Acorn Electron Plus One: Disabling the Centronics and A/D Port
Applicable Hardware: Acorn Electron
Support Group: Acorn Computers Limited, Acorn House, Vision Park, Histon,
Cambridge CB4 4AE

Related Application Notes:

Copyright (C) Acorn Computers Limited 1992 Every effort has been made to
ensure that the information in this leaflet is true and correct at the
time of printing. However, the  products described in this leaflet are
subject to continuous development and improvements and Acorn Computers
Limited reserves the right to change its specifications at any time. Acorn
Computers Limited cannot accept liability for any loss or damage arising
from t he use of any information or particulars in this leaflet. ACORN,
ECONET and ARCHIMEDES are trademarks of Acorn Computers Limited.

6th July 1992
Support Group Application Note Number: 013
Issue: 1
Author: 

We have received a number of enquiries regarding the Plus One with other
software houses products, which make use of some of the locations reserved
in the operating system.  Such software usually works on the Acorn
Electron alone, but not with the Plus One fitted.  Issuing the command *FX
163,128,1 as described in the User Guide may be sufficient to enable the
software to be used; if not the following code will remove the Plus One
completely from the address map disabling the Centronics and A/D ports
(additionally disabling the RS423 cartridge if fitted). Pressing <BREAK>
will return the Electron to its normal state.  The routine can be saved on
cassette/disc and CHAINed prior to loading the required program.

10  *FX 163,128,1
20  A%=&AA : X%=0 : Y%=&FF
30  !&80=USR&FFF4 : A%=!&81
40  A%?12=0

NB:  This routine will not operate across the Tube.

26th July 1992 Support Group Application Note No. 013, Issue 1
Support Group Application Note No. 013, Issue 1