> The overscan trick was, I think, first discovered by NOP and used in
> "Unknown Reality" at the title screen. Achieving the vertical overscan
> on the V9938/V9958 is actually quite simple. You only need two line
> interrupts (using r#19) and flip the LN bit (r#9 b7). The LN bit selects
> between a screen height of 192 lines and 212 lines.
> The first line interrupt needs to be at a line before line 192 and it
> should set the LN bit (screen height = 212 lines). The second line
> interrupt should be at a line beyond line 212 and clear the LN bit
> (screen height = 192 lines). This will somehow 'confuse' the VDP and it
> will keep on displaying skipping the black border in Y-direction
> alltogether.
Yesss!!!
Thanks! This is >>really<< cool!!!
(where is it used, in which demo etc?)
~Grauw
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