KR1806VE1 -  Rarest USSR Soviet Russian 4-bit low power NMOS MCU (Angstrem plant, 1994)

Great item for chip collectors !!!

The microcircuit is a 4-bit microcontroller (OEVM) without ROM.
The command system includes 6 conditional jump commands with 7 execution conditions each;
17 unaddressed commands; 5 instructions of operations, each having 7 modes of addressing to operands;
6 instructions for operations with pairs of registers; 5 commands for operations with constants.
Instructions for indirect access to RAM (8 to x 4) can be addressed by two pairs of registers.
An indirect ROM reading command has been implemented, which makes it possible to carry out multiplication and division operations.

The IC works with an external ROM (8 to x8) of the K573RF4 type, and also requires hardware support in the form of an 8-bit address register. Number of commands - 39.

The number of 4-bit I/O ports is 4, the number of 4-bit registers is 4, the number of 8-bit registers is 4, the organization of the built-in RAM is (80 x 4) bits,
the maximum capacity of external RAM is (8192x4) bits, the maximum capacity external ROM - (8192x8) bits,
bit length of the timer-event counter - 8, stack depth - 3 levels, maximum speed 100,000 instructions / sec.
Internal input/output ports are bidirectional, any bit can be programmed to input or output information.
Body type 2204.42-3.

Electrical parameters
Supply voltage ...............................................4.5. ..5.5 V
Consumption current:
at /=30 kHz ............................................... ......<0.1mA
at /=1 MHz .............................................. ........<1 mA
Clock frequency ............................................'... 32 kHz...1 MHz

Look an actual pictures - You receive exactly what You see!!!

IC from the old stock, like new, in working order.