Текст страницы
10.16 Serial ATA Optional Features
The following optional features are supported.
10.16.1 Asynchronous Signal Recovery
The device supports asynchronous signal recovery.
10.16.2 Device Power Connector Pin 11 Definition
The device supports Pin 11 of the power connector which may be used to provide the host with an activity indication
and disabling of staggered spin-up.
10.16.3 Phy Event Counters
Phy Event Counters are an optional feature to obtain more information about Phy level events that occur on the
interface. This information may aid designers and integrators in testing and evaluating the quality of the interface. A
device indicates whether it supports the Phy event counters feature in IDENTIFY DEVICE Word 76, bit 10. The host
determines the current values of Phy event counters by issuing the READ LOG EXT command with a log page of
11h (See Section 12.21.8). The counter values shall not be retained across power cycles. The counter values shall
be preserved across COMRESET and software resets.
The counters defined can be grouped into three basic categories: those that count events that occur during Data FIS
transfers, those that count events that occur during non-Data FIS transfers, and events that are unrelated to FIS
transfers. Counters related to events that occur during FIS transfers may count events related to host-to-device FIS
transfers, device-to-host FIS transfers, or bi-directional FIS transfers. A counter that records bi-directional events is
not required to be the sum of the counters that record the same events that occur on device-to-host FIS transfers and
host-to-device FIS transfers.
Implementations that support Phy event counters shall implement all mandatory counters and may support any of the
optional counters as shown in Table 146. Note that some counters may increment differently based on the speed at
which non-Data FIS retries are performed by the host and device. Implementations may record CRC and non-CRC
error events differently. For example, there is a strong likelihood that a disparity error may cause a CRC error. Thus,
the disparity error may cause both the event counter that records non-CRC events and the event counter that records
CRC events to be incremented for the same event. Another example implementation difference is how a missing
EOF event is recorded; a missing EOF primitive may imply a bad CRC even though the CRC on the FIS may be
correct. These examples illustrate that some Phy event counters are sensitive to the implementation of the counters
themselves, and thus these implementation sensitive counters cannot be used as an absolute measure of interface
quality between different implementations.
10.16.4
NCQ Non-Data (63h)
The NCQ Non-Data feature allows the host to manage the outstanding NCQ commands and/or affect the processing
of NCQ commands.
The NCQ Non-Data command is a non-data NCQ command. Only specified NCQ Non-Data subcommands are
executed as Immediate NCQ commands.
If NCQ is disabled and an NCQ Non-Data command is issued to the device, then the device aborts the command
with the ERR bit set to one in the Status register and the ABRT bit set to one in the Error register. This command is
prohibited for devices that implement the PACKET feature set. The queuing behavior of the device depends on which
subcommand is specified.
81
Hard Disk Drive Specification