ULA1 (also known as ULA-1, ULA-216, T34VG1, KA1515HM1-216) -
Ultra RARE USSR Russian Clone (+ some features) of ULA Video controller for ZX-Spectrum .
Used in ZX-Spectrum 48k/128k(Sinclair Research LTD edition of Didaktik Game)
Computers together with Z80 (Z80A) Zilog CPU.
This ULA1 Chip - the replacing about 15 digital ICs of standard logic + original ULA from Didaktik Skalica.

This is a completely original LSI, embedded with some proprietary solutions.
For example, video memory, separate and with its own controller in
English and Slovak (Didaktik Game) computers,
was schematically combined with a common RAM with a single controller.
The RAM used dynamic memory required by periodic regeneration.
This process is similar to the process of regenerating the image on the screen, and they were combined in one device.
 
Example of ZX-Spectrum computer on this ULA see on the last photo in the auction
 
Made in 1990, Angstrem plant, OP (Opytniy) - development (pilot) batch
 

Great item for chip collectors !!!

Some history about Z80

Development of Zilog Z80 microprocessor was based on Intel 8080/8085 series, 
therefore Z80 is backward 8085 compatible by command set and machine code, 
it can execute any programs written for 8085. 
For example, CP/M-80 OS can be run on 8080, 8085, Z80. 
But forward compatibility is not always achieved, mainly because of additional commands, 
registers, and other new features that are present in Z80.

As 8080/8085 processors, Z80 was manufactured in 40-pin dual inline package. 
There are modifications that differ by clock frequency. 
Address lines, in contrast to 8085 are not multiplexed, 
so the number of management lines and types of interrupts is reduced. Interrupts can be masked and non-masked.

Command set of Z80 is compatible with 8085, though command mnemonics are different. 
There are additional commands for block transfer, checking/setting of separate operand bits, 
working with packed binary-decimal code, organising cycles, performing relative transitions.

Z80 microprocessor does not have clock generator as 8085 does and needs an external chip to do this. 
Having only one input for masked interrupt requests it causes all devices connected to processor to form one priority chain. 
All support chips released by Zilog are called "Z80 - chip type", for example Z80-PIO, Z80-UART and others. 
 
This processor was used in Tandy Radio Shack TRS-80 PC. TRS-80 computer, created by Steven Leyninger, 
was sold together with monitor, keyboard, tape recorder, and tapes that contained CP/M-80 OS and additional software. 
In September 1977 the computer hit the market and had sales of 10 thousand a month during the whole next year. 
Later, selling a computer assembled and with all needed components preincluded became essential.