1. Blocking and ghosting
only happen when you do an old-school keyboard hack of a
matrix encoder.
A keyboard hack also involves the "boot protocol" 6-button limitation.
There hasn't been a good reason to use a keyboard hack as a 2-player arcade encoder for
many, many years.
2. The keyboard encoder options commonly mentioned on BYOAC (I-Pac, KeyWiz, KADE,
Feb 2014 or newer X-Arcade, etc.) use dedicated inputs and do not use "boot protocol".
3. The MAME defaults, chosen back when keyboard hacks were the common interface choice, include "modifier" keys (Ctrl, Alt, Shift) since those don't count toward the "boot protocol" 6-button limit.
4. As mentioned earlier in the thread, these "modifier" keys can trigger undesired events. i.e. P1B2 (Alt) + P3B3 (Enter) = toggle between full-screen and window
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Bottom line to greatly reduce the odds of guests accidently nuking your MAME setup:
- Use a modern encoder. Friends don't let friends hack keyboards.
- Turn off sticky keys in Windows.
- Reprogram your encoder to remove "modifier" keys, mouse buttons, and TAB. (menu)
-- If your encoder uses shifted functions, be sure to change those too. i.e. I-Pac P1Start + P1Right = TAB
-- Use a keyboard if you need to get into the menu system.
- Change MAME defaults to work with the new encoder settings.
- Adjust FE settings as needed.
Scott