Logical Device Configuration/Control
Registers [0x30-0xFF]
The INDEX PORT is used to select a specific
logical device register. These registers are then
accessed through the DATA PORT.
Used to access the registers that are assigned to
each logical unit. This chip supports seven logical
units and has seven sets of logical device
registers. The logical devices are Floppy, Parallel
Port, Serial Port 1 and Serial Port 2, Keyboard
Controller, Auxiliary I/O and ACPI. A separate set
(bank) of control and configuration register exists
for each logical device and is selected with the
Logical Device # Register (0x07).
The Logical Device registers are accessible only
when the device is in the Configuration State. The
logical register addresses are:
Logical Device Registers
TABLE 64 - LOGICAL DEVICE REGISTERS
LOGICAL DEVICE
REGISTER
ADDRESS
DESCRIPTION
STATE
Activate Note1
(0x30)
Bits[7:1] Reserved, set to zero.
Bit[0]
C
Default = 0x00
= 1
Activates the logical device currently
selected through the Logical Device #
register.
Logical device currently selected is inactive
on Vcc POR or
Reset_Drv Note 2
= 0
Logical Device Control (0x31-0x37) Reserved - Writes are ignored, reads return 0.
C
C
Logical Device Control (0x38-0x3f) Vendor Defined - Reserved - Writes are ignored,
reads return 0.
Mem Base Addr
I/O Base Addr.
(0x40-0x5F) Reserved - Writes are ignored, reads return 0.
C
C
(0x60-0x6F) Registers 0x60 and 0x61 set the base address for the
device. If more than one base address is required,
0x60,2,... = the second base address is set by registers 0x62 and
addr[15:8] 0x63.
(see Device Base I/O
Address Table)
Refer to - I/O Base Address Configuration Register
Description - for the number of base address
registers used by each device.
Default = 0x00
0x61,3,... =
addr[7:0]
on Vcc POR or
Reset_Drv
Unused registers will ignore writes and return zero
when read.
Interrupt Select
(0x70,072) 0x70 is implemented for each logical device. Refer to
Interrupt Configuration Register description. Only the
keyboard controller uses Interrupt Select register
0x72. Unused register (0x72) will ignore writes and
return zero when read. Interrupts default to edge high
(ISA compatible).
C
Defaults :
0x70 = 0x00,
on Vcc POR or
Reset_Drv
0x72 = 0x00,
on Vcc POR or
Reset_Drv
169
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