Programmers - a scheme for blocking incomplete ports.

 SpellBbinder present           
                                         
 REVOLUTION on Speccy !!!        
                                         
     May the readers forgive me for this
loud name, but the idea of this development
tka is somewhat extraordinary.                
     Now let's get serious. Not for anyone
cret that additional ports on the computer
rah besides the advantages (additional para-
crumple, disable ROM, etc.) bring
users and headaches, namely non-
the need to block them.  Otherwise
In this case, some programs and demos do not work.
The proposed schemes to combat this conclude
are in hard decryption of port data and
are a useful addition to the com-
pewter, however, do not solve the problem
ness. When accessing ports via shortcut
addressing problems still arise.   
addressing still has problems.   
For example: LD A,#DF                       
 OUT (#FD),A  - the port will work
at PROFI (#DFFD). An even sadder situation
ation on SCORPIO:         
 STS 3.3 does this                       
 LD A,#1F                       
 OUT (#FD),A                     
he of course wants to turn on the 7th bank, but
Ironically (or the creators of SCORPIE-
SHE) port #1FFD and the computer respond
hangs safely.                    
 I’m not even talking about PENTAGON-512.      
                                          
 So, comrades, this is over now!
The proposed scheme "tracks" commands
short addressing and blocks for a while
its execution, all critical ports. What
allows you not to use the block buttons -
port routing.                             
 DD2                     
 ┌---┐ ┌- +5V            
D0 °-------------┤ │ │                 
D1 °-------------┤ & │ │ ┌-┬--┐         
 ┌--┐DD1 │ │ •--┤S│ │ _____
D2 °----┤1 °--•--┤ │ └--┤R│ Q├---°BLOK 
        └--┘ └--┤ │ ├-┤ │         
D4 °------------┤ °-----┤D│ _°         
 ┌--┐DD1 │ │ ┌--┤C│ Q│         
D5 °----┤1 °-----┤ │ │ └-┴--┘         
 └--┘ │ │ │ DDЗ           
D6 °-------------┤ │ │                 
D7 °-------------┤ │ │ DD1-15ЗЗЛН1     
__ └---┘ │ DD2-15ЗЗЛA2     
M1 °--------------------┘ DDЗ-1533TM2     
                                         
   The scheme works simply:            
 There are only two short addressing commands:     
these are  IN A,(NN) - #DB and  OUT (NN),A - #D3.
They differ in just one bit - D3,
We just don’t start it. When appearing on
data bus byte #DB or #D3 at output
LN2 will appear logical 0. If this byte
LN2 a logical 0 will appear. If this byte
the code of the operation extracted by the processor, then
signal M1 will fix it in TM2 until next
blowingopcode retrieval cycle.
If the processor considers any other instruction
Yes, then logical 1 will be recorded in TM2.
This signal (BLOK) is used to block
kupobku critical ports. And the same for
control the decryption rigidity of others
ports (for example #7FFD and music coprocessor)
allowing you to have hard decryption when
long addressing and simplified for short addressing
coy.       
       
     This scheme has been tested on a computer.
PROS and SCORPIO and showed beautiful
results. For questions related to this
using the new scheme, contact me through the editor-
tion of the magazine.                              
                                          
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