[Coco] ceramics ...

[mmarlett at isd.net]

james,

Common knowledge for most. Kind of like telling my Son that just because
the RPM gauge runs in the RED doesn't mean the engine will run forever
there.

The GIME, TCC1014A....Same thing here, sure you can run it faster. I have
modified the XTAL to 32MHZ for a true 2MHZ and adjusted the internals of my
monitor to compensate. My experience has been that the GIME/motherboard or
whatever becomes unstable. This is my personal experience. Roll them back
and they work just fine. All my mod'd machines have all been returned to
stock speeds due to reliability reasons.

What overclocking have you done to the GIME and what were your results?
Please provide revision information, if relevant to your test cases.

Mark


>Kevin/Mark
>
>Digital IC's speed specification is the maximum speed for a device such as
there 
>will guarenteed 100% compliance to the spefications of the IC. This is by
far not 
>the fastest the IC can run. Speed is often determined at die probe and by
which 
>package the die is placed in. Several parameters have to be taken in. Of
one of 
>the primary parameters of concern is heat. While the package temperature 
>maybe warm, but the actual die temperature can be as much a twice the
outside 
>package temperature. The main goal is to keep the die temperature below
150 
>degrees C. Heat is the ultimate killer of semiconductors. Above 150 C the 
>physics of the semiconductor breaks down and all kinds of nasty things
happen. 
>Eventually, in MOS devices, the channels that allow electron mobility
fail. Now 
>you have a piece of silican  that is no longer functioning. 
>
>Kevin you are right in one aspect, the ceramic parts can operate at higher
clock 
>speeds than say the common injection molded palstic parts. Ceramic
conducts 
>heat better the plastic. 
>
>The second parameter that affects digital IC speed is the basic geometry
of the 
>transistors used to make the gates and the fabrication process, NMOS,
HMOS,  
>CMOS bi-CMOS and so forth. Smaller geometry transistors  have higher gain 
>bandwidth product and thus smaller propogation delays between the gate and

>drain. 
>
>If you can heat sink the pakage sufficiently a digital IC can be clocked
as fast as 
>it can accept it. That  generally is when the pin to pin propogation delay
is slower 
>than the clocked data. Generally speeking,  the propogation delay through
the IC 
>should not be more than 25 to 50% of the clock cycle. 
>
>
>The GIME chip will handle higher clock speeds. T he problem is that to get

>proper HSYNC and VSYNC and color info correct it must be clocked at the 
>perscribed frequency of 28.6363 MHz. Faster or slower will change internal

>timings that allow for proper NTSC and CG A video modes.
>
>james
>On 3 Sep 2004 at 4:15, Mark Marlette wrote:
>
>Date sent:      	Fri, 03 Sep 2004 04:15:12 -0500
>To:             	CoCoList for Color Computer Enthusiasts 
><coco at maltedmedia.com>
>From:           	Mark Marlette <mmarlett at isd.net>
>Subject:        	Re: [Coco] ceramics ...
>Send reply to:  	CoCoList for Color Computer Enthusiasts 
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>> At 9/2/2004 09:04 PM -0700, you wrote:
>> 
>> Kevin,
>> 
>> Most parts have a designed clock that they were certified at and
>> assigned when they were tested at their manufactured date. What are
>> those clock speeds of the said chips? Seems to me to be a data book
>> look up process. If theory doesn't work for you then just hook them up
>> and try them out at the speed you want them to run. A bit of work
>> since they are just chips and require a bit of work to connect up and
>> test. Let us know what you find out though. Have some plan(s) for a
>> new CoCo project here?
>> 
>> Mark
>> Cloud-9
>> 
>> 
>> >Hi,
>> >
>> >         No hardware. Just a pair of chips. So the question refers to
>> >         
>> > them. Think they would run at 14.3181818?
>> >
>> >                                   kevin
>> >
>> >Mark Marlette wrote:
>> >>At 9/2/2004 11:57 AM -0700, you wrote:
>> >>Kevin,
>> >>Overclocking is generally not a good thing to do but it depends what
>> >>you are trying to do. For instance, overclocking the CoCo3 is not a
>> >>good thing due to the GIME. Can you tell us a bit more about the
>> >>hardware that these CPUs are connected to? Regards, Mark Cloud-9
>> >>
>> >>>Hi,
>> >>>
>> >>>         I have a 68010 and a 68008. They are both 8s. Any
>> >>>thoughts as to how high they could be SAFELY overclocked?
>> >>>The plain 6809e in my deuce seems to run fine at 1.7 for
>> >>>extended periods. But it does have a heat sink.
>> >>>
>> >>>                                   kevin
>> >>>
>> >>>Stephen H. Fischer wrote:
>> >>>
>> >>>>Hi,
>> >>>>I thought I had one, but it is a 6800. I found a 6820 and a 8008.
>> >>>
>> >>>
>> >>>
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