µVISION: On-chip ROM Option

Information in this article applies to:

• C166 Version 4.x

SYMPTOMS

What's different when I use the "On-Chip ROM (128k)" option on the Siemens 166CR-16LM? My project gives errors when I'm not using it, but is fine when I check the box.

CAUSE

When the option is checked, µVision automatically allocates your code/const classes to use the range of memory in which that ROM "lives" according to the data sheet. Without it, (and also if you don't have any ROM defined in the external memory) the linker is assuming you have no ROM which will generate problems of locating classes like NCODE.

RESOLUTION

You'll notice that the classes defined with and without the option checked are different. You can check this by clicking the "L166 Locate" tab on the "options for target" dialog.

Last Reviewed: Tuesday, November 17, 2020