Recently I have got a nice add-on for my Elektronika MK-52 calculator. I’s an Elektronika BRP-3 module. The BRP means “memory extension block” but really it is a read-only memory which is filled with 60 mathematical programmes. It is an interesting and relatively rare thing, anyway. There are informations around the Internet that only 17000 of the BRP-3 were produced.
There are other BRP-x packages with for different purposes (at least 4 types exist, one of them contains flight-related computations for Soyuz-TM spacecraft – the Elektronika MK-52 with this module was used as a backup flight computer).
The BRP-3 contains programmes for much more common tasks. The available programmes can be used to solve various small mathematical problems which are common in engineering or science. There are programmes for solution of systems of 2 or 3 linear equations, computation of determinants and other matrix operations, solution of differential equations,solution of non-linear equations, numerical integration and other tasks of similar complexity. It may sound mostly useless today, and it probably is, but when the MK-52 was new then it was the only affordable (or even the only available) programmable personal computer for many Soviet engineers and scientists. So in that time such module was useful for its users.
Practical use is both straightforward and uneasy. It has to be attached to the extension slot of the MK-52. The rest is identical to use of internal pernament memory (the EEPROM). There is a switch on the BRP-3 which is used to indicate what memory is used (internal/external). Actually, there are two switches. The BRP-3 is divided into two parts so the second one is used to select the active part.
For an use of the module one has to load the selected programme to the RAM by specifying its address (the proper number can be found in the printed manual) and by pressing of two keys (“address selection” and “program loading”) and also fill the calculator variables with input data). The problem is that there is obviously no indication what to do (or where find results) and the paper manual must be consulted. Without the manual one has to load the program to the RAM and print it to the display (only numerical codes of the operations are shown so some experience is necessary) and then to understand what the program does and what it requires.