Calculator for electronic/firmware engineers

[DA74254]

HP Prime should do the trick.
Built in SI units and all other thinkable units and constants.
HEX/DEC/BIN/OCT calculations and conversions
(Not sure about CRC though)

What's not there, can easily be "installed" or programmed.
There is an electric/engineering library available on this forum in the library/programs section.

Scientific and Engineering notation as well.

Inputs coosable between Algebraic, RPN or Textbook.

Also has a strong built-in CAS