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ADuC842 - Is the EWAIT  SFR  really existing?

Question asked by Alexandergb on Mar 30, 2012
Latest reply on Apr 5, 2012 by Alexandergb

Hi, gentleman!


The manual for ADuC841-2-3  mentioned the  EWAIT  SFR:


" External Memory Access


There is no support for external program memory access on the

parts. When accessing external RAM, the EWAIT register may

need to be programmed to give extra machine cycles to MOVX

commands. This is to account for differing external RAM access




SFR Address                             9FH

Power-On Default                       00H

Bit Addressable                         No


This special function register (SFR) is programmed with the

number of wait states for a MOVX instruction. This value can

range from 0H to 7H. "


But really when I tried to write a number to the SFR with address 09FH, the programs stops working.

By the way, this SFR is absent in the SFRs table.


Is this register really exist?