C51: Support of Non-standard Chip Features

Information in this article applies to:

• C51 All Versions

QUESTION

Are non-standard features in various 8051-compatible devices supported in C, assembly, or both?

ANSWER

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.

MORE INFORMATION

• Refer to Language Extensions in the Cx51 User's Guide.

SEE ALSO

• C51: Creating CPU Header Files
• µVision: Adding Custom Parts to the Device Database

Last Reviewed: Thursday, February 25, 2021