>I managed to get a VIDC20 data sheet from Acorn's web site before it 
>disappeared. It is an ARM data sheet so in theory you should be able to get 
>one from ARM. I wish now that I had kept the PostScript file.
>You should also be able to get ARM6 and ARM7 data sheets from 
>ARM. For the SA110 and derivatives the data sheets are available at
>http://developer.intel.com/  At least they were when I looked about 6 months 
>ago. I can't help with IOMD.

The ARM7500 has a lot in common with the RiscPC chips; it includes both VIDC 
and IOMD functionality.  I think you can download a datasheet from the ARM web 
site.

p.