[Coco] Is the 6309 worth it?

[Roger Merchberger]

Rumor has it that Leon Howell may have mentioned these words:
>I've heard the 6309 only makes the CoCo 15% faster. I've heard it makes some
>things up to 10 times as fast. What does it make 10 times as fast, and 
>would I
>really notice the improvement? I've heard NitrOS-9/6309 is about twice as
>fast, but I have NitrOS-9/6809, and it seems at least twice as fast as OS-9.

There's 3 "modes" to the 6309 - 1) pure compatibility mode - to the 
software, it's a 6809. 2) "Enhanced 6809" mode: no new instructions, but 
some instructions take fewer cycles to complete - that's the 15% number 
you've heard. That can goof up some timing loops in games & whatnot. 3) 
full 6309 Mode: There are extra registers, extra instructions, extra, 
extra, extra and some instructions execute even quicker, IIRC.[1]

You get 2 extra 8-bit accumulators, which can also be utilized as a 16-bit 
accumulator, and *also* with the existing 16-bit accumulator (D) to make a 
32-bit accumulator{!} amongst other things.

I dunno about the "10x faster" bit, but software written to take advantage 
of the 6309 can be quite snappy, comparatively (yet vaguely ;-) speaking.

>I've also heard the 6309 is very rare and very sensitive to static, etc.,

It's CMOS -- everything CMOS is static-sensitive.

>  and
>of course I would have to cut out my 6809 to avoid destroying my motherboard

Or pay someone who has the tools that can preserve both the motherboard & 
CPU. I have a very good vacuum-pump desoldering gun, and have removed 
several 40-pin chips without harm, but my spare time quotient is so far in 
the negative that it'll take me to next month to catch up to last week.

>(my soldering skills stink) but I was thinking of installing a double speed
>upgrade, so I'll have to do that anyway. I just don't want to spent all that
>time and money installing a new os and a chip that will go up in smoke the
>first time the cat walks by.

If the computer you're doing your email on right now won't "gesplode" due 
to your cat, your CoCo certainly won't either... 99.99999% of processors 
made in the last 15 years are CMOS. OK, maybe not "quite" but durned near 
all of 'em for consumer use are, and if your hub, switch, router, alarm 
clock, Athlon and Pentium are safe from your cat now, no need to worry. ;-)

>  It seems like a 32 mhz clock crystal (2.0/4.0
>mhz) would do the same thing, and be less sensitive, but what about
>compatibility?

It wouldn't do "the same thing." The 6309 gains speed due to efficiency, a 
crystal swap gains speed via overclocking, and remember: you're 
overclocking the system buss. So, not only will your CPU overheat (because 
dollars-to-donuts it can't dissipate that much heat with convective 
cooling) you're also overclocking the memory (which won't be none-too-happy 
about that!) and the GIME (which quite likely will gesplode) and of course, 
the video circuitry, which means you won't be able to see how fast your 
computer's running before it fries.
:-O

If I had time to tinker right now, the 6309 is definitely worth it.
;-)

Laterz,
Roger "Merch" Merchberger

[1] I've never had a 6309, so I'm quoting from my admittedly poor memory. ;-)

--
Roger "Merch" Merchberger   | Anarchy doesn't scale well. -- Me
zmerch at 30below.com.         |
SysAdmin, Iceberg Computers