[Coco] deluxe rs232 pak / MPI

Tue Nov 24 20:48:51 EST 2009

Thanks for all the hints, I just got it working in nitros-9!  very cool
-Aaron


On Tue, Nov 24, 2009 at 8:20 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:
> On Tue, Nov 24, 2009 at 7:30 PM, Gene Heskett <gene.heskett at verizon.net> wrote:
>> On Tuesday 24 November 2009, Aaron Wolfe 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.
>>>
>> The slot switch must be to the slot the pack is in at powerup unless the MPI
>> has been jumpered.  If it has been jumpered, then the packs eprom should be
>> pulled as there are other packs you may have plugged in that will also have
>> that as an exec address.
>>
>
> hmm.  I can't get the EXEC to work even when the rs232 pak is directly
> connected to the CoCo, no MPI.  Could this mean a bad rs232 pak?
>
> I think I have to have the MPI's switch set to the slot my drivewire
> rompak is in so that the HDB DOS rom loads.
> Does this mean I cannot use the rs232 pak as the same time, or maybe
> this just means I must wire the IRQ lines together?
>
>>>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?
>>
>> I believe that most folks put it in the front slot, aka slot 1, byte
>> $FF7F=00.
>>
>
> is there a setting in NitrOS-9 to tell it to set FF7F to 00?  Would
> this break the drivewire rompak in another slot?  (this rom is how I
> am booting nitros9)
>
>>>do i need to wire all of the interrupt lines in the MPI together to
>>>make this work?
>>
>> Mine has been so wired for about 22 years, excellent idea if for no other
>> reason than all IRQ's _do_ get through to the cpu.  In your case, it sounds
>> like the IRQ from data rx'd may have gotten through, but the slot switch, or
>> the logic at $FF7F, is preventing the IRQ service routine from accessing the
>> pack, which in turn clears the IRQ, so you effectively have an IRQ stuck on.
>>
>>>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.
>>
>> There is a possibility that the Aztec inverter supply in the pack has gone to
>> that great retirement pasture.  Since you have the MPI, you have the plus and
>> minus 12 volt supplies the chips need available in the mpi.  You have to
>> remove the Aztec assembly, and wire the cards edge connector to feed those
>> voltages in where the Aztec was feeding them.  ISTR I had to superglue a
>> couple of strips of thin copper plate into the blank spaces to do that.
>> PITA, but it works for me, and has been for at least a decade.
>>
>> That rewired pack will NOT work in a coco3, as the coco3 has no -12 volt line
>> at all, and the load on the +12 line may be the straw that writes fini to the
>> coco3's power transformer if its not actively cooled.
>>
>
> I guess that option is out, I am using a coco3.   But does that mean I
> could never use the rs232 pak on a coco3, since the coco3 have no -12v
> line?  sorry if I'm being dense.
>
>>>-Aaron
>>>
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>>>
>>
>>
>> --
>> Cheers, Gene
>> "There are four boxes to be used in defense of liberty:
>>  soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
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>>
>> Oh don't the days seem lank and long
>>        When all goes right and none goes wrong,
>> And isn't your life extremely flat
>>        With nothing whatever to grumble at!
>>
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>