[Coco] deluxe rs232 pak / MPI

[Arthur Flexser]

The CoCo 3 must be put into the ROM mode before the pack's firmware can be
accessed.  Using EXEC &HE010 instead of EXEC &HC000 accomplishes this.
Though the firmware in the RS232 Pak is so poor it is hardly worth
accessing.  The change from C000 to E010 for Rompaks was noted in a little
slip of paper that RS put in the CoCo 3 carton.

Art
On Tue, Nov 24, 2009 at 7:05 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:

> Hi,
>
> I just acquired an rs232 pak and MPI.  The MPI seems to work fine with
> my coco 3, at least my drivewire rom pak works fine through it.
> I haven't been able to get the rs232 pak to work in basic or nitros9,
> with or without the MPI.  I have the original documentation from
> tandy, was wondering if things have changed for use in the coco 3.
> Also I have the 6309 instead of 6809, maybe this has some effect.  The
> MPI is 26-3024 "updated for use with the coco3".
>
> the docs say to do "EXEC &HC000" or "EXEC 49152" to access the setup
> routine in the pak's rom.  This results in various lockups on my coco
> 3.
>
> looking through the nitros9 source I see that FF68 is base address for
> T2, and FF6C for T3.  Tried both with basically the same results.  I
> see there is a compiler flag for MPI usage, it is set.  I am not able
> to try nitros9 without the MPI because currently I must boot from
> drivewire  (really looking forward to that SD card pak, if you're
> listening Roger :).  the rs232 pak does not appear to have been opened
> for any modifications, label covering the screw was intact until I
> opened it just now to look for obvious bad components.
>
> when I "iniz /t2" or /t3, sometimes I get error 246, sometimes it
> works.  when it works, an irq routine shows up in the "irqs" command
> and the device is listed in "devs".  however, all attempts to pass
> data do not seem to work.  sometimes the coco locks up about the same
> time data is sent into the port, so I assume this means something
> somewhere is working, sort of?  might just be coincidence to be
> honest.
>
> should I put the rs232 pak in a specific slot of the MPI?
> do i need to wire all of the interrupt lines in the MPI together to
> make this work?  saw some posts about that.
> any tests I can do in basic, with the rs232 pak directly connected?  I
> saw a post about peeking values, they said:
>
> > ?PEEK(65384) usually reports 0 initially
> > ?PEEK(65385) usually reports 16 initially
> > ?PEEK(65386) and ?PEEK(65387) should report 0 initially
>
> the answer in the thread was that the user doing the troubleshooting got:
>
>
> ?PEEK(65384) 0
> ?PEEK(65385) 112
> ?PEEK(65386) 0
> ?PEEK(65387) 0
>
> I also get exactly these results, if that means anything.
>
> Basically I am not sure if the rs232 pak works, it was in storage for
> many years.  I am completely new to using an rs232 pak or an MPI, and
> actually new to OS-9 as well, so there are a huge number of unknowns
> here.  any hints or recommended practices are much appreciated. I'm
> not sure what tests to do to start eliminating possibilities.
>
> -Aaron
>
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