Custom resolution question [FM Towns Marty]

[MK3FANATIC]

I'm using crt emudriver on windows10, radeon hd4550, I would like to know if it's possible to create a 2560x263 60Hz resolution. I edited one by the normal method, but it looks as expected 2560x263 55.654Hz. Does anyone know if this is possible? Or this information in groovymame that shows 2560x263 60Hz is wrong?     

[pakoman]

I think the maximum vertical resolution at 60hz progressive and 15.7khz is 244 or something around that.

If you want 263p at 60z you need to go beyond 15.7khz (and the screen to support it).

The FM Towns Marty most probably wouldn't be running at 15.7khz.

[Recapnation]

MAME doesn't report the right values for the FMT as it's not properly documented/measured, it seems. They likely saw that the framebuffer was capable of 263 lines at maximum in low-res mode and set that along with the 60.00 Hz for the vertical refresh they usually pick when it's unknown. The FMT could be used with standard tri-sync monitors (and 15.7 kHz modes) so those numbers are just wrong.

Like the X68, the system used many different modes, though. For progressive 15 kHz, apparently 256 * 240 and 320 * 240 were the most common res. modes, many times without using the full frame with the latter. So tell GM to use them instead and, in case, set also unevenstretchx in order to prevent any vertical scaling.


Edit: You're asking particularly about the Marty -- forget it as it's a dumbed-down console version for TV sets where interlace was everywhere and compatibility suffered a lot.

[psakhis]

With X68 Mame doesn't report 256 files (257 instead). My workaround is limiting on x68k.ini the crt_range

crt_range0 15625-15750, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 192, 256, 0, 0