Re: Commodore joystick ports

From: Daniel O'Shea (dan_at_ozramp.net.au)
Date: 2007-04-08 00:52:14

Jim Brain wrote:
> I'm not sure I can shed light on whether the ideas presented work, but I 
> know I tried the transistor idea and some others when I was trying to 
> emulate the paddle and had no luck.

Jim, are you certain about the transistor idea not working though? in 
the old thread:

http://www.softwolves.pp.se/misc/arkiv/cbm-hackers/9/index.html#9813

...you say, "I did not try a current approach (Analog is my weak 
subject), but wouldn't I need some sort of analog input to the 
transistor in order to bias it to a certain level?" and then later: "I'd 
travel down the path, but as of last night, the idea used by the
1351 designers and Hársfalvi noted in his project is working pretty
well"?

Pasi Ojala wrote:
 > I am also no analog expert by any means, but it still seems
 > to me that it would be possible to simply use a series resistor
 > to convert the external voltage level into a current.
 >
 > When used "normally", the voltage is constant and the resistance
 > changes, changing the current that charges the capacitor.
 > If the voltage changes, but the resistance remains the same,
 > the current that charges the capacitor changes. Both cases
 > should seem about the same to the capacitor..

...so which is it to be then? a transistor, or a resistor? (isn't a 
transistor a type of resistor anyway?)

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