On Mon, 15 Oct 2001, Jean-Francois Lord wrote:
> Hi,
>
> 5.48
>
> I've been staring at this truth table for two hours now and everything I
> try is nowhere near what I need. I don't understand how I can get active
> high combinations to represent the number of an active low input. A hint
> about what kind of trickery I need to use would really make my day.
Maybe all you need to do is to stop staring at the existing table,
and to draw the table for the circuit that you want from scratch
(pretend that you are designing the circuit that the problem specifies
without using any MSI component, but only draw the truth table).
Then you should compare the table that you got with the table
8-23 and see how you should connect your I0_L to I7_L inputs
and you A0_H to A2_H outputs in an existing 74x148. Make sure
that you make the active high/active low labeling clear.
Cheers,
Nelson
/
\ / / Jose Nelson Amaral - amaral@cs.ualberta.ca
) / ( Associate Professor
/ / \ Dept. of Computing Science - University of Alberta
( / ) Edmonton, Alberta, Canada, T6G 2E8
\ O / Phone: (780)492-5411 Fax: (780)492-1071
\ / http://www.cs.ualberta.ca/~amaral
`----'
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