Sam Powell wrote:
>
> Whats the deal with the 256byte memory segments.. They are not page
> boundries are they? i.e. why does it matter if i have a data table crossing
> its boundy?

To access a table data you must modify the PCL register.

ie movf offset,w
   addwf pcl
   retlw datavalue

By modifying the PCL register the PC change is limited to 8 bits, hence
the 256 byte pages.

In this scenario the page concept becomes very important, and the PCLATH
register needs to be set accordingly.

> Also... since 11 bits is enough to address 2K, why does one have to mess
> with the PCLATH register when do inter-segment goto's /calls.

You don't wiith the F84.

--
Best regards

Tony

Multimedia 16F84 Beginners PIC Tools.
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