Level converter question

Other Hardware General Electronics
4

There's two questions I have in this level converter topic:

  1. High -> Low

Depending on how fast you are running your SPI communications, a simple potential divider will do the trick.

Do real resistors behave so bad, compared to ideal resistors without any frequency dependency, and compared to diodes I see usually as level converter recommendation ???

  1. Low -> High , if I do not want to rely on the assumption that 3V is high enough to be a logic HIGH in the 5V area ( KirAsh4's issue )
    Do I need some IC doing the level shift, or minimally 2 transistors to get it non-inverting, or is there another electronics trick to "amplify" a 0...3V signal I'm not aware of ???