| Name | Address Port Value | Definition |
| Activate | 0x30 | For each logical device there is one activate register that controls whether or not the logical device is active on the ISA bus. Bit[0], if set, activates the logical device. Bits[7:1] are reserved and must return 0 on reads. This is a read/write register. Before a logical device is activated, I/O range check must be disabled. |
| I/O Range Check | 0x31 | This register is used to perform a conflict check on the I/O port range programmed for use by a logical device.
Bit[7:2] Reserved and must return 0 on reads Bit[1] Enable I/O Range check, if set then I/O Range Check is enabled. I/O range check is only valid when the logical device is inactive. Bit[0], if set, forces the logical device to respond to I/O reads of the logical device's assigned I/O range with a 0x55 when I/O range check is in operation. If clear, the logical device drives 0xAA. This register is read/write. |
| Logical Device Control Reserved | 0x32 - 0x37 | Reserved for future use |
| Logical Device Control Vendor Defined | 0x38 - 0x3F | Vendor defined registers |