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[DPRG] reading a Cds via Port E on a HC11

Subject: [DPRG] reading a Cds via Port E on a HC11
From: Ralph Tenny rten at metronet.com
Date: Mon Jun 25 10:50:28 CDT 2001

If the processor's input protection can be verified, external limiters 
wouldn't be needed. If there is a chance you might use another processor, 
use the limiter anyway. Like chicken soup -- couldn't hurt!
Ralph

On Mon, 25 Jun 2001, Mike McCarty wrote:

> On Sat, 23 Jun 2001, Ralph Tenny wrote:
> 
> > What is the voltage swing [from light on Cds (low voltage) to no light on
> > Cds (high voltage)} output from the Cds? If the high voltage exceeds 5
> > volts, not only must you use a resistor, the pin on Port E must have a
> > diode clamp to +5v to limit tthe voltage applied to port E:
> > 			+5v
> > 	                   |
> > 			   -
> > 			   ^
> > 			   |
> > 			   |			
> > 	Cds-------\/\/\/\-------PortE
> > Ralph
> > 
> > On Sat, 23 Jun 2001, montgomery f.
> > tidwell wrote:
> 
> I thought the A/D inputs had internal clamp diodes. In fact, the
> Motorola documentation implies that *all* inputs are diode protected.
> 
> Mike
> -- 
> char *p="char *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
> This message made from 100% recycled bits.
> I can explain it for you, but I can't understand it for you.
> I don't speak for Alcatel      <- They make me say that.
> 


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