On 09/03/2012 12:37 AM, blstuart at
bellsouth.net wrote:
Does anyone know if Motorola ever made 6809s that
could function
either as 6809 or 6809E depending on some external signal, or perhaps
depending on how they were bonded out?
The reason I ask is that I've been playing with an SBC designed around
a 6809E. While working on writing the monitor on the first prototype,
it died with what looked like a bad CPU. So I ordered a replacement,
and while I was at it, ordered the parts to populate another board.
Both the board with the replacement CPU and the other freshly
populated board behaved the same way. After a little digging it
appeared that the E and Q clock signals that should be externally
driven for a 6809E were being driven by the CPU like for a 6809. I
took a chance and rewired it like a 6809 and sure enough it's working
now. But after numerous double checks, the chips definitely say
MC68B09E/00TA6/HEQB0014. Has anyone seen anything like this? Did I
end up getting a couple of chips that were mismarked? Is there a way
to make them behave as 6809Es?
Thanks in advance,
BLS
In a word, NO.
Most cases the solution is either the right part of supply the clock
externally
and create the E signal.
Allison