[Coco] Update: os9gen on 128k coco3, rs323 pack

[Michael Furman]

On Feb 15, 2009, at 11:42 AM, Steven Hirsch wrote:

> On Sun, 15 Feb 2009, Gene Heskett wrote:
>
>> On Sunday 15 February 2009, Steven Hirsch wrote:
>>> On Sun, 15 Feb 2009, Michael Furman wrote:
>>>> I tried using the rs232 pak ROM and it seems to hang occasionally.
>>>
>>> There's an obscure problem with interrupt handling that might be  
>>> behind
>>> the hangs.  I have no personal experience with it, but it's  
>>> written up in
>>> "Tandy's Little Wonder" (Farna Systems?).  IIRC, interrupts are not
>>> properly shared between the cartridge slot and the GIME with the end
>>> result being that SIO interrupts can be lost.  Again, just  
>>> speculation
>>> that this is the issue!
>>>
>> There is about a 100/1 chance that is correct.  The fix is to  
>> remove three of
>> the 4 pullup r's tied to each card socket pin 8, and then jumper  
>> all sockets
>> pin 8's together.  This allows the IRQ to get through to the coco  
>> and be
>> serviced regardless of where the slot switch is, or what slot was  
>> last
>> selected by the software.
>
> Gene,
>
> I don't think he's using an MPI.  The problem I'm referring to is  
> internal to the computer and has to do with how the cart interrupt  
> is routed to the CPU.

Gene and Steven -

Can you cite some more exact references to articles on these mods,  
like to files on maltedmedia or rainbow issues etc.?  I am using a MPI  
btw... Otherwise I couldn't have the  FDD and serial ports connected  
at the same time.  I'll also do some searching in GMANE to see if this  
has been discussed before (I'm certain it has been, both topics seem  
familiar)

Thanks,
--Mikey