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Registers
1403
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Serial ATA (SATA) Controller
28.4.30 Port Serial ATA Active (SActive) Register (P0SACT)
The port serial ATA active (SActive) register (P0SACT) is used to indicate what command slots have
commands in them. The P0SACT is shown in
and described in
Figure 28-30. Port Serial ATA Active Register (P0SACT)
31
0
DS[
n
]
R/W1S-0
LEGEND: R/W = Read/Write; W1S = Write 1 to set; -
n
= value after reset
Table 28-34. Port Serial ATA Active Register (P0SACT) Field Description
Bit
Field
Value
Description
31-0
DS[
n
]
0-1
This field is bit significant. Each bit
n
corresponds to the TAG and command slot of a native queued
command, where bit 0 corresponds to TAG 0 and command slot 0. This bit field is set by software prior
to issuing a native queued command for a particular command slot. Prior to writing P0CI[TAG] to 1,
software sets DS[TAG] to 1 to indicate that a command with that TAG is outstanding. The device clears
bits in this bit field by sending a Set Device Bits FIS to the Port. The Port clears bits in this bit field that
are set to 1 in the SActive field of the Set Device Bits FIS. The Port only clears bits that correspond to
native queued commands that have completed successfully.
Software should only write to this bit field when P0CMD.ST bit is set to 1. This bit field is cleared when
P0CMD.ST is written from a 1 to a 0 by software. This bit field is not cleared by a Port reset
(COMRESET) or a software reset.
28.4.31 Port Command Issue Register (P0CI)
The port command issue register (P0CI) is used to indicate what that a command has been constructed
and may be carried out. The P0CI is shown in
and described in
.
Figure 28-31. Port Serial ATA Active (SActive) Register (P0SACT)
31
0
CI[
n
]
R/W1S-0
LEGEND: R/W = Read/Write; W1S = Write 1 to set; -
n
= value after reset
Table 28-35. Port Serial ATA Active (SActive) Register (P0SACT) Field Description
Bit
Field
Value
Description
31-0
CI[
n
]
0-1
Command Issued. This field is bit significant. Each bit
n
corresponds to a command slot, where bit 0
corresponds to command slot 0. This bit field is set by software to indicate to the Port that a command
has been built in system memory for a command slot and may be sent to the device. When the Port
receives a FIS that clears the BSY, DRQ, and ERR bits for the command, it clears the corresponding bit
n
in this register for that command slot. Bits in this field can only be set to 1 by software when
P0CMD.ST is set to 1.