> > > > MCFG_SCREEN_REFRESH_RATE( (XTAL_14MHz / 2) / (446 * 286) ) > > > > > > That's showing you how it's calculated: 7 MHz pixel clock divided by 446 > horizontal > > > pixels (including hblank) times 286 vertical scanlines (including vblank). > > > > It looks like it's integer arithmetic though, so it's only getting 54.0 instead of > > the proper 54.879. > > Good call. If you make it use FP math it does match the measured 54.87.
Or better yet, just convert it to raw params... and do twincobr.c while you're at it since it's got the exact same formula for refresh rate.
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Re: How to change refresh rate in MAME drivers?
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