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YUGOSLAV PC /

 

 

 
 
 
 

GALAKSIJA PLUS /

Galaksija Plus was an improved version of Galaksija, with 256 X 208 monochrome graphics mode, 3 - voice sound based on AY-3-8910 and 48 KB RAM.

The hardware of Galaksija Plus was created by Nenad Dunyich and software by Milan Tadich in 1985. The goal was to enhance original Galaksija while keeping the original goal of keeping things inexpensive and simple for the constructor.

Continuing to use Static RAM in Galaksija Plus would have significantly increased the cost, so designers decided to switch to dynamic, built out of 4416 chips. Larger memory prompted the need for faster cassette tape data recording rate, which was increased to 1200 bit / s by modifying another piece of firmware.

Having enough memory to store the bit map and since Galaksija's own CPU directly drove the video signal, video generation hardware did not have to change significantly. Video generation routine was modified to take the raw video data from the new video memory instead of relying on character set ROMs. Some games for original Galaksija used to do a similar trick, albeit in a limited fashion due to restrictive memory capacity.

The final hardware upgrade was addition of AY-3-8910 sound - generation chip, providing contemporary - standard sound to Galaksija without the need to use tricks such as with the cassette tape port.

Galaksija Plus featured new software additions: Graphic primitives in BASIC language - commands to draw lines, boxes, circles, other graphic primitives as well as drawing text on graphical screen with different font. Additional firmware (ROM C) also featured Full Screen Source Editor and soft scrolling.

 

, 1985 . , .

:

  • C , , ;
  • , 48 ;
  • / 1200 / ;
  • , 256 X 208 ;
  • : 3 - , AY-3-8910;
  • - .

SPECIFICATIONS

  • ROM: additional ROM "C" or "3" - 2 KB (in 2716 EPROM) - additional firmware specific to Galaksija Plus (e.g. graphics mode drivers and handling);
  • RAM: 48 KB of 4416 dynamic RAM, 46 KB accessible;
  • Storage media: cassette tape, recording at either 280 or 1200 bit / s rate;
  • Text mode 32 X 16 characters, monochrome;
  • Graphics mode: 256 X 208;
  • Sound: 3 - channels + white noise provided by AY-3-8910;
  • I / O ports: two 8 - bit parallel ports (e.g. printer and general port).

Galaksija Plus hardware memory map:

  • $0000...$0FFF ROM "A" or "1" 4 KB contains bootstrap, core control and Galaksija BASIC interpreter code;
  • $1000...$1FFF ROM "B" or "2" 4 KB (optional) additional Galaksija BASIC commands, assembler, machine code monitor, etc;
  • $2000...$27FF keyboard and latch;
  • $2800...$2FFF RAM "C": 2 KB ($2800...$2BFF Video RAM);
  • $3000...$37FF RAM "D": 2 KB;
  • $3800...$3FFF RAM "E": 2 KB;
  • $4000...$7FFF RAM IC9, IC10: 16 KB;
  • $8000...$BFFF RAM IC11, IC12: 16 KB;
  • $C000...$DFFF unused, reserved;
  • $E000...$FFFF ROM "3" + "4" IC13: 8 KB Graphic primitives in BASIC language, Full Screen Source Editor and soft scrolling.

:

  • $0000...$0FFF A: 4 , , Galaksija BASIC;
  • $1000...$1FFF B (): 4 - Galaksija BASIC, , ;
  • $2000...$27FF ;
  • $2800...$2FFF C: 2 ($2800...$2BFF );
  • $3000...$37FF D: 2 ;
  • $3800...$3FFF E: 2 ;
  • $4000...$7FFF IC9, IC10: 16 ;
  • $8000...$BFFF IC11, IC12: 16 ;
  • $C000...$DFFF , ;
  • $E000...$FFFF "3" + "4" IC13: 8 BASIC, Full Screen Source Editor .

