Discrete logic video games are the earliest video games , the equipment of which did not use microprocessors and control programs and was executed on discrete logic, that is, on digital microcircuits of low degree of integration. Video games of this type appeared in the late 1960s and were released until the mid-1970s.
Device
The main difference from subsequent generations of video game devices, including modern ones, was the lack of a microprocessor, control program, and other elements of a specialized microcomputer in the device. Instead, the devices were a state machine made on a large number of separate logic circuits, usually TTL , of the 7400 series . All the functionality of the game was tightly defined by the electronic circuit. Any change in the graphics or gameplay required a change in the circuit of the device. Games based on discrete logic had very simple graphics and gameplay, since the complexity of these components led to a complication and increase in the electronic circuit, and therefore to an increase in cost.
Discrete logic video games were usually made in the form of an arcade gaming machine , since the large number of electronic components used led to the high cost of such devices. Nevertheless, there were home options, in particular amateur radio designs (usually simpler compared to arcade options).
History
The most famous discrete logic video game is the arcade version of Pong . She was released in 1972. The electronic circuit consisted of 66 microcircuits.
The development of games based on discrete logic involved companies such as Atari , Sega , Taito and Midway, and several others. In total, more than a hundred different slot machines were released. Before the advent of accessible microprocessors, circuits of television gaming devices on discrete logic were published in various amateur radio magazines.
Subsequently, the development of electronics made it possible to release home versions of some video games of this generation, due to the integration of discrete logic into one LSI . These were mainly Pong games and its variants, less often some others. These devices have become the first generation of home gaming systems .
In the USSR, several arcade slot machines based on discrete logic were released - Highway, Interceptor, Gorodki and Safari. Schemes of home television games were published in the journal Radio in the late 1970s and early 1980s. In 1985, the book Amateur Television Games was published (Radio and Communications Publishing House), reprinted in 1989. In addition, before the creation of the IMS K145IK17 , the USSR produced the Palera-02 home game console for 27 IMSs of the K155 series [1] [2] .
Graphics
The common clock generator formed the reference frequency (pixel-clock) and synchronization signals to form a television raster. Graphic elements were formed in separate parts of the circuit based on the reference frequency. Since complex images were required to obtain complex images, the elements were usually vertical or horizontal stripes or separate rectangles. So, the playing field in Pong consists of an empty raster (background), a dashed vertical line, two rectangles and a square (racket and ball).
More complex graphics, such as characters or images of characters (a car in races, an airplane in a scroll-shooter ), could be formed using ROM . In this case, the image forming circuit formed an address in the ROM, and the output level was immediately converted into a video signal. An unusual solution was used to display the current account in the Pong game - the image of the numbers was formed from rectangles, the visibility of which was determined by the decoder chip for the seven-segment indicator (converting the binary code from the counters into seven output signals for controlling the indicator).
Emulation
Since video games on discrete logic are not computer systems, their software emulation is not possible using the standard approach. However, it is possible to simulate the operation of an electronic circuit of a device in the same way as it is done in modern electronic circuit design packages. The video game scheme, taken from the documentation or obtained by the reverse engineering method, is programmatically described as a list of electronic components and their connections. The simulator program calculates the state of the electronic circuit at any given time using the circuit description. In January 2008, the first version of the DICE emulator [3] was published using a similar approach. Three games are currently supported - Pong , Rebound, and Gotcha . The emulator is designed with the simple addition of other games. Software simulation of electronic circuitry requires significant computing resources. DICE’s author suggests that real-time emulation requires a processor with a frequency of 3-4 gigahertz .
Sources
Links
- Discrete Logistics - information, descriptions, photos