What are the advantages in useing xdata memory? Why would you use it? How do you use it?
What are the advantages in useing xdata memory?
It can have a much larger size (up to 64 kB) than the internal memory (which is limited to 256 bytes at most).
Why would you use it?
Because you need more than 256 bytes of RAM.
How do you use it?
You use a memory model that uses xdata memory by default (the lazy way) or manually put variables/arrays/structures into xdata memory by using the xdata keyword.
or more, with a suitable "banking" scheme.
Also, maybe (some of) the variants with "extended" addressing allow >64K XDATA...?
For chips with an external bus interface, you can also use XDATA for memory-mapped IO (MMIO)
or more, with a suitable "banking" scheme. while you are right, I would phrase it "or more, with a suitable mapping scheme" to avoid any misconception that "banking" in the Keil parlance always is the way to go. I, for my huge flashes use 'paging' which is far more efficient (at least for serial access)
Erik