Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!apple!agate!ucbvax!cue.bc.ca!mpratap
From: mpratap@cue.bc.ca (Matt Pratap)
Newsgroups: sci.electronics
Subject: help! 74ls48 display problem
Message-ID: <9102232331.AA12070@cue.bc.ca>
Date: 23 Feb 91 23:31:52 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 23


This may seem like a simple question, but I'm a simple guy :-)

I have made a 2 digit decimal counter and display using 2 74ls190's
(up/down decade counter) with 2 74ls48's (7 segment display driver).

I want the most significant digit (10's) to be blanked when it is
a '0'.  In theory, all I have to do is ground pin 5 (Blank '0' in)
of the 7448.  This doesn't seem to work.

Another method I tried was to invert the max/min line from the
74190 and tie it to pin 4 (blank out) of the 7448 (I think
this is permissible). This blanks the display on '0' and also
'9'.  A step closer, but not what I want, since I use '9'.

Is there any way to get this accomplished without any more
chips?

Thanks

-------------------------------------------------------------------------
Matt Pratap, Victoria B.C. -=- mpratap@cue.bc.ca  *  (Insert quote here!)
-------------------------------------------------------------------------


Brought to you by Super Global Mega Corp .com