Hardware - loading programs into the Spectrum from a CD using SP-Dif.

 Development of the idea              
 ---------------             
                                        
You are writing about the Axis on the Spectrum. me
this idea has always interested me VERY MUCH.
There are some of our own developments (about this
some other time). In general, pre-
I’m guessing (so that it doesn’t have to be completed)
turn Spectrum) do this:          
                                        
 1) In the form of an audio track (as if from
tape recorder) the bootloader is loaded (from the CD).
It contains a driver for loading from CD
in digital form by SP-Dif (also audio
track, but in the form of direct digitization / see.
note 1/).                               
                                        
 2) Next, SPDifloads BIOS. And he
is already loading the actual OSas is
which it is convenient for the user.               
                                        
 __note__1____                      
                                        
 Audio track format (in principle, not
specifically): 44100*4 kbytes/sec:         
16 bit left channel,                      
16 bit right channel,                      
16 bit left channel,                      
16 bit right channel                      
......                                  
                                        
 SPDif connector: 1-GND, 2-SPDOut;       
By SPDif - data flows sequentially,
through channels. More accurate information for me
promised to give it in “solid form” within
weeks.                                 
                                        
 Tofirstly, to avoid confusion -
left/right, and also provide
noise immunity (protection from damage)
media) I suggest recording in
track sequentially in 2 samples (2 ka-
nala by 2 bytes per sample total 2*2*2=
8 bytes) same byte of data, then
by downloading eight bytes and cpahub them, we
we can almost always restore the data
nye). It won't affect the speed much.
(150k bytes/sec divide by 8 will be approx.
lo 20k per second, which is for Spectrumall
equally the speed is awesome). And we're semi-
tea drive CD-ROM for Spectrum,without
improvements to the last one!                   
                                        
 - - -                  
                                        
 For now, I'm figuring out SPDif'and pi-
I have a driver on my pussy, so I wanted to
I would still like to find out how they will react to
this idea the rest of the readers, and where everyone
connect SPDif. Personally, I suggest
printer port for three reasons - y some-
which already have it (me for example ;),
it has all the necessary signals and except
in addition, if per port (device)
the printer, the CD-ROM and, by the way, hang up
there is a lot more... you can do it artificially
connection, and install ir23 and tm2 +de-
1Bh port encoder (if there is interest in
this material, I will send the diagram to the following
number):                             
                                        
 connection:              
 --------------             
                                        
BDO >-----> Stop/eject to CD buttons 
BD1>----->Play/next/ROM drive. BUSY <----< SDPdif to SPDif dis-  
GND <-----> GND / him.            
                                        
 However, there are other options:     
 ---------------------------------   
                                        
 for example:                          
 1) Make a special port. (but this is otnyr-
there aren't many).                            
 2) Use tape output,
and, for example, a joystick.                  
 3) By flashing the BIOS, place-
create a subroutine loading into ROM (fortunately,
pzyCh8 there are about 200-300 bytes unoccupied
tykh) and use tape input and
output, and (as in option 2)
goes between magicians  output and CD-ROM
install a small device, convert-
converter of 2 consecutive bits into two
control signal.  Just the third va-
riant will save us from the need to gru-
Install the bootloader in the standard way.    
                                        
 If the ideawould be of interest, in my opinion,
 3) By flashing the BIOS, place-
create a subroutine loading into ROM (fortunately,
pzyCh8 there are about 200-300 bytes unoccupied
tykh) and use tape input and
output, and (as in option 2)
goes between magicians  output and CD-ROM
install a small device, convert-
converter of 2 consecutive bits into two
control signal.  Just the third va-
riant will save us from the need to gru-
Install the bootloader in the standard way.    
                                        
 If the idea is of interest, then, in my opinion,
the best carrier for the OS (and without
I can’t find any special improvements to the computer.       
                                        
 In addition, as soon as (and if) you select
pem port, I will post the complete circuits and
description of how to connect with options for
various CD drives.  And also the driver
bootloader.