Running with a real 6809E

[tcdev]

Tonight we got Tutankham running with a 6809E plugged-in to Chris's 6809/68K expansion board he designed for his DE2. The 6809 is running at 1.5MHz.

The real reason he designed it was two-fold:
(1) allow side-by-side development of a 6809 core (don't hold your breath)
(2) allow side-by-side development of a 68K core (and I don't see anyone cross-breeding pigs and albatrosses anytime soon, do you?)

Of course it has the added benefit of allowing us to build 6809/68K designs without having to (initially) include a CPU soft core - the end result being greatly reduced build times!

Now all I need to do is tie him to his DE2 and whip him until he gets the 68K working - for *all* definitions of "working".

[MiniMorph]

You can get both 6809 and 68000 cores from opencores so why would you want to wire a real one ???

I am puzzled !!!

[tcdev]

The original ultimate plan was to develop a 68K core - before the 68K core was released on opencores.

So my colleague developed a DE2 add-on board that would accept both a 6809 and 68K processor. The idea was to use this board to develop a 6809 as a stepping-stone to development of a 68K core.

FYI the 68K core released on opencores is not complete. For instance, it does not implement the external FC codes for interrupt acknowledgement cycles. There are other features missing as well.

In the interim, we want to hook a 68K CPU up to the DE2 so we can start with development of a few 68K-based designs, whilst we wait for the 68K cores to mature. Also, both the 6809 and 68K cores take a significant time to synthesize, so without having to worry about incremental compilation and/or region locking, we can simply use external CPUs to speed up our development cycle. We also don't have to worry about core bugs slowing us down.

The 1st step to getting a 68K CPU running was to wire up the simpler 6809 core, to prove the design of the board and the CPLD on the board. That's where we're at right now.

The next step is to get the external 68K running.

[MiniMorph]

MikeJ of FPGA Arcade has his own 68000 coming too I think. He is working on an Atari ST core.

I am somewhat stalled on my boot loader project as I really need some Terasic / Altera DE1 cores to load and offer services with my boot loader.

I think 2008 will be a great year for the Retro FPGA world !

All the best.