[Coco] Disto SC (NOT) needed

[Joel Ewy]

Darren A wrote:
> On 11/15/08, Roger Taylor <operator at coco3.com> wrote:
>   
>> ...
>>
>> I typed those POKEs and the problem was reproduced.  I tried another
>> 64k ECB CoCo 2 and now my "controller" works.  So, I suppose both of
>> my CoCo 1's have the NMI line screwed up.  Is there a fix for THAT ?  :)
>>
>>     
>
> Roger. The problem is almost certainly a blown HALT line inside the
> CPU. I've had two such processors which behaved normally except when
> disk I/O was performed. In both cases, tests revealed a blown HALT
> line. The 6809 seems to be plagued by this problem. Replacing the CPU
> will most likely fix the CoCos so they can once again use disks.
>
> Darren
>
>   
Hmm.  Could you use a Super Controller II with a CPU that has no HALT
line?  :)  (Probably not easily in practice, since the SCII runs in halt
mode until the OS-9-only no-halt driver is loaded, and how will you boot
OS-9?  Can you boot OS-9 over Drivewire?  Or you could burn OS-9 into
EPROM.  I guess you could also use it in a cassette only system...)

JCE
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