Date   : Mon, 03 Mar 2008 18:14:27 +0100 (GMT)
From   : johan@... (Johan Heuseveldt)
Subject: TUBE chip, accessing 'Parasite' side

Hi all,

I'm sort of 'designing' a CoProcessor with a 6809 - 2 MHz version (68B09).

I refound the schematics for the internal CoPro 80186, but couldn't find
anything else. With my own 6502 external 2ndProcessor, I've investigated a
few things. It appears that the power connections to the TUBE chip are more
advanced than I first assumed, which makes sense as this chip - besides the
logical model for the TUBE software protocols - must also handle two
independant power connections, and some safety precautions are apperently
necessary!

Further, I was looking at the access of the 3 MHz 6502 to the TUBE chip,
and found it was different than expected. Investigating this board any
further will be a project of its own, I suppose, so I tried to look for it
elsewhere. No luck though.
The 80186 schematics are also vague (to me) in this respect.

The '004' document for the TUBE doesn't say anything how fast the parasite
side can/may be accessed. Even an pin description is without pin numbers.

So, does anybody know how fast the parasite side can be accessed by the
processor?
I assume that at least for a 2 MHz processor, no slow-down is needed?

TIA


greetings,
Johan

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

  The best place is a Riscy place
 
He who hesitates is constipated.