LARM: USING ON-CHIP AND OFF-CHIP FLASH ON PHILIPS ARM

Information in this article applies to:

• CARM Version 2.0 or higher

QUESTION

I have configured the Philips device for startup in off-chip memory, but I am also using the on-chip Flash ROM. If I set "Use on chip flash" the LARM Linker/Locater gets the following CODE memory class:

CODE(0x0000-0x3FFFF)

However, the 0x40 bytes are paged into the external Flash and the location 0x0 - 0x40 is effectively not available.

Is there a way to overcome this problem?

ANSWER

Your analysis is correct. When starting a program from off-chip memory on a Philips LPC22xx target, the on-chip Flash in the memory region 0 - 0x3F becomes useless.

To solve this problem, enter under Project - Options - LA Locate:

Reserve: 0 - 0x3F

The LARM Linker/Locater will then no longer use the address space between 0 and 0x3F.

MORE INFORMATION

• Refer to RESERVE in the LARM User's Guide.

Last Reviewed: Friday, July 15, 2005