ARM Technical Support Knowledge Articles

USING PDATA MEMORY

Applies to: C51 C Compiler

Answer


Information in this article applies to:


QUESTION

I'm using a chip with on-chip XDATA memory. I want to use one 256-byte page as PDATA. How do I do that?

Does the upper address byte come from P2?

ANSWER

Accessing a 256-byte page (PDATA) of on-chip XDATA is possible and often desirable since PDATA is more efficient than XDATA.

When On-chip XDATA is Enabled...

To configure the tools for PDATA access, you must...

When On-chip XDATA is Disabled...

Most 8051 devices use the value of Port 2 as the upper address byte for PDATA accesses. With such a configuration, the required startup code settings are nearly identical to the above except that the PPAGE SFR must be specified as PPAGE_SFR DATA 0A0H.

MORE INFORMATION

SEE ALSO

Article last edited on: 2007-01-04 08:12:32

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