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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: Mike McCarty jmccarty at ssd.usa.alcatel.com
Date: Mon Jun 25 10:37:25 CDT 2001

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.

char *p="char *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
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