Re: A1200 Busboard survey! (was Re: CVision3d & A1200T)

[Ignatios Souvatzis <ignatios%theory.cs.uni-bonn.de@localhost>]

Hi Ruben,
> > 
> > E.g., I heard that some early zbus-boards dont include bus sizing
> > logic, which makes them fail with 68040 and 68060 cpus.
> this is needed for ? (I know this is beyond the scope of this list ;)    )

not really...

Ok. Some of your devices might contain registers that may only be accessed 
byte-wide, or word-wide.

68020/30 contained internal logic to break down bigger requests into
smaller chunks, if the device (or bus) requests this.

68040/60 dont do this anymore; this makes access to normal memory
faster, I guess, but you need an additional chip (68150, or integrate
it into your own logic) to interface them to smaller busses.

If you dont do this, code that use to work with 68020/30 will kill your device,
hang your machine, or at least not work.

Regards,
        -is