Galaksija Plus
Encyclopedia
Galaksija Plus was an improved version of Galaksija
, with 256x208 monochrome
graphics mode, 3-voice sound based on AY-3-8910 and 48 KiB RAM
.
The hardware of Galaksija Plus was created by Nenad Dunjić and software by Milan Tadić 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 (see original Galaksija
).
Galaksija Plus was manufactured by Institute for School Books and Teaching Aids for an announced price of 140,000 dinars
.
Galaksija
The Galaksija was originally a build-it-yourself computer designed by Voja Antonić. It was featured in the special edition Računari u vašoj kući of a popular eponymous science magazine, published late December 1983 in Belgrade, Yugoslavia...
, with 256x208 monochrome
Monochrome
Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white...
graphics mode, 3-voice sound based on AY-3-8910 and 48 KiB RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
.
The hardware of Galaksija Plus was created by Nenad Dunjić and software by Milan Tadić in 1985. The goal was to enhance original Galaksija
Galaksija
The Galaksija was originally a build-it-yourself computer designed by Voja Antonić. It was featured in the special edition Računari u vašoj kući of a popular eponymous science magazine, published late December 1983 in Belgrade, Yugoslavia...
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
Dynamic random access memory
Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1...
, built out of 4416 chips. Larger memory prompted the need for faster cassette tape data recording rate, which was increased to 1200 bit/s
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
by modifying another piece of firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
.
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
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
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 (see original Galaksija
Galaksija
The Galaksija was originally a build-it-yourself computer designed by Voja Antonić. It was featured in the special edition Računari u vašoj kući of a popular eponymous science magazine, published late December 1983 in Belgrade, Yugoslavia...
).
Galaksija Plus was manufactured by Institute for School Books and Teaching Aids for an announced price of 140,000 dinars
Yugoslav dinar
The dinar was the currency of the three Yugoslav states: the Kingdom of Yugoslavia , the Socialist Federal Republic of Yugoslavia and the Federal Republic of Yugoslavia between 1918 and 2003. The dinar was subdivided into 100 para...
.
Specifications
- CPUCentral processing unitThe central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
: ZiLOGZilogZilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...
Z80A 3.072 MHz - ROMsRead-only memoryRead-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
:- Original ROM "A" or "1" - 4 KBKilobyteThe kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
(in 2764 EPROMEPROMAn EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
together with ROM "B") contains bootstrap, core control and Galaksija BASICGalaksija BASICGalaksija BASIC was the BASIC interpreter of the Galaksija build-it-yourself home computer from Yugoslavia. While being partially based on code taken from TRS-80 Level 1 BASIC, which the creator believed to have been a Microsoft BASIC, the extensive modifications of Galaksija BASIC—such as to...
interpreter code - Original ROM "B" or "2" - 4 KB (in 2764 EPROMEPROMAn EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
together with ROM "A") - additional Galaksija BASICGalaksija BASICGalaksija BASIC was the BASIC interpreter of the Galaksija build-it-yourself home computer from Yugoslavia. While being partially based on code taken from TRS-80 Level 1 BASIC, which the creator believed to have been a Microsoft BASIC, the extensive modifications of Galaksija BASIC—such as to...
commands, assembler, Machine code monitorMachine code monitorA machine code monitor is software built into or separately available for various computers, allowing the user to enter commands to view and change memory locations on the machine, with options to load and save memory contents from/to secondary storage.Machine code monitors became something of a...
, etc. - Additional ROM "C" or "3" - 2 KB (in 2716 EPROMEPROMAn EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
) - additional firmware specific to Galaksija Plus (e.g. graphics mode drivers and handling) - Character ROM - 2 KB (2716 EPROMEPROMAn EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
) contains character definitions
- Original ROM "A" or "1" - 4 KB
- RAM: 48 KB of 4416 static RAM, 46 KB accessible
- Text modeText modeText mode is a kind of computer display mode in which the content of the screen is internally represented in terms of characters rather than individual pixels. Typically, the screen consists of a uniform rectangular grid of character cells, each of which contains one of the characters of a...
32 x 16 characters, monochromeMonochromeMonochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white... - Graphics mode: 256x208
- SoundSoundSound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
: 3-channels + white noise provided by AY-3-8912. - Storage media: cassette tape, recording at either 280 or 1200 bit/sBit rateIn telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
rate - I/O ports: 44-pin Edge connectorEdge connectorAn edge connector is the portion of a printed circuit board consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a single discrete female connector , and they also tend to be...
with Z80 Bus, tape (DIN connectorDIN connectorA DIN connector is a connector that was originally standardized by the , the German national standards organization. There are DIN standards for a large number of different connectors, therefore the term "DIN connector" alone does not unambiguously identify any particular type of connector unless...
), monochrome video out (PALPALPAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
timings, DIN connectorDIN connectorA DIN connector is a connector that was originally standardized by the , the German national standards organization. There are DIN standards for a large number of different connectors, therefore the term "DIN connector" alone does not unambiguously identify any particular type of connector unless...
), UHFUltra high frequencyUltra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...
TV out (RCA connectorRCA connectorAn RCA connector, sometimes called a phono connector or cinch connector, is a type of electrical connector commonly used to carry audio and video signals...
) and two 8-bit parallel portParallel portA parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...
s (e.g. printer and general port)