Click Here to visit our Sponsor
The Latest News ! The History of Computing The Magazine Forums Collectors corner Have Fun there ! Buy books and goodies
  Click here to loginLogin Click here to print the pagePrinter ViewClick here to send a link to this page to a friendTell a FriendTell us what you think about this pageRate this PageMistake ? You have mr info ? Click here !Add Info     Search     Click here use the advanced search engine

NCR

Decision
Mate
V
Browse console museumBrowse pong museum









 

www.old-computers.com logo goodies !

see details
Space Invaders - Retro Gamer goodies !

see details
1kb memory only...sorry goodies !

see details
Horace is not dead goodies !

see details
Back to the roots goodies !

see details
Odyssey 2 / Videopac Select Game prompt goodies !

see details
Amiga Workbench goodies !

see details
Odyssey 2 / Videopac sprites goodies !

see details
Amstrad CPC-464 goodies !

see details
Destroy all humanoids ! goodies !

see details
Camputers Lynx logo goodies !

see details
READY prompt goodies !

see details
Commodore 64 goodies !

see details
Oric Atmos goodies !

see details
MZ-700 goodies !

see details
Commodore VIC-20 goodies !

see details
Atari ST bee icon goodies !

see details
Pixel adventurer goodies !

see details
ZX Spectrum goodies !

see details
Apple II goodies !

see details
Commodore 64 boot screen goodies !

see details
Space Invaders goodies !

see details
H.E.R.O. goodies !

see details
I love my Oric-1 goodies !

see details
MSX Retro Gamer goodies !

see details
Atari ST bomb icons goodies !

see details







D > DIDAKTIK > Gama     


Didaktik
Gama

This was a Slovak Spectrum clone made by Didaktik Skalica Ltd. in communism times (1987). It offered 80 KB RAM.

As all Z80A based computers, it was not possible to address more than 64k. So the Gama computers used a bank switching technique, with two 32k additional RAMs. There was even a LED on the case, which indicated if the RAM have been switched or not!

The Gama computers had a built-in paralel i8255 interface. They used the original Ferranti ULA and had russian made memory chips.

The Gama computers were not fully compatible with the original Sinclair Spectrum due to some system variables differences.

In fact several models were made.

- The first one was black and, as it was made in 1987, it is often called Gama'87. It had a bank switching bug : if you switched the banks and the RAMTOP variable was above 32768, then the computer simply crashed...

- In 1988, the Gama'88 was launched (grey case). It's main difference is that the bank switching bug was repaired.

- One year later, the Gama'89 (guess why) was released because the '88 model was still quite buggy. Some bugs in ROM were corrected and hardware was a little bit changed, so the compatibility was improved. It has only latin character set and a print routine was implemented in ROM. The Gama'99 was the last and the best model of the Gama serie, it was manufactured up to 1992.

_______________________

Branislav Bekes sent us info and specs for the Gama'89 :
CPU Z80A, ROM 16k, RAM 80k bankswitched, graphic mode 256x192 with 8 colors, text mode 32x24. Two bottom lines were reserved for interpreter. Sound 1bit beeper.
I/O ports : TV OUT, VIDEO OUT, TAPE IN/OUT shared with POWER SUPPLY connector. Expansion slot and 8255 interface. Power supply is external and offers +5V and +12V.


About the Ram switching, Abraham add:
The memory banks switching in GAMA was used for "tricks", like enabling on GAMA the AY sounds and music in games designed originally for ZX 128, taking game screenshots, enhancing the copy programs and many more things.

ShareThis


 

Hello Damian, it is 5V and 12V, not 24V.

          
Friday 13rd December 2013
Martin

Didaktik gamm power supply is +5v and +24v

          
Friday 22nd June 2012
Damian

Hello, I still have this cool machine and now I am working on a connection with a PC for sending a picture from Didaktik & showing it in a window on the PC. Nice time to U all!

          
Wednesday 5th November 2003
Petr (Czech Republic)

 

NAME  Gama
MANUFACTURER  Didaktik
TYPE  Home Computer
ORIGIN  Slovakia
YEAR  1987
END OF PRODUCTION  Unknown
BUILT IN LANGUAGE  Spectrum BASIC interpreter
KEYBOARD  Full-stroke keyboard, Sinclair style, 40 keys, reset button
CPU  Z80A
SPEED  Unknown
RAM  80 KB (16 KB + 2 x 32 KB)
ROM  16 KB
TEXT MODES  32 columns x 24 lines
GRAPHIC MODES  256 x 192 dots
COLOrsc  8
SOUND  Beeper (1 voice, 5 octaves)
SIZE / WEIGHT  27 (W) x 16.5 (D) x 3.6 (H) cm
I/O PORTS  i8255 interface, expansion bus, TV and monitor output, tape-recorder sockets
BUILT IN MEDIA  None
POWER SUPPLY  External PSU
PRICE   6000,- Kcs (Kès) (1987, Czechoslovakia)


Click here to view our goodies based on ZX Spectrum Click here to view our goodies based on ZX Spectrum

Click here to view our goodies based on Horace is not dead Click here to view our goodies based on Horace is not dead

Click here to view our goodies based on H.E.R.O. Click here to view our goodies based on H.E.R.O.




Google
 
Web www.old-computersc.com


 

More pictures
Hardware Info
Internet Links
Documentations
Mini-Forum

Click here to go to the top of the page   
Contact us | members | about old-computers.com | donate old-systems | FAQ
OLD-COMPUTERS.COM is hosted by - NYI (New York Internet) -