Re: ROMs replacement

From: Gerrit Heitsch <>
Date: Mon, 17 Sep 2012 18:44:16 +0200
Message-ID: <>
On 09/17/2012 12:01 PM, wrote:
> The NAND version looks like this:
> It has four pull-up resistors.

You can eliminate 2 of them since a truly unused input can just be tied 
to +5V directly. That means R304 and R301 can be replaced by a direct 
trace to +5V.

The other two you will need though since you have 2 inputs that need to 
be pulled to HIGH through a resistor in order you to be able to pull 
them to GND when needed without shorting the supply. I don't see how 
using a 148 would change that.


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Received on 2012-09-17 17:00:05

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