Programming - procedure for channel indicators on "AY" (equalizer).

                                          
                                          
          'AY' CHANNEL INDICATORS         
          -----------------------         
                                          
   Various in-
 music channel volume indicators
 processor. I will give an example of indicators,
 which you could see for example in the main
 menu of the first issue 'RT'.                
                                          
                                          
 SPEST LD A,8;channel A          
       LD НL,#4800 ;screen address     
       CALL DYNA                          
       LD A,9; channel B          
       LD NL,#4801                      
       CALL DYNA                          
       LD A,10;channel C          
       LD NL,#4802                      
       CALL DYNA                          
       RET                                
 DYNA LD ВС,#FFFD ;Query the port  
       OUT (C),A ;music processor    
       IN A, (C) ; and take the value 
       АND 15 ;channel volume 
       OR 1 ;at the moment. 
       LD V, A ;Display 
 DYN1 LD A,%01111110 ;bar, display 
       LD (HL), A ;pressure level   
       CALL UP ;volume        
DJNZ DYN1                          
       RET                                
 UР DEC N; looking for the address on    
       LD A,H ;pixel above      
       AND 7 ;available       
       SR 7                             
       RET NZ                            
       LD A,L                           
       SUВ 32                            
       LD L,A                           
       RET C                             
       LD A,H                           
       АDD А,8                           
       LD H,A                           
       RET                                
                                          
                                          
   That's it! Everything ingenious is simple! Try
 do it yourself and don’t forget to wash the old stuff
 image from the screen before displaying the new
 go, otherwise three will appear on your screen
 motionless stripes and that's all the law -
 reads.  Well, I say goodbye to you until next time...
 current issue of the magazine and look forward to letters from you
 questions and suggestions. And if someone
 wants to publish his programs, then
 no problem! Send it!