Re: Got IEC code working

From: Marko Mäkelä (
Date: 2004-05-27 10:14:26


> I know 00 is easy, but 00 just shows up so much, In some files, it could
> double the size of the file.

How common is it to load uncompressed files containing many 00 bytes?
The problem is probably biggest with the data files of graphics editors.
However, I don't have anything against the $f2 that you suggested.

> Well, I think some standardization on protocol might be useful.

I agree.  I don't have any other strong preferences other than it should be
possible to implement the protocol on the 2313 in less than 1 kilobyte of
flash ROM, because the protocols for the tape interface occupy about
1 kilobyte, and the total ROM size is 2 kilobytes.

> >It'd be good to draw one diagram without JDos and another including it.
> > 
> That was the plan, but have them as overlays.

That's a good plan.  But please make the serial bus transition diagrams
available first.  The layout may need to be changed radically if errors
need to be corrected.  I think it's better that you produce the diagram
independently, so that you will not be copying my possible mistakes.

> 66 (with my code, not sure on base 64)

If VICE x64 can be trusted, it's 66 there as well.  For the record, it
is 2 when not using true drive emulation.  Better check it with real
hardware.  Can you or someone do that?  Just LOAD"NOSUCHFILE",8 and

> I am getting the impression that EOI is never used when ATN low.

Good.  I think that this was discussed last summer on the list, and
the consensus was that EOI is only used for normal data bytes.

> As stated in another email, I have server code running.  save 
> "/home/brain/incoming/stuff",13 is working

Yep, I got SAVE to work first as well.  It's easy; you'll only be receiving
bytes with and without ATN.  The only tricky part is the EOI handshake.

> Load needs a bit more thought.  It works now (I have a hardcoded app 
> stored on the AVR for testing), but I need some commands to send to the 
> AVR to tell it to wait for data, or not to bother, because file cannot 
> be found.

After talk-attention turn-around, the AVR has become a talker and it
can pause for an arbitrarily long time, until it starts to send, releases
the bus, or the controller drops ATN.


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