[Coco] Dynamic RAM Q

Phill Harvey-Smith afra at aurigae.demon.co.uk
Fri Oct 6 21:03:48 EDT 2006

Robert Gault wrote:
> Phill Harvey-Smith wrote:
>> <snip>
>> One final curious thing about this setup is this, if I turn the 
>> machine on, type a 2 line 10 Print "Phill was here "; 20 Goto 10 type 
>> program, and run it, it runs. If I then turn the machine OFF for 5 
>> seconds and then back on again, and type RUN it's still there !!!! I 
>> have also noticed this on some CoCo 1/2 models too, so much for 
>> Dynamic ram needing to be refreshed :) :) :)
> Try that with a voltmeter on the +5v line. It would be interesting to 
> know whether the power supply caps store enough energy to keep the RAM 
> alive for several seconds.

Tried it, the voltage fell away to about half a volt in about a second, 
so I don't think it's that. The odd thing is it doesn't do this with the 
normal 4164 / 4116 chips in it, it's really odd, I'd be less surprised 
if this where static RAM but it's defiantly dynamic, so should decay if 
not being refreshed, even if the power is still on.



Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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