Posted By
MMS
on 2024-10-28
19:54:03
 |  Re: Joystick Pinout descriptions - LightPen ?
Oh Guys, you are really the source of wisdom! Thank you! As the other one looks fake (not lightpen) I will do my version. Surely I have some empty pens around 
So it is clearly different from the C64 connection (need 4,5,6,7 pins to be connected), so C64 ones cannot be used, similar to 1531 mouse and paddles :-(
And those two VIC-II registers, really well suits the task.
But the process Crown explained is crazy complex and should be painfully slow, so NOW I understand the speed I saw on George's video. Sure, it won't replace the mouse
My naive expactation (based on SVS Ultimate map), you set $FF0A Bit 2 for Lightpen IRQ, and when the raster line activated the sensor of the pen, you have get an IRQ, and you get the rasterline where the pen activated in $FF0b. I did not have the smallest idea on x coordinates . Silly me!
BTW C128 BASIC 7.0 has the command PEN, specifically created for this task, but with those VIC-II registres this is a pretty straingforward register reading task.
Octasoft BASIC 7.0 knows the token but did not realized the function/command.
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