It causes problem. I have to rename the one in C:\silabs\MCU\INC to other name in order to solve the problem.

I feel that the need to turn off that optino manually is troublesome. I have more than 400 students using the tool. If it can be transparent, it would be great.

Wondering why ver 4.01 added this as default. The need to remove this flag every time starting a project is very troublesome.

Also wondering if the header files there could be compiler independent. Notice that there is "c8051f330_defs.h" which would require one to also include "compiler_defs.h".

Why not make "c8051f330.h" same as "c8051f330_defs.h" but with an additional line of "include " at its top to save user to need to do it.

Ops, realize that "c8051f330_defs.h" did not define TI, RI, SBUF but only TI0, RI0, SBUF0 ... My lab experiment uses only TI ... Also realize that "c8051f330_defs.h" has a bit of conflict with the library I give to students as the library was built using "c8051f330h" supplied with SDCC.

I feel that the IDE should not default to have -I"C:\SiLabs\MCU\Inc" in the compiler option. Instead users can always copy necessary files from there when need arises.

My current solution now is to ask students to rename the file in C:\SiLabs\MCU\Inc to a different name like c8051f330orig.h so that things become transparent again.

I suppose the -I"C:\SiLabs\MCU\Inc" was added to ensure that all newer MCUs header files are picked up.

The linking problem I encountered was due to a error in SDCC header file:
__sbit __at (0xCD) TF2CEN ; /* TMR2CN.5 - TIMER 2 LOW-FREQ OSC CAPTURE ENABLE*/
should be
__sbit __at (0xCC) TF2CEN ; /* TMR2CN.4 - TIMER 2 LOW-FREQ OSC CAPTURE ENABLE*/

This conflicts with the correct definition in "c8051f330_defs.h"
Once changed, there is no problem mixing the use of SDCC "c8051f330.h" and files compiled using
#include
#include

There is an improvement when one creates a new MCU specific C project project.

Older IDE copies c8051f330.h that is Keil C specific to the project folder causing serious problem with SDCC. We had to tell students NOT TO CREATE MCU specific C project to overcome the problem. The new IDE copies only c8051f330_defs.h. It is now "safe" to have "include " with SDCC. However, -I"C:\SiLabs\MCU\Inc" bring back the same problem as it now picks up Keil C specific c8051f330.h from Silab INC folder!

Another problem: We use config wizard a lot. The codes generated has "#include ". The new IDE environment with -I"C:\SiLabs\MCU\Inc" causes it to pickup Keil C header file again !

My conclusion is that the c8051f330.h should contain only these:
// c8051f330.h
// This header file works for different compilers
#include
#include

..config wizard .. codes .. has "#include "..

.. c8051f330.h should contain only these:
// ..compilers
#include
#include

..config wizard .. codes .. has "#include "..

.. c8051f330.h should contain only these:
// ..compilers
#include
#include

..config wizard .. codes .. has "#include c8051f330.h"..

.. c8051f330.h should contain only these:
#include compiler_defs.h
#include c8051f330_defs.h