special system of selection that is switchable.

Curiously, the machine works without the bootlogo (+ menu) ROM, because the Main BIOS checks for its presence. If it's not there, it just skips the logo and the eventual menu.

The specific ROM is selected by the bit7 of the I/O port 90h. This is the same port that has the strobe bit (bit-1) in normal MSX computers. Besides the extra bit, the rest of the printer port seems to be pretty ordinary.

Bit7=0: Select Frael MainBIOS ROM on slot 0
Bit7=1: Select the bootlogo+firmware ROM on slot 0

Slot Map of Bruc 100 version 1 with firmware 1.0 or 1.1

Help needed
The below slot-map is an assumption, it needs to be checked on a real machine.
Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh Expansion
Bus Slot
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
switchable with
bootlogo ROM
Page 0000h~3FFFh
  • The bootlogo ROM is a 8kB ROM - 0000h-1FFFh, which is mirrored to 2000H-3FFFh

Slot Map of Bruc 100 version 2 with firmware 1.2 or 1.3

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh 64kB
Slot (EX-Box)
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
switchable with
firmware ROM
Page 0000h~3FFFh
  • Firmware 1.2 : the bootlogo ROM is a 8kB ROM - 0000h-1FFFh, which is mirrored to 2000H-3FFFh
  • Firmware 1.3: the bootlogo + menu ROM is a 32kB ROM - 0000h-7FFFh
  • The unique cartridge slot can be doubled, just like for the Mitsubishi ML-TS2



The keyboard on the unit is a bit different from a MSX. There are 107 keys including a number pad, shortcut keys and some mirror keys. Here are the key codes of the extra keys:

Word-> : Line-9, column-7 
Word<- : Line-9, column-6 
CUT LINE : Line-9, column-5 
END LINE : Line-10, column-0 

The diagonal keys just produce the keycodes of both two keys they represent, as if the two keys were pressed at the same time.

The keyboard layout is international, except for the numpad. Those are the keys that differ from the standard numpad:

-  : Line-9, column-1
(  : Column-7 repeated on lines 10, 11, 14 and 15
)  : Column-7 repeated on lines 10, 11, 14 and 15
+  : Line-9, column-0 
<  : Column-5 repeated on lines 10, 11, 14 and 15
>  : Column-4 repeated on lines 10, 11, 14 and 15
*  : Line-9, column-2
/  : Line-9, column-3

All other keys of the numpad that weren't listed above are "fakes", which means that they in fact produce the same keycodes as their respective keys in the normal keyboard. Just like the Gradiente Expert models do for their numpad.