Formulas for Pull Up resistors

[Ericwatson]

What are some basic easy pull up and pull down resistor formulas?

It seems that the equations for pull up and pull down resistor formulas are all different for every logic TTL chips and Cmos chip?

Are they all different or can I use one formula to get the pull up or pull down resistor values?

 

[dick_freebird]

The formula is simple at the heart of it. Variation comes
from the assumptions - what supply, pullup strength,
output drive strength, etc. Besides this there is not a
single right answer, but a continuum of "good enough".