Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 609

SATA Controller Registers (D31:F2)
Bit
12:8
7:5
4
3
2
1
0
Datasheet
Current Command Slot (CCS) — RO. Indicates the current command slot the PCH
is processing. This field is valid when the ST bit is set in this register, and is constantly
updated by the PCH. This field can be updated as soon as the PCH recognizes an
active command slot, or at some point soon after when it begins processing the
command.
This field is used by software to determine the current command issue location of the
PCH. In queued mode, software shall not use this field, as its value does not
represent the current command being executed. Software shall only use PxCI and
PxSACT when running queued commands.
Reserved
FIS Receive Enable (FRE) — R/W. When set, the PCH may post received FISes into
the FIS receive area pointed to by PxFB (ABAR+108h/188h/208h/288h) and PxFBU
(ABAR+10Ch/18Ch/20Ch/28Ch). When cleared, received FISes are not accepted by
the PCH, except for the first D2H (device-to-host) register FIS after the initialization
sequence.
System software must not set this bit until PxFB (PxFBU) have been programmed
with a valid pointer to the FIS receive area, and if software wishes to move the base,
this bit must first be cleared, and software must wait for the FR bit (bit 14) in this
register to be cleared.
Command List Override (CLO) — R/W. Setting this bit to 1 causes PxTFD.STS.BSY
and PxTFD.STS.DRQ to be cleared to 0. This allows a software reset to be transmitted
to the device regardless of whether the BSY and DRQ bits are still set in the
PxTFD.STS register. The Controller sets this bit to 0 when PxTFD.STS.BSY and
PxTFD.STS.DRQ have been cleared to 0. A write to this register with a value of 0 shall
have no effect.
This bit shall only be set to 1 immediately prior to setting the PxCMD.ST bit to 1 from
a previous value of 0. Setting this bit to 1 at any other time is not supported and will
result in indeterminate behavior. Software must wait for CLO to be cleared to 0 before
setting PxCMD.ST to 1.
Power On Device (POD) — RO. Cold presence detect not supported. Defaults to 1.
Spin-Up Device (SUD) — R/W / RO
This bit is R/W and defaults to 0 for systems that support staggered spin-up (R/W
when CAP.SSS (ABAR+00h:bit 27) is 1). Bit is RO 1 for systems that do not support
staggered spin-up (when CAP.SSS is 0).
0 = No action.
1 = On an edge detect from 0 to 1, the PCH starts a COMRESET initialization
sequence to the device.
Clearing this bit to 0 does not cause any OOB signal to be sent on the interface. When
this bit is cleared to 0 and PxSCTL.DET=0h, the Controller will enter listen mode.
Start (ST) — R/W. When set, the PCH may process the command list. When cleared,
the PCH may not process the command list. Whenever this bit is changed from a 0 to
a 1, the PCH starts processing the command list at entry 0. Whenever this bit is
changed from a 1 to a 0, the PxCI register is cleared by the PCH upon the PCH putting
the controller into an idle state.
Refer to section 10.3 of the Serial ATA AHCI Specification for important restrictions on
when ST can be set to 1 and cleared to 0.
Description
609