1 Jul
2014
1 Jul
'14
8:04 p.m.
A question for someone with specialist knowledge in
6809s....
Re 6809Es
... It seems that most
of them on eBay are counterfeits; the last lot I bought were all
fake, marked Japan on the front, but China on the back. They
looked very convincing, with the markings etched very nicely,
rather than printed. Unfortunately, they didn't work.
As it turns out, I have had some success getting 6809s on eBay,
but mostly the straight ones, not the Es. In fact, I ordered some
Es a few years ago from a hobbiest distributor, and even though
they were marked E, they were really straight 6809s. Nothing
else looked amiss, so I figure they were mismarked.
So - can anyone explain the difference, in terms that
aren't
too hard to understand?
The primary difference is whether there's an on-chip clock
generator. For the E, you have to generate the two-phase
clock externally. For the non-E part, you can connect a crystal
or directly feed a single 4x clock.
And - is there any hope of modifying
a machine that would normally require a 68B09E to be able to
use a 68B09?
Without seeing the full design, I can't really say. However, I
encountered the whole issue when doing a 6809 SBC and did
end up converting what I had originally designed for 6809Es to
6809. I did the second rev of the board with jumpers so you could
use either one. If none of the rest of the machine uses any of
the processor signals that are unique to the E part, then making
the changes to use a 6809 aren't too major. How feasable it is
in practice really depends on the rest of the design.
BLS