drlegendre at gmail.com
Sat May 28 20:22:54 CDT 2016
Whoops, sent too soon..
Could someone also clarify what is meant by "gates" in this sense? Are we
talking about the gates (G) of a FET, as in Gate, Drain and Source - or are
we referring to the composite logic gates (NAND, etc.), built up of
multiple bipolar - or MOS - transistors?
On Sat, May 28, 2016 at 8:19 PM, drlegendre . <drlegendre at gmail.com> wrote:
> @Eric, All,
> Light a candle for those in the dark..
> If the min. clock speed is dictated by the ability of the gates to hold a
> charge, as the bits rot away as charge drains (someone said "minimize
> resistance to ground", but I believe they meant "maximize"?) , then what is
> limiting the max. clock speed?
> Is it just basic PCB stuff, like trace inductance, mutual / parasitic
> capacitance, etc? Or are there other, more critical factors? I can't
> imagine propagation delays could matter at these slow speeds.. requiring
> meandering of traces and so forth.
> On Sat, May 28, 2016 at 2:55 PM, Corey Cohen <applecorey at optonline.net>
>> > On May 28, 2016, at 1:31 PM, Eric Smith <spacewar at gmail.com> wrote:
>> >> On Sat, May 28, 2016 at 5:31 AM, Corey Cohen <applecorey at optonline.net>
>> >> I can't wait to buy one!!! I have a spare Replica-1 just waiting to
>> hook up to a Monster 6502.
>> > It doesn't run at full speed. It presently runs in the tens to low
>> > hundreds of kHz. If a Replica-1 can be run slower than normal, that
>> > might work. Other common 6502-based micros, such as the Apple II or
>> > Atari 400/800 will not work at low speed due to inherent timing
>> > requirements related to video generation and DRAM refresh.
>> >> Just need to wire up a single step switch and this thing will be
>> > If you wire single-stepping using the RDY line, that should work,
>> > though it will only single-step read cycles, not write cycles.
>> > You can't single-step the actual clock because it is dynamic logic.
>> The replica-1 uses a propellor chip for video and static ram so I don't
>> think it's that critical to timing.
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