In the COMPACT memory model, all function and procedure
variables and local data segments reside in the external data memory
of the 8051 system. This external data memory may be up to 256 bytes
(one page) long. With this model, the short form of addressing the
external data memory through @R0/R1 is used.
Regardless of memory model type, you may declare variables in any
of the 8051 memory ranges. However, placing frequently used variables
(such as loop counters and array indices) in internal data memory
significantly improves system performance.
Note
The stack required for function calls is always placed in
IDATA memory.
This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.
ARM websites use two types of cookie: (1) those that enable the site to function and perform as required; and (2) analytical cookies which anonymously track visitors only while using the site. If you are not happy with this use of these cookies please review our Privacy Policy to learn how they can be disabled. By disabling cookies some features of the site will not work.