TTL and [Keyboard scanner]

[Harry Bissell]

TTL logic levels are les than .8 volts for low, and greater than 2.4 volts for
high. So if your design has diodes on the high side (4.3v) and resistors to
pull down all the way to "0" volts, it will work fine. 74HCT series c-mos has
TTL logic levels, also. Maybe you want to look into this family. Use a .1
decoupling cap on every device if you go with TTL, it is power hungry S at IT. 
:-)  Harry Bissell. Good luck.






BTW:: Check << www.netpower.no/~roarh/synth.htm >> if you care.
	Not much yet, but it'll all be there eventually.  :-)

-- 
.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.
 Hallgeir Helland       hhelland at usa.net      
    Evlogia           http://fly.to/evlogia   
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