C51: Reserving Memory Accessed With XBYTE and XWORD

Information in this article applies to:

• C51 any Version

QUESTION

I'm using XBYTE and XWORD to access memory directly. How can I reserve the memory so the compiler doesn't locate variables where I have located my memory buffer?

ANSWER

You may declare an xdata array using the _at_ keyword to reserve memory as follows:

unsigned char xdata buffer [100] _at_ 0x8000;

to reserve 100 bytes starting at 8000h. This ensures that the compiler does not locate any other variables at this location.

MORE INFORMATION

• Refer to Absolute Variable Location in the Cx51 User's Guide.

SEE ALSO

• C51: Reserve Memory at Absolute Bank Addresses

Last Reviewed: Thursday, February 25, 2021