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 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
Keyboard Scanner sub-module
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widdly



Joined: Jun 25, 2007
Posts: 265
Location: singapore
G2 patch files: 2

PostPosted: Fri Jul 11, 2008 3:02 am    Post subject: Keyboard Scanner sub-module Reply with quote  Mark this post and the followings unread

I was looking at the schematic for this project and it's got me confused.

http://www.cgs.synth.net/modules/pic/schem_cgs25_keyscan_large.gif

Can the 74LS138 be run backwards? In Ken's diagram he has inputs connected to the chips outputs. Does that work? The data sheet for the 74LS138 has a gate diagram that suggests it wont. Anyone tried it this way?


EDIT

....Never mind...I see how it works now. It's outputting a voltage to the key, then the paralel port scans through all the keys and detects when the key that is on.

Last edited by widdly on Thu Aug 05, 2010 10:12 pm; edited 1 time in total
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otherunicorn



Joined: May 11, 2008
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PostPosted: Tue Jul 15, 2008 12:53 am    Post subject: Reply with quote  Mark this post and the followings unread

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