LPT AY by Vitaly Mayatskih                   2:5002/11.4@fidonet
         & Alexander Kulik [Wolf^eTc/Scene]   2:4635/8.18@fidonet
------------------------------------------------------------------------------------------------ 

     user's manual by Wolf^eTc/Scene
 
 Contents:
 
     0. Introduction;
     1. How to connect AY to LPT port of PC ( scheme );
     2. How to programm AY thru LPT port;
     3. Software support ( plug-in for emulator by Shalaev );
 

 0. Introduction
 
     Several days ago  in  the ZX.Spectrum FIDO area  appeared  messages about
connection AY sound chip to LPT port of your PC. I was very interested by this
scheme and even unsubscribed from area to have some time to finish our project
and find my own way to  connect AY to LPT port of PC. Some time later I've re-
ceived  message from Vitaly Mayatskih with ready to use scheme. After checking
this scheme out I did some changes in "Select" signal realisation. In the very
first version that  signal was attached to 13 pin of the port, but I connected
it  to 17 pin  because old  "Select" ( pin 13 ) work in input  mode only. Also 
were added two resistors and one capacitor instead of one resistor :).
     In same day I built this little board, connected to PC and  wrote plug-in
for Zx-Spectrum emulator by Shalaev.
     Believe or not but most hardest thing in building  this board was finding
one spare AY sound chip :)
 

     1. AY to LPT scheme;
 
        ZQ1                   +5v
 +------|||------+             16    Ê555IE10/Ê1533IE10
 | +---+   +---+ |        +----------+
 |1|1  O2-3|1  O4+------2-/ C|    |4 |12---+
 | +---+ | +---+ |   +--1-O R|    |  |     |
 +--|||-----|||--+   |    |--|    |  |     |
    R1      R2       |--3-|D0|    |  |     |
                     |--4-|D1|    |  |     |
    155LN1           |--5-|D2|    |  |     |
                     |--6-|D3|    |  |     |
                     |    |--|    |  |     |
                     |--7-|V1|    |  |     |
                     |--9-|V2|    |  |     |
                     |    |--|    |  |     |
                     |-10-OPE|    |  |     |
                     |    +----------+     |
                     |         8           |
                   +5â        ---          |
                                           |
                                -Init(16)<+|
                               +5v        ||
                               40         ||
                           +----------+   ||
            Select(17)<-29-|B1|    |RSO-23+|   AY-8910
                   +5v<-28-|B2|    |FC|-22-+
                           |--|    |--|
                |2------37-|D0|    |A8|-24-|
              L |3------36-|D1|    |A9|-25->+5v        ---
                |4------35-|D2|    |BD|-27->-Strobe(1)  |
              P |5------34-|D3|    |  |    R3           | R7+  C1
                |6------33-|D4|    |--|   +|||---------------||--> LEFT
              T |7------32-|D5|    |A |4--+    | R5
                |8------31-|D6|    |B |3-------|
                |9------30-|D7|    |C |38-+    | R6         +  C2
                           +----------+   +|||---------------||--> RIGHT
                                1          R4           | R8
                               ---                      |
                                                       ---
 
ZQ1 - 14MHz; R1,R2 - 470; R3,R4,R5,R6,R7,R8 - 2kOm; C1,C2 - 10mkf*5v
 
     IC 555LN1 used to build 14MHz generator. 1533IE10 used to build frequency
divider.
 
     Here is a pin table  on case you want use AY-3-8912 instead of AY-3-8910:
 
 +--------------------------+
 |      |AY-3-8912|AY-3-8910|
 |------+---------+---------|
 |RES   |  16     |    23   |
 |CLK   |  15     |    22   |
 |D0-D7 |  28-21  |    37-30|
 |BDIR  |  18     |    27   |
 |BC1   |  20     |    29   |
 |BC2   |  19     |    28   |
 |CS1   |  17     |    25   |
 |CS0   |  none   |    24   |
 |A     |  5      |    4    |
 |B     |  4      |    3    |
 |C     |  1      |    38   |
 |+E    |  3      |    40   |
 +--------------------------+
 
     2. How to programm AY thru LPT port;
 
     The AY chip is accessable thru two ports - 0x0378 and 0x037A. The 0x0378 
is data port and 0x037A is control port.
 
     I believe not many words needed to describe programming:
 
     Sound chip initialisation:
 
    procedure resetAY;
     begin
           port[$37a]:=0;
     end;
 
     Sound chip registers programming:
 
    procedure AY(reg,data:byte);
     begin
           port[$378]:=reg;
           port[$37a]:=12;
           port[$378]:=data;
           port[$37a]:=4;
 
     end;
 
     reg - AY internal register number (0-13);
     data - internal register value;
 
     In this example is shown how to select AY  sound chip internal  register:
 
     port[$378]:=reg; port[$37a]:=12;
 
     In this  example is shown  how to  load necessary  value to AY sound chip
internal register ( register number should be set with previous example ):
 
     port[$378]:=data; port[$37a]:=4;
 
     3. Software support ( plug-in for emulator by Shalaev )
 
     As mentioned above I've written plug-in  for Zx-Spectrum emulator made by
Shalaev. Currently  this is the 1.0 version, but in case you want something to
add or you even found a bug please feel free to mail me to my FIDO address:
2:4635/8.18 To Wolf^eTc/Scene.
     For a current moment I am going to do the mosr boring thing - write an
WinAmp plug-in to support this scheme and write good player for DOS. This
player will support any file formats and will have ability to use different
kind of plug-in modules.
 
 \/\
 
                                                Wolf of eTc/Scene