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Registers
1400
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Serial ATA (SATA) Controller
28.4.28 Port Serial ATA Control (SControl) Register (P0SCTL)
The port serial ATA control register (P0SCTL) is used by software to control SATA interface capabilities.
Writes to this register result in an action being taken by the Port PHY interface. Reads from the register
return the last value written to it. Reset on Global reset. These bits are static and should not be changed
frequently due to the clock crossing between the Transport and Link Layers. Software must wait for at
least seven periods of the slower clock (clk_asic or vbus clock) before changing this register. The P0SCTL
is shown in
and described in
Figure 28-28. Port Serial ATA Control Register (P0SCTL)
31
16
Reserved
R-0
15
12
11
8
7
4
3
0
Reserved
IPM
SPD
DET
R-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 28-32. Port Serial ATA Control Register (P0SCTL) Field Descriptions
Bit
Field
Value
Description
31-12
Reserved
0
Reserved.
11-8
IPM
0-Fh
Interface Power Management Transitions Allowed. Indicates which power states the Port PHY interface
is allowed to transition to. If an interface power management state is disabled, the Port does not initiate
that state and any request from the device to enter that state is rejected via PMNAKp.
0
No interface power management state restrictions.
1h
Transitions to the Partial state are disabled.
2h
Transitions to the Slumber state are disabled.
3h
Transitions to both Partial and Slumber states are disabled.
4h-Fh
Reserved
7-4
SPD
0-Fh
Speed Allowed. Indicates the highest allowable speed of the Port PHy interface.
Note: When host software must change this bit field value, the host must also reset the Port (DET = 1)
at the same time to ensure proper speed negotiation.
0
No speed negotiation restrictions.
1h
Limit speed negotiation to Generation 1 (1.5 Gbps) communication rate.
2h
Limit speed negotiation to Generation 2 (3 Gbps) communication rate.
3h-Fh
Reserved
3-0
DET
0-Fh
Device Detection Initialization. Controls the Ports device detection and interface initialization.
Note: This bit field may only be modified when P0CMD.ST = 0; changing this bit field while P0CMD.ST
= 1 results in undefined behavior. When P0CMD.ST is set to 1, this bit field should have a value of 0.
0
No device detection or initialization action is requested.
1h
Perform interface initialization sequence to establish communication. This results in the interface being
reset and communication re-initialized.
2h-3h
Reserved
4h
Disable the Serial ATA interface and put the Port PHY in offline mode.
5h-Fh
Reserved