Martin McCormick wrote:

>       Thank you.  If it just does or and nor, it may not be
>practical for what I need which is to look at several outputs of
>a counter and provide a reset when a hard-wired constant is
>reached.  For that, one needs to know when the counter's inputs
>in question are all high.  I'd have to invert every single input
>to get an and gate.
>
>Declan Moriarty writes:
>  
>
>>It's an 'or' or a 'nor' gate. 
>>
>>Use OR & invert your main output. Connect 8-16 into any input for a 15 input 
>>gate. To make 16, you'd need an extra 'or' gate. That's how it seems to me.
>>
For a complete datasheet:

>>    
>>
> http://www-s.ti.com/sc/psheets/schs045a/schs045a.pdf

On page 3-139 (bottom of the page) you can find the possible output 
boolean expressions, on page 3-140 the function truth table.
You  need 2 IC's, both programmed as NAND gates.

The first 8 bits are connected to the first CD4048B. The EXP input of 
the first CD4048B must be low.

The other 8 bits are connected to the second CD4048B.
When you connect the output of the first CD4048B to the EXP input of the 
second CD4048B you will get a 16 input NAND.

Regards, Tinco Brouwer.

-- 
Author: Tinco Brouwer
  INET: [EMAIL PROTECTED]

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