[Coco] Joystick jitter in OS9

[CoCoList for Color Computer Enthusiasts]

i believe this is true of most ad covertors...the lsm bit tends to bobble.
averaging (integrating) the last bit is good... it also allows for a slight
improvement in precission.

brett
 On May 12, 2014 11:18 PM, "CoCoList for Color Computer Enthusiasts" <
coco at maltedmedia.com> wrote:

> CoCoList for Color Computer Enthusiasts wrote:
>
>>
>> Got a question for you guys,
>> Does anyone know a good method of removing the "joystick jitter" in OS9
>> L2?
>> In certain postions, my (black Tandy) joystick or deluxe color mouse will
>> start "jumping" about 3 or 4 pixels, back and forth. It will occassionally
>> do this while trying to position it on an item.
>> I can loose some resolution, that's not an issue as I'm already skipping
>> about 6 or 7 pixels on a 640x192 screen to get full screen access. I do not
>> need "pixel by pixel" resolution.
>> I could possibly trim it to every 4 or 5 chars (8 pixels per char horiz,
>> 7 vert) if needed. It doesn't seem to jerk vertically. I haven't noticed if
>> it does this with the Hi-Res interface as I've had it disconnected lately.
>> This is not a major issue... it just "bugs" me.
>> I'm using C for programming and the mouse read is the standard mouse
>> packet system call.
>>
>> Anyone got any ideas?
>>
>>
>> Bill Pierce
>> "Today is a good day... I woke up" - Ritchie Havens
>>
>
> Bill,
>
> Unless you have tested your joystick with an ML routine in Basic and found
> there is no jitter, give some thought to the pots having deteriorated with
> age.
>
> I have some jitter with my deluxe joysticks and have found that that same
> jitter can be seen with an ohm meter. That means the routines that read the
> pots are not bad but the pots themselves are bad.
>
> If these pots are wire wound and not carbon tracks, you could try cleaning
> them with a deox spray. I can't tell by looking at them what type they are.
>
> About the only thing you can do via software is either calculate an
> average reading or do what Basic does. Basic will look at 10 readings and
> report the result when two match or if none match use the last reading.
>
> Robert
> robert.gault at att.net
>
>
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