C51: SUPPORT OF NON-STANDARD CHIP FEATURES
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Are non-standard features in various 8051-compatible devices supported in C, assembly, or both?
Both. Most chip-specific features are implemented through the addition of special function registers (SFRs). C header files, included for the most commonly used processor derivatives, define the SFRs for that derivative.
It is easy to create your own header files for new chips. In most cases, using the extended features of these chips is as simple as adding a single line of code to this header file. For example, the following line of code declares the SFR for the 8051's port 1:
sfr P1 = 0x90;
Adding register definitions is almost identical in assembly language.
Last Reviewed: Friday, July 15, 2005
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