Re: VIC-20 Paddle Notes

From: Jim Brain <>
Date: Mon, 23 Nov 2009 01:46:48 -0600
Message-ID: <>
Daniel Kahlin wrote:
> On Sun, 22 Nov 2009, Anders Carlsson wrote:
>> I know virtually nothing about the technical details, but on the Denial
>> web forum which you also frequent, there has been discussions over the
>> years about capacitors (?) going old inside the VIC and C64 too, causing
>> paddle jitter. Is this a factor you have considered, and perhaps have a
>> good fix for? Various solutions have been mentioned, but I can't recall
>> if anyone had the definite answer.
> The Neos/NCE mouse works with the VIC20.   This is because it uses the 
> POT line as right mouse button and a clocked protocol for data.
> It has the rather stupid feature that the left button blocks the 
> protocol though because FIRE is used both for the left button _and_ 
> the clock.
> Now, what I'd like to see would be a mouse converter supporting this 
> protocol but with both buttons wired to a POT line.   It could even be 
> made to include the buttons in the data protocol which is just 4-bits 
> of data per clock edge with a blanking period to reset the state.
> Such a setup would work for both the C64 and the VIC20.
> /Daniel
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Are there any protocol docs online?

I implemented a clocked data solution for PSXJoy, where I used "port 
knocking" to unlock the raw data feed, and then I'd use the fire button 
as CLK, and the 4 bits of direction as a nybble data path.  It worked 
quite well, and allowed two way, half duplex communication.  Bytes could 
be transferred in 40uS or so. sta CLK, lda data, sta tmp, stx CLK2, sta 
CLK, lda data, stx CLK2, asl, asl, asl, asl, ora tmp.  unlocking, 
reading, and locking took 80uS or so.

I'm eager to hear other ideas.


Jim Brain, Brain Innovations                                      (X) 
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times! 

       Message was sent through the cbm-hackers mailing list
Received on 2009-11-23 08:00:16

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