LPC Interface Bridge Registers (D31:F0)
9-84
Intel
82801BA ICH2 Datasheet
9.10.3
GP_IO_SEL—GPIO Input/Output Select Register
Offset Address:
Default Value:
Lockable:
GPIOBASE +04h
0000FFFFh
No
Attribute:
Size:
Power Well:
R/W
32-bit
Resume
NOTES:
1.
There will be some delay on GPIO[24:28] going to their default state based on the rising edge of
RSMRST#. This is the case since these signals are in the resume well and resume well outputs
are not valid until after RSMRST# goes high. ICH2 only guarantees that these GPIOs will be
stable prior to SLP_S3# going active.
9.10.4
GP_LVL—GPIO Level for Input or Output Register
Offset Address:
Default Value:
Lockable:
GPIOBASE +0Ch
1B3F 0000h
No
Attribute:
Size:
Power Well:
R/W, RO
32-bit
See bit descriptions
Note:
Bits 5 and 2 are not implemented since GPIO[5,2] are not implemented.
Bit
Description
31:29, 26
Reserved.
28:27
25:24
GPIO[n] Select (GPIO[n]_SEL)
—R/W.
0 = Output. The corresponding GPIO signal is an output.
1 = Input. The corresponding GPIO signal is an input.
23:16
Always 0. The GPIOs are fixed as outputs.
15:0
Always 1. These GPIOs are fixed as inputs.
Bit
Description
31:29, 26
Reserved.
28:27,
25:24
GPIO Level (GP_LVL[n])—
R/W.
If GPIO[n] is programmed to be an output (via the
corresponding bit in the GP_IO_SEL register), then the bit can be updated by software to drive a
high or low value on the output pin. If GPIO[n] is programmed as an input, then software can read
the bit to determine the level on the corresponding input pin. These bits correspond to GPIO that
are in the Resume well, and will be reset to their default values by RSMRST# but not by
PCIRST#.
0 = Low
1 = High
23:16
GPIO Level GP_LVL[n]—
R/W.
These bits can be updated by software to drive a high or low
value on the output pin. These bits correspond to GPIO that are in the Core well, and will be reset
to their default values by PCIRST#.
0 = Low
1 = High
15:6, 4:3,
1:0
Reserved. For GPI[13:11] and [8:6,4:3,1:0], the active status of a GPI is read from the
corresponding bit in GPE1_STS register.
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