Calculator for electronic/firmware engineers

[kuro68k]

I've been looking for a calculator for use in electronic and firmware engineering for ages. I'm thinking of features like:

- SI unit support, including input
- Decent hexadecimal support
- Binary/hex/decimal conversion with editor
- CRC calculation
- Built in formulas for common circuits

Some Casio models have two ENG buttons for going up or down x1000, but don't use SI notation. It gets to be a bit of a chore constantly doing e10,9,sign over and over. The CG-20 and a few other models let you assign SI units to the function keys and enter them with one press, and also display SI units on screen.

Were there ever any calculators designed for engineers like me?