AVR-Chat

Data sheet definitions are sometimes wrong as are manuals. I found that out 
the hard way with the mega168. However, a logic 1 is presumed to be the 
"high" logic 1 and a logic 0 the "low". Remember ECL. Bassackwards.
I'm working on a system where the ground is -5v dc generated by a hybrid PS 
and the positive supply is AC neutral.
D

----- Original Message ----- 
From: "John Samperi" <samperi@ampertronics.com.au>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, August 31, 2005 4:45 PM
Subject: Re: [AVR-Chat] Pull down resistors??


> At 04:15 AM 1/09/2005, you wrote:
>> > Ummm - a low voltage (0v) is a logic zero. A high voltage (5v) is a
>> > logic one.
>>
>>    Not according to AVR data sheets, it's not.
>
> The convention of using logic 0 for 0 volts
> and logic 1 for a high (be it 5, 1, 3 12 or 100V)
> was established before micro controller were thought
> of and therefore it has nothing to do with Atmel.
>
> Regards
>
> John Samperi
>
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