circuit A4350

[oldcomp]

Does anyone have information on how the A4350 calculator circuit is connected? It is said to have been cloned by the Soviets and used in their calculators.

[JPLRMD]

The A4350 circuit was manufactured by Rockwell. It was imported to Eastern Europe through the Polish company Unitra. Tesla Bratislava used this circuit in OKU104 calculators. I drew the wiring diagram of the OKU104 and OKU107 calculators in 2015 and you can download them from the website http://www.jplabs.co.uk/cz/cs_doc.html.
I do not know the Soviet version of this circuit, nor have I ever encountered it.

[oldcomp]

I have several OKU calculators, but none of them work. They mostly have non-functioning buttons or broken wires to the keyboard board. I don't know where to reconnect the wires. So I thought of soldering the calculator circuit, making a new board and improving the calculator, adding memory and making it programmable using classic circuits. I was surprised by the power supply of the calculator. What exactly is the level of log.0 and log. 1 ?

[borec]

that interests me: How can a calculator circuit that can perform 4 basic operations be turned into a programmable calculator? Using a microcomputer? It makes no sense with a microcomputer if the microcomputer itself replaces the calculator circuit. I can't imagine this expansion without a microcomputer with classic circuits.

[JPLRMD]

What exactly is the level of log.0 and log. 1 ?

The logic levels of the A4350 circuit are inverse compared to log. levels for the CMOS-4000 line circuit.

[oldcomp]

so if i understand correctly i can use CMOS 4000 series for A4350 circuit?

[JPLRMD]

yes, but you have to adjust the logic levels. As far as expansion is concerned, rather than making the A4350 circuit into a programmable calculator, it is more appropriate to use additional logic to extend the functions. The A4350 circuit has only 4 basic functions.