CoCo 2 & 3 max speed

From: Roger Merchberger <>
Date: Wed Jan 28 20:15:44 1998

;-) Clearing the snow from my glasses, I saw John Higginbotham typed:

>Anyone know right off hand what the highest supported baud rate is for the
>RS-232 on a CoCo 2 or CoCo 3? Asking for a friend who thinks she can use a
>9600 baud external modem on it. (!)

Supported or possible??? There's a big difference, you know! ;-)

Supported IIRC is only 300 (maybe 600) bps for the CoCo2, and 1200 for the
CoCo3. I do remember many ads (adverts for our British friends, IIRC)
claiming flawless 1200 (coco1/2) and 2400 (coco3) bps speed for a CoCo.
Again, IIRC I heard rumors of someone actually getting 9600 bps thru the
bitbanger, but I'm sure that's will all interrupts fully disabled in RSDOS
with a memory-to-port (or vise-versa) transfer only -- no other functions
like video, disk or anything else so you were xferring totally blind.

This may also have been with a (Hitachi) 63C09* instead of a 6809, but I'm
not sure.

The place to ask would be the newsgroup news://bit.listserv.coco -- if you
don't have access to that group, just let me know. I'm subscribed to an
e-mail gateway to the list, so I can forward anything you need.


* Readers Digest version for those who don't know: Moto was looking for a
2nd source for their star 8-bit CPU at one point and hired Hitachi to build
them as well -- but Hitachi did too good of a job.

They doubled the accumulators, and like (A & B) = the D register, the other
two 8-bit regs could be used in tandem for a 16-bit... and all four could
be used in a limited fashion as a 32-bit register.

Also, even on straight Moto 6809 code, once the CPU is put in 6309 mode,
most people see a 15-20% overall increase in execution speed... there's
even a modified version of OS-9 just for the Hitachi -- called NitrOS-9.

Alas, I don't have anything like that, but from what I hear a NitrOS box is

All plug-for-plug compatible with our beloved Moto6809.
Roger Merchberger       | If at first you don't succeed,
Programmer, NorthernWay | nuclear warhead disarmament should *not*  | be your first career choice.
Received on Wed Jan 28 1998 - 20:15:44 GMT

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