Re: What is the quintessential Apple II?

[Roger Johnstone <roger@roger.geek.nz.removethisbit>]

In <z8ydneDy1tEgSjbYnZ2dnUVZ_oninZ2d@comcast.com> Michael J. Mahon wrote:
> Dave Althoff, Jr. wrote:
>> Michael J. Mahon <mjmahon@aol.com> wrote:
>> : Roger Johnstone wrote:
>> : > 
>> : > We made a new board with a single 8-pin micro on it which 
>> : > performed both  functions. The resistor for the variable time is 
>> : > read by the micro  charging up a capacitor, then timing how long 
>> : > it takes to discharge it  through the resistor. I'm surprised no-
>> : > one thought of doing that before ; o)
>> : 
>> : Yes, that's a favorite trick for cheap analog input.
>> 
>> I hope you understand the significance of...I guess it was Roger's 
>> comment, including the "I'm surprised no-one thought of doing that 
>> before  ;o)", and *exactly* why he said it...  I've been away from 
>> here for a while, so I don't know what the 'apple ][  geek quotient' 
>> of the current population is.  But that is exactly how the  Apple ][ 
>> paddle inputs work, discharging an onboard cap through a 150-ohm  pot 
>> in the paddle...
> 
> It's 150k ohms, but I thought his "no-one thought of doing that 
> before" applied to the particular microcontroller application he was 
> discussing.
>
> It's an old trick, and I'm sure the Apple II wasn't the first to use 
> it.

I was well aware it was an old trick and was just trying to get the 
thread back on topic, as most people in this group will have seen it 
used, or at least heard about it, with reference to the Apple II paddle 
inputs.

-- 
* Roger Johnstone, Invercargill, New Zealand -> http://roger.geek.nz
* PS/2 Mouse Adapter for vintage Apple II or Mac
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