AVR-Chat

John -
To go one step further OT, I like your word use "ASS U ME" ,
and would like to contribute " EM BARE ASS".  ( "em" meaning "to cause")
Ken



John Samperi wrote:

>At 12:59 PM 2/09/2005, you wrote:
>  
>
>>>>Witness RS-232-C and IBM,for example.
>>>>        
>>>>
>.......................
>  
>
>>   Why would I have had an RS-232 intercae connected?  I was reading a
>>bank of pushbutton switches.
>>    
>>
>
>Thousand apologies :-[
>
>You did mention RS232 and having to reverse the logic...
>so I ASS U MEd (mainly me in this case :-) )....but you will
>be surprised how many people connect RS232 DIRECTLY to the
>UART and wonder why is doesn't work. This comes in a way
>from some micro controllers that allows you to reverse
>the polarity of the signal from the UART giving you in
>effect a 5V RS232 port which does work in many modern
>PCs but would create smoke in an older RS232 link
>which IIRC may go as far as +-25V.
>
>As far as polarity convention I always ASS U ME (that
>word again) that we talk about positive logic UNLESS
>the manual refers to negative logic. i.e. in/out of
>the UART is positive logic whilst the physical RS232
>link is in fact negative logic where a positive logic
>signal represents a 0.
>
>Have we strayed enough away from the original topic
>yet or shall we do a bit more? :-)
>
>
>Regards
>
>John Samperi
>
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