What does the 0x80 port address connect to?

Question

When sending a command and reading the data from a certain chip, say the RTC, different documents say that we should wait for some time before reading from the device to make su

Answer 1

You can write (and read) to (from) port 0x80 by using this code in a kernel driver:

(Note that some PCs like mine have a WORD at this location so one can write 16 bits to it.)

Windows driver example:
__outword(0x80, 0x00A0);

This may also be used for kernel debug in cases where you do not have a two machine debug system and you can't use debugview traces for any reason (like the system freezes). Port 80 may be keeping your last debug code for you.