 

To upgrade to Galaksija Plus you must do the following:

  • to cut the wires marked with a red cross on the upgrade scheme;
  • add new connections are marked with blue dots on the upgrade scheme;
  • connect the wires with the new expansion board.

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  • ;
  • ;
  • .


The 11, 12 and 13 pins of the trigger 74LS74 and the 11, 13 pins of the 74LS38 need to connect under this scheme. Scheme of Galaksija upgrade is presented in figure (scheme cliccabile).

11, 12 13 74LS74 11, 13 / 74LS38 . ( ).

 

 

NEW EXPANSION BOARD /

Scheme of Expansion board is presented in figure (scheme cliccabile). The following is a list of parts used.

( ). .

PCB diagram of Expansion board is presented in figures below (figures cliccabile). The following is the pin assignment of the I / O plug.

( ). .

 

SOUND GENERATOR /

Scheme of Sound generator is presented in figure. The following is a list of parts used.

. .

PCB diagram of Sound generator is presented in figures below. The following is the pin assignment of the I / O plug.

. .

 

GALAKSIJA PLUS CLONE BY PVV / PVV

PVV created a Galaksija Plus clone with SD card controller. PCB designed by Fifan. The schematic file and the file archive for PCB production are presented in the table. The following is a list of IMC used.

PVV SD . Fifan'. . .

PVV made it very simple to start the "Plus" mode. To do this, you need to type on the keyboard: A=USR(&E000) and then GRAPH. To reverse the change of mode, you must reset the computer. The operating system written by PVV allows you to work with an SD card. To go to it you need to type on the keyboard: A=USR(F000) and then DIR. To download the program you need to type its name without extension.

Galaksija Plus from PVV hardware memory map:

  • $0000...$0FFF ROM "A" or "1" 4 KB contains bootstrap, core control and Galaksija BASIC interpreter code;
  • $1000...$1FFF ROM "B" or "2" 4 KB (optional) additional Galaksija BASIC commands, assembler, machine code monitor, etc;
  • $2000...$27FF keyboard and latch;
  • $2800...$BFFF RAM: 30 KB ($2800...$2BFF Video RAM);
  • $C000...$C7FF RAM: 2 KB (SDOS);
  • $C800...$CFFF SD interface;
  • $D000...$DFFF unused, reserved;
  • $E000...$FFFF ROM "3" + "4" IC13: 8 KB Graphic primitives in BASIC language, Full Screen Source Editor and soft scrolling, Plus ROM, SDOS.

 

PVV "". : A=USR(&E000) GRAPH. . , PVV SD . : A=USR(&F000) DIR. .

PVV:

  • $0000...$0FFF A: 4 , , Galaksija BASIC;
  • $1000...$1FFF B (): 4 - Galaksija BASIC, , ;
  • $2000...$27FF ;
  • $2800...$BFFF : 30 ($2800...$2BFF );
  • $C000...$C7FF : 2 , SDOS;
  • $C800...$CFFF SD ;
  • $D000...$DFFF , ;
  • $E000...$FFFF "3" + "4" 8 BASIC (Plus ROM), SDOS.

 

Scheme of Sound generator from PVV is presented in figure. To start the music playback program, you need to type on the keyboard: PTXPLAYER from the PTX directory. See screenshot below.

PVV . : PTXPLAYER PTX. .

 

Scheme of PS/2 keyboard adapter from PVV is presented in figure. The schematic file and the file archive of PIC project are presented in the table.

PS/2 PVV . PIC .

List
File /
Scheme of Galaksija Plus clone from Fifan
Fifan'
Binary file for EPROM 27C64 "CHRGEN" (DD5)
27C64 "CHRGEN" (DD5)
Binary file for EPROM 27C128 "ROM" (DD11)
27C128 "ROM" (DD11)
Gerber files for the production of PCB
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File archive for SD card from PVV
SD PVV
File archive for PS/2 keyboard adapter from PVV
PS/2 PVV
     
     
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