5200 trackball sampling rate

[8bitAndy]

The way I understand the trackball workings is that the speed you roll it produces a variable resistance on the joystick wires. My question is how long of a period the movement is sampled.

 

For example, if the ball is moved quickly for 1/200th of a second and then stopped, does the resistance remain high (or low) longer to make sure the game has enough time to sample it?

[TGB1718]

I believe trackballs use optical sensors to detect the motion of a "spoked" wheel which is driven

by the trackball motion, one detects up/down and the other left right.

 

This is presented to the joystick port as high and low switching signals.

 

The direction is detected by which of 2 signals in each direction is presented first and the speed by how

fast the signals change with time. 

 

I don't know the pin connections, but for example if you move up, you will get pin 1 high/low before pin 2

on the joystick port, if you move down pin 2 will go high/low before pin 1. Same happens on pins 3 and 4 

for left/right movement.

 

It's the software reading these signals that dictates how the game reacts to these signals.

 

 

 

[vitoco]

1 hour ago, TGB1718 said:

I believe trackballs use optical sensors to detect the motion of a "spoked" wheel which is driven

by the trackball motion, one detects up/down and the other left right.

That's how both versions of CX22 trackball and the ST mouse work (digital), but the 5200 trackball is a different (analog) beast.

 

[TGB1718]

16 hours ago, vitoco said:

That's how both versions of CX22 trackball and the ST mouse work (digital), but the 5200 trackball is a different (analog) beast.

Thanks, I didn't know that 

[Danjovic]

5200 trackball operates by converting the mouse speed into current that makes the timing capacitor cahrges at different rates. 

Unfortunately the service manual brings no information about the range  of the data rate, but it should be possible to replicate the output stage with a microcontroller and perform some experiments.