| Bits | Description |
|---|---|
| 7 | Enable F8 cpu speed hotkey and F5/F6 expansion bus hotkeys (soft reset = 1) |
| 6 | Divert BEEP only to internal speaker (hard reset = 0) |
| 5 | Enable F3 50/60 Hz hotkey (soft reset = 1) |
| 4 | Enable divmmc nmi by DRIVE button (hard reset = 0) |
| 3 | Enable multiface nmi by M1 button (hard reset = 0) |
| 2 | PS/2 mode (0 = keyboard primary, 1 = mouse primary; config mode only) |
| 1-0 | Audio chip mode (00 = YM, 01 = AY, 10 = ZXN-8950, 11 = Hold all AY in reset) |