disassembly of 6803 code

[Arnaud Westenberg]

Nigel Duckworth wrote:
> 
> Arnaud wrote:
> 
> > I downloaded the data sheet for a MC6803E processor. I assume there will
> > be some differences between the processors but also that they use the
> > same instruction set?
> 
> >From memory the 6803 uses the 6800 instruction set but don't quote me on that,
> it's been a long time since I played with these.

That's what the specs say but I wasn't sure if a MC6803U4CPR (can)
contains additional/specific Ford codes.

> > Where/how do I start to disassemble the code? Would a disassembler be of
> > any good?
> 
> I have no experience of disassemblers but have you thought what you will do
> with
> the code when you get it?

First replace some symbols with the correct signal descriptions and try
to understand how everything works? I guess I would have to understand
the code before I can make any usefull changes to it. Isn't this the
standard procedure to try and find some improvements in the program?

> > This raises another question, how does one map the external memory
> > space? The data sheet confirms the external memory at $00FF-$FFF0 but
> > how to figure out that the timer is at $2000-$2007, for example?
> 
> The address of the timer was chosen by the designer of the electronics, it uses
> a range of addresses decoded in hardware.

So this is like the jumper on a isa card to select its hardware address?
So to determine the peripheral addresses I would have to check the
peripheral specs?

Thanks Arnaud
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