[Coco] What about the double speed upgrade?

[Joel Ewy]

It's been a while since I looked at Sockmaster's 4MHz upgrade, but IIRC,
it increases the clock speed for the CPU only.  E remains at 2MHz for
the rest of the system. 

However I also seem to remember that much of the speed increase would be
lost on the 6309.  I don't recall the exact details right now, but
essentially it had to do with the fact that the upgrade inserts extra
clock pulses during certain phases of the instruction cycle.  On the
6809 these would have the effect of speeding up some of the internal
processing that the CPU does between bus accesses.  But when the 6309 is
running in native mode, it already does some of this processing in fewer
clock cycles anyway, so you don't gain as much.  On the other hand, it
would give you some of the same benefits of running in native mode even
when you're running BASIC programs, etc.  And the 63C09 is rated for a
higher speed than the 68B09, so you wouldn't be overclocking it as
much.  I realize these details are incomplete.  Somebody help me out if
they are incorrect.

JCE


jdaggett at gate.net wrote:
> SPeed compatibility issues will exist with either processor when doing anything 
> outside the processor. All the existing peripheral devices would have to be of 
> equal speed grade with the E clock. 
>
> On instructions that are internal to the processor there is no real major issues 
> except in software timing loops. 
>
> james
>
> On 4 Jan 2007 at 19:16, Leon Howell wrote:
>
>   
>>> The HD6309E is 100% compatible software with the MC6809E. The revesrse is 
>>> not true due to the extra registers and increased instruction set contianed 
>>>       
>> inthe 
>>     
>>> HD6309E.
>>>
>>> james
>>>
>>>       
>> I meant compatability problems caused by the speed.
>>
>>
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