Am Freitag, 13. Dezember 2019, 16:40:39 CET schrieb Jim Brain: > On 12/13/2019 9:21 AM, groepaz_at_gmx.net wrote: > > just to make it clear: its not the paddle (obviously, its just a resistor) > > - its the SID that imposes this limit. there is a capacitor that will > > charge in series with the resistor, and the SID counts how long that > > takes. > > > > the 512 cycles is also true for the VIC20. on the atari 800 the period is > > much longer (~20ms), the same is true for the Amiga. On the VCS *afaik* > > its even longer than that. > > Egad, typing on my phone is atrocious... Oh well, you got the idea. > Groepaz is more precise, it's not the paddles itself, but the circuitry > in the machine that takes the time. And, to add a bit more (on a real > keyboard, this time), it does not sample for 512 cycles. It clamps the > POT line to ground for 256 cycles to fully discharge the external > capacitor and then (if memory serves) allows the capacitor to charge for > 256 cycles, counting the number of cycles (of the 256) it takes to reach > some threshold. > > Folks will correct if I am imprecise again, but I do know there are two > states (the discharge state, the occurs for 256 cycles) and the sample > state (which also takes 256 cycles). thats correct :) interestingly, its different on the VIC20: the charging takes ~440µs and the clamping to GND takes ~65µs - thats why the 1531 mouse does not work with it -- http://hitmen.eu http://ar.pokefinder.org http://vice-emu.sourceforge.net http://magicdisk.untergrund.net well, if you cannot do _ANYTHING_ creative in the demoscene, you end up as diskmag writer and write about how good others are. <Maali>Received on 2020-05-29 23:55:27
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