[Trac #1297] Pressing two adjacent keys at the same time fails

Zarro Boogs per Child bugtracker at laptop.org
Wed Apr 11 23:45:15 EDT 2007


#1297: Pressing two adjacent keys at the same time fails
-----------------------+----------------------------------------------------
 Reporter:  cjb        |        Owner:  mlj      
     Type:  defect     |       Status:  closed   
 Priority:  normal     |    Milestone:  Untriaged
Component:  keyboards  |   Resolution:  invalid  
 Keywords:             |  
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Comment (by AlbertCahalan):

 Replying to [comment:3 cjb]:
 > I'll show this to someone at 1cc, because I don't think the explanation
 above quite covers it -- if a zone can only provide one signal at a time,
 why can I get "a" and "s" (or indeed any combination other than "rt" or
 "yu") at the same time?

 The first explanation (zones) makes sense. The second explanation
 (sealing) does not make sense.

 It's a matter of cost. One can argue about this being a good or bad place
 to cut corners. Supporting arbitrary key combinations requires a
 controller chip with N wires for N keys. (plus misc. non-key wires) A more
 limited solution requires a controller chip with 2*sqrt(N) wires for N
 keys, assuming N is a perfect square. With about 80 keys, that's 80 vs.
 18.

-- 
Ticket URL: <http://dev.laptop.org/ticket/1297#comment:4>
One Laptop Per Child <http://laptop.org/>



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