Re: ROMs replacement

From: Segher Boessenkool <>
Date: Tue, 18 Sep 2012 20:29:39 +0200
Message-Id: <>
> Problem is, you can't really tristate an input. No matter what, you  
> will always have the input stage visible as a load. Holds true with  
> TTL too.

You can cut it off, just like you can cut off an output.  On the NMOS
processes we're concerned with here (and probably most MOS processes)
this has _higher_ leakage than the inputs themselves though!

> But the real question is, what signals of the 6510 are controlled  
> by AEC? The 'A' stands for 'address', but does it also control  
> other signals including the data bus? From the 'scope readings I'd  
> say it also controls R/_W, but can't really say anything about the  
> data lines.

The 6510 datasheet claims AEC tristates R/#W, A, and D.


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Received on 2012-09-18 19:01:08

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