Standalone ICU without ROM isn't very interesting, and i made some 16V8 for working with it:

• One bit IO: for 4 back-readable outputs and 3 inputs + oscillator/clock (inverter and non-inverter);
• I2C EEPROM controller: for start and proceed getting program codes from I2C memories to HC595 register clocked by HOLD and counter's MSB, ICU clocked by counter's MSB too, SDA connected via diode.