[Coco] 6809 computer boards (was French Translation Compensation)
jcewy at swbell.net
Wed Nov 21 00:59:21 EST 2007
jdaggett at gate.net wrote:
> On 20 Nov 2007 at 17:08, Joel Ewy wrote:
>> Frank Swygert wrote:
>>> There are plans for a 6809/6845 based computer here:
>>> http://www.dunfield.com/products/projects.htm. I read about it --
>>> uses a 14.xx Mhz crystal for everything and runs around 7 Mhz (uses
>>> overclocked 68B09E). Not sure if the floppy controller chip used is
>>> available any more though.
>>> There don't seem to be any US manufacturers using a 6809 for
>>> anything now. The 68HCxx controllers pretty much took over whatever
>>> market there was for the 6809. Maybe NitrOS-9 should be ported to
>>> something like a 68HC11, which might be usable in a CoCo3 like
>> Of course, now we can do 6x09 in FPGA... Who needs dedicated silicon?
> Right now NOS of dedicated silicon is still slightly cheaper than FPGA. John Kent's CPU09
> core does fit into a XC2S200 chip with about 65% of the device utilized. This is optimized
> for speed. One could the sacrifice some speed for a smaller area. Also going above about
> 300K gate equivalent devices are all in BGA packages. That is without a doubt not
> solderable for most hobbyists. Cost is about $35 for 208 pin QFP in single unit with
> configuration prom.
> The Spartan 2 line of Xilinx chips are the only one that will tolerate interfacing with 5 volt
> logic. The Spartan 2e and Spartan3 series will not tolerate 5 volt logic levels. Not certain
> about Altera, Lattice or Actel.
True enough. At this point, you can get a CoCo 3 from Cloud 9 for $35?
$40? This is a great deal. You can also get a Dragon from California
Digital for about the same price. But for about three times the price
you can get an FPGA development kit, download Gary Becker's code, and
have a CoCo 3 SOC which runs at about 10x the speed of the CoCo 3, it
will work with a VGA monitor, and you don't even need to get a disk
controller for it.
When I said "Who needs dedicated silicon?" I certainly wasn't suggesting
anybody ditch anything packaged in ceramic or plastic with batwings on
it. If my son doesn't take an interest in the CoCo I'm probably going
to take mine to the grave. But I don't think we need to be too
concerned that the only "real" 6809 boards being produced are
So about the logic levels: aren't there chips out there that can bridge
between 2 / 3 and 5 volt logic levels? Is that really a deal-breaker,
or just an unfortunate complication?
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