Date   : Tue, 18 Mar 2008 21:40:47 +0100 (GMT)
From   : johan@... (Johan Heuseveldt)
Subject: TUBE chip, accessing 'Parasite' side

Hi,

On Tue 11 Mar, Jonathan Graham Harston wrote:
> > Message-ID: <Marcel-1.53-0309225758-b49xSBG@...>
> Johan Heuseveldt wrote:

> > > Doing a bit more digging around I've found that the most usual
> > > memory layout for a 6809 system is as follows:
> > 
> > In a FLEX version all the device drivers need to be rewritten, taken
> > the TUBE into account. Not sure I'll fancy that. Then there is the issue of
>  
> Just like porting Flex to any platform. You'd have to rewrite all
> the drivers for whatever system you would want to run on the 6809
> copro.

[snip: good example]

Thanks. I can only hope all the translations are of this kind.

When looking around I stumbled into the code JuMP table for the diskdrives.
It has ten entries, and indeed seems to be rather simple, so translation must
be doable.

Some of the technical info surprises me. The sector size is 256 bytes, but
only 252 bytes for data. The other 4 bytes are for system use! Random access
to files isn't so flexible; one byte at the time, but a sector is loaded in
memory. Concepts are a bit different!


> > getting the software in the machine. Does taht need any additional Beeb
> code?
>  
> *LOAD code <language address>

What I meant was the actual software. But loading from Internet prevents at
least all the difficulties to get the software in the first place. No
messing around with floppies, which needs to be read first. There is quite a
lot available on the 'net'.

Anyway, for the moment I'll concentrate on this design first, and actually
building it. The current design is not FLEX compatible anyway, as there is
no appropiate MMU present; intentionaly though. Not sure I like FLEX! :-)
Although much more software is available that can be tried.

One step at the time!


Greetings,
Johan

-- 
Johan Heuseveldt <johan@...              >
  aka  waarland

  The best place is a Riscy place
 
The most incomprehensible thing about the world is...
that it is comprehensible, at least in part. - ALBERT EINSTEIN