Some notes about the new composite sync feature- Just like any other feature, composite sync support can be enabled independently for boot time (BIOS mod with ATOM-15) and for Windows (with VMMaker).
- In order to enable composite sync right from boot, you have to check the corresponding option in ATOM-15 and flash your video card with the modified BIOS. Composite sync will be applied to all available outputs, so that's something you may need to consider depending on your setup.
- Regarding Windows, first of all, an important warning: enabling composite sync may be a tricky business. Even if you know what you're doing chances are you get into a messed video state at some point of the process. Once you get everything right it should work fine forever, you just need to get there. I recommend to always work with two monitors during the process and only enable composite sync to the secondary monitor (the one you're not working with) so in case anything goes wrong you don't get an unusable display. If anything went wrong and you can't find your way around a messed display, you can boot in same mode and uninstall the driver.
- There's a new button in VMMaker's video card tab that allows you to toggle composite sync for the currently selected output.
- Again, HD 5000+ cards are easier to setup for composite sync than legacy ones. Just enable composite sync for the selected output, create the modes and you're done.
- Legacy (pre HD 5000 cards) need some extra steps in order to get correct composite sync:
- First, to get consistent composite sync behaviour for legacy cards you must update CRT Emudriver (based on 12.6) to the new beta 12 version (this is not required for HD 5000+ cards).
- You must set both H and V sync polarities to positive for all modes. So after enabling composite sync, you must generate and install all modes again, but first you need to go to the monitor tab to edit your selected monitor preset and modify it with the proper polarities, e.g.:
monitor "arcade_15", "Arcade 15.7 kHz - standard resolution", "4:3"
crt_range0 15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 1, 1, 192, 288, 448, 576
- Finally, still in VMMaker make sure to mark "Export settings to GroovyMAME" in MAME's tab so the correct polarities are used by GroovyMAME.
- If you're using an VGA to BNC cable, remind that composite sync is ouput through the h-sync cable, so if you're using a T connector, unplug the v-sync cable.