5 Feb 2017, 08:24

I think i found why Mednafen PcEngine uses 232 lines.

The PcEngine can render several resolutions.
256x224 to 512x242, most commonly 256x239.
(here, timings in 1920 are welcome).

Mednaden render first line at 4 (0 to 239), the 4 first lines are ignored.
Mednaden render last line at 235 (0 to 239), the 4 last lines are ignored.
On a 240p (i think, 239 lines are useable on 240) game, 4 to 235 = 232 lines.

I think the first 4 lines and the last 4 lines are unused to show pixels because games never use them.

All that remains to verify.