Environment Settings

If you run the Cx51 Compiler within µVision IDE, you do not need any additional settings on your computer. If you want to run the Cx51 Compiler and utilities from the command prompt, you must manually create the following environment variables.

Variable	Path	Description
PATH	\KEIL\C51\BIN	Path to the C51 and CX51 executable programs.
TMP		Path to use for temporary files generated by the compiler. If the specified path does not exist, the compiler generates an error and aborts compilation.
C51INC	\KEIL\C51\INC	Path to the folder for Cx51 include files.
C51LIB	\KEIL\C51\LIB	Path to the folder for Cx51 library files.

For Windows NT, Windows 2000, Windows XP, and Windows 2003, environment variables are entered under Control Panel — System — Advanced — Environment Variables.

For Windows 95, Windows 98, and Windows ME, the settings are placed in AUTOEXEC.BAT using the following commands:

PATH=C:\KEIL\C51\BIN;%PATH%
SET TMP=D:\TMP
SET C51INC=C:\KEIL\C51\INC
SET C51LIB=C:\KEIL\C51\LIB