Re: 10x CLOAD (fwd)
Date: 1999-10-09 07:21:48

Hallo Marko,

> > Could anybody explain me shortly two things:
> > 1) Is the data send to the recorder the same as the real data to be saved?
> In principle yes, I think.  I haven't played much with the tape, but I
> think that -FLAG is an edge-sensitive input, while the processor line you
> use to control WRITE is level-sensitive.
> > 2) How is the data translated to "music"?
> The data is stored as a square wave (okay, it is more sinusoidal, but an
> op-amp and a cutter in the read circuitry of the datassette make it look
> like a square wave again).

I understand the part of translating a sinus to square; that is purely an 
electronic thing. 

Let's ask a simple question: 1) how are the bytes $FF and $00 put on tape?

The thing I can add is that with the KIM a byte is split up in two nibbles. 
Then each nibble is translated to a character ranging from ??? to ???. Each bit 
of these bytes is translated in a two series of sinuswaves of two different 
frequencies. The length of each of the two blocks determines differs for bit 0 
or 1.


I cannot give more detailed info as I cannot get to it. If you look at the time 
the mail is generated (05.15), I writing during some pauses. Somebody messed up 
things at work and I was phoned out of bed to clear it up :( 

I can imagine that with the PET they skipped the splitting of the byte but 
translating a bit to a bit pattern still must nescesary. 

Groetjes, Ruud


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