> Ok, thanks for the explanation. > For example I Measured the Vsync of a Pyros oginal Toaplan at > 54.879 Hz, in MAME it's at 54.000000 Hz.looking at wardner.c > there is: > > 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).