[Coco] deluxe rs232 pak / MPI
aawolfe at gmail.com
Tue Nov 24 20:48:51 EST 2009
Thanks for all the hints, I just got it working in nitros-9! very cool
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:
>>>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
>> 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
>>>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
> 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:
>>>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.
>>>Coco mailing list
>>>Coco at maltedmedia.com
>> 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)
>> The NRA is offering FREE Associate memberships to anyone who wants them.
>> 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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