Elektronika MK-52

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production: 1983-1991 Display type: Numeric display  
New price: SUR 115.00   Display color: Green  
    Display technology: Vacuum fluorescent display 
Size: 3"×8"×1½" Display size: 8+2 digits
Weight: 14 oz    
    Entry method: Reverse Polish Notation 
Batteries: 4×"AA" alkaline Advanced functions: Trig Exp 
External power: D2-37 adapter   Memory functions:  
I/O: Expansion ports     
    Programming model: Partially merged keystroke 
Precision: 8 digits Program functions: Jump Cond Subr Ind  
Memories: 15 numbers Program display: Keycode display  
Program memory: 105 program steps and 512 bytes Program editing: Overwrite capability  
Chipset:   Forensic result: 9.0881449  

*EEPROM memory

mk52.jpg (32994 bytes)The MK-52, often described as one of the last Soviet-designed calculator (later models, like the MK-85, are obviously based on Japanese models like those made by Casio) is a uniquely capable device. To the best of my knowledge, this is the only calculator in the world that offers permanent storage in the form of an internal EEPROM module.

Most newer calculators offer permanent storage in the form of non-volatile (CMOS) memory. The contents of program and data memory (and often, even the contents of the calculator's display) are preserved when the unit is turned off. In contrast, programs and data stored on the MK-52 are lost when the calculator is powered down; however, it is possible to copy both programs and data, up to 512 bytes in total, to internal storage.

The calculator also offers two expansion ports. Programs and data in these ports is accessed in a fashion similar to the method used for accessing the internal EEPROM.

The internal EEPROM is organized as 1024 4-bit nibbles. Each program step requires 1 byte (2 nibbles) of memory; each register requires 7 bytes (14 nibbles.) When reading, clearing, or writing the EEPROM, the address and range are specified in the form of a 7-digit number, the first digit of which must be non-zero but is otherwise ignored. Address 1aaaann means nn bytes, starting at nibble address aaaa. The D-P switch controls whether data or program memory is transferred; another three-position switch is used to select read, write, and clear (apparently required before write) operations.

Take, for instance, the Gamma function program (identical to that shown for the MK-61) below. To store the contents of 7 registers (0-6) at EEPROM address 0000, followed immediately by the 84 program steps, you need to perform the following (after entering the program and the constants, of course):

  1. Set the three-position switch to the Clear position.
  2. Enter 1000049 A^ ^v
  3. Enter 1009884 A^ ^v
  4. Set the three-position switch to the Write position.
  5. Set the D-P switch to the Data position.
  6. Enter 1000049 A^ ^v.
  7. Set the D-P switch to the Program position.
  8. Enter 1009884 A^ ^v.

Afterwards, you can recall the data and the program by setting the three-position switch to the Read position, and performing steps 5-8 above.

MK-52 English keyboardTo help those who wish to use the MK-52 but find the Cyrillic labelling incomprehensible, I've created an English version of the calculator's keyboard, shown on the right. I used more or less standard English key labels, and I also reversed the labelling for conditional statements to match standard Western usage.

Reportedly, the MK-52 (equipped with special-purpose ROM modules) was also used in the Russian space program as backup in the case of on-board computer failure.

M0: 2.5066283
M1: 76.180092
M2: 86.505320
M3: 24.014098
M4: 1.2317396
M5: 1.2086510e-3
M6: 5.3952394e-6

00    0E    B^
01    01    1
02    14    <->
03    5C    x<0
04    15    15
05    0E    B^
06    25    \(\circlearrowright\)
07    12    ×
08    25    \(\circlearrowright\)
09    25    \(\circlearrowright\)
10    25    \(\circlearrowright\)
11    01    1
12    10    +
13    51    БП
14    03    03
15    47    x-П 7
16    14    <->
17    48    x-П 8
18    61    П-x 1
19    67    П-x 7
20    01    1
21    10    +
22    13    ÷
23    62    П-x 2
24    67    П-x 7
25    02    2
26    10    +
27    13    ÷
28    11    -
29    63    П-x 3
30    67    П-x 7
31    03    3
32    10    +
33    13    ÷
34    10    +
35    64    П-x 4
36    67    П-x 7
37    04    4
38    10    +
39    13    ÷
40    11    -
41    65    П-x 5
42    67    П-x 7
43    05    5
44    10    +
45    13    ÷
46    10    +
47    66    П-x 6
48    67    П-x 7
49    06    6
50    10    +
51    13    ÷
52    11    -
53    01    1
54    10    +
55    60    П-x 0
56    12    ×
57    67    П-x 7
58    13    ÷
59    18    ln
60    67    П-x 7
61    05    5
62    0-    .
63    05    5
64    10    +
65    18    ln
66    67    П-x 7
67    00    0
68    0-    .
69    05    5
70    10    +
71    12    ×
72    10    +
73    67    П-x 7
74    11    -
75    05    5
76    0-    .
77    05    5
78    11    -
79    16    ex
80    68    П-x 8
81    13    ÷
82    50    C/П
83    52    B/O