JP4435260B2 - Electronic equipment with serial ATA interface - Google Patents

Description

  The present invention relates to an electronic device having a serial ATA (AT Attachment) interface, and more particularly to an electronic device typified by a disk drive suitable for power saving of a serial ATA bus conforming to the serial ATA interface standard.

  Currently, a standard for the serial ATA interface, which is a new interface for disk drives, is being formulated. The serial ATA interface is used as an interface between a peripheral device represented by a magnetic disk drive and a host system (host) in the same manner as a conventional ATA interface (that is, a parallel ATA interface).

  A peripheral device having a serial ATA interface, for example, a magnetic disk drive (hereinafter referred to as HDD) is connected to the host via a serial ATA bus. In such an HDD, it is necessary to convert the conventional ATA interface into a serial ATA interface and the serial ATA interface into a conventional ATA interface in order to ensure compatibility with the conventional ATA interface. Such interface conversion is performed by, for example, an LSI (bridge LSI) called a serial ATA bridge.

  In the serial ATA standard, three layers, that is, a PHY (Physical Layer) layer (physical layer), a LINK layer (link layer), and a transport layer are defined for each function. The PHY layer is a part having a function of executing high-speed signal transmission / reception, interprets the received content and transmits it to the LINK layer, and outputs a signal in response to a request from the LINK layer. The LINK layer issues a signal output request to the PHY layer according to the request content from the transport layer (transport layer), and transmits the reception input from the PHY layer to the transport layer. The Transport layer performs conversion to the operation in the conventional ATA standard. The role of the transport layer corresponds to a portion that outputs the ATA signal on the host side when the bridge LSI is used in the magnetic disk drive, as compared with the case of the conventional ATA connection. The bridge LSI and the disk controller (HDC) in the HDD are connected by an ATA bus (or a bus conforming thereto) conforming to the conventional ATA interface standard. Therefore, the connection portion between the bridge LSI and the HDC in the HDD operates equivalent to or equivalent to the conventional ATA interface standard. As described above, in the serial ATA interface, a protocol such as a logical command is compatible with the conventional ATA standard, while a portion connected in parallel in the past is converted into a serial signal.

  In the serial ATA interface, in addition to the power saving state (mode) based on the standard of the conventional ATA interface (that is, the parallel ATA interface), the power saving is performed for the serial ATA bus itself that connects the peripheral device and the host. Is defined. The concept of saving the power of the serial ATA bus itself does not exist in the conventional ATA standard.

  In the serial ATA interface standard, three types of power management modes of the serial ATA interface are defined: “PHY READY (IDLE)”, “PARTIAL (partial)”, and “SLUMBER (slumber)”. In “PHY READY” mode, the circuit that realizes the operation of the PHY layer (PHY circuit) and the main PLL (Phase-Locked Loop) circuit operate, and the interface states of the host side and the peripheral device side are synchronized. The state that is. “PARTIAL” and “SLUMBER” modes are states in which the PHY circuit is operating but the interface signal is neutral.

  The difference in definition between the “PARIAL” and “SLUMBER” modes is the return time from these modes to the “PHY READY (IDLE)” mode. That is, in the “PARIAL” mode, it is defined that the return time from the mode should not exceed 10 μs. On the other hand, in the “SLUMBER” mode, it is defined that the return time from the mode should not exceed 10 ms. In which part of the device the power saving function is to be operated in the “PARIAL” or “SLUMBER” mode (that is, which circuit power is cut off) as long as the recovery time and the power status of the interface are observed. It can be arbitrarily defined by the manufacturer.

  The transition to the power save (that is, ATA power save) state based on the conventional ATA interface standard is basically realized by the host side. As the ATA power save state, “IDLE (idle)”, “STANDBY (standby)”, “SLEEP (sleep)”, and the like are defined. On the other hand, the transition to the power saving state of the serial ATA bus itself (ie, serial ATA power saving) (“PARIAL” or “SLUMBER”) conforming to the serial ATA interface standard can be made on either the host side or the peripheral device side. It may be realized by initiative. However, regarding the technology for controlling the status of the serial ATA power save (particularly the technology for linking the status of the serial ATA power save to the status of the ATA power save), the standard of the serial ATA interface is being formulated. Is not known and there is no literature.

  As described above, when the serial ATA interface is applied to the HDD interface and the HDD is connected to the host via the serial ATA bus, the HDD includes a serial ATA interface control circuit circuit that converts the conventional ATA interface into a serial ATA interface. (Serial ATA bridge) must be provided. In such an HDD, the operation of the connection portion between the serial ATA interface control circuit and the disk controller (HDC) of the HDD is equivalent to or equivalent to the conventional ATA interface standard. Therefore, the disk controller recognizes the serial ATA bridge as if it is a host that issues an instruction. Therefore, the operation of the HDD except the periphery of the serial ATA bridge is the same as that of the conventional HDD. In an HDD to which this serial ATA interface is applied, a conventional ATA bus for connecting a serial ATA interface control circuit and a disk controller (HDC) can be realized on a printed wiring board (PCB) in the HDD. The bus wiring length is shortened. For this reason, an HDD to which a serial ATA interface is applied is expected to improve the data transfer speed, which was difficult to realize with a conventional ATA bus.

  The serial ATA interface is a standard that has been studied on the assumption that compatibility with the conventional ATA standard is ensured. For this reason, in order to realize a new power saving concept defined by the serial ATA interface, it is necessary to provide a new means on the host side for instructing to that effect. However, there is a risk of deviating from the conventional ATA standard by applying new means. In particular, providing new means on the host side has a great influence on the entire system.

  The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an electronic device having a serial ATA interface that can effectively reduce the power consumption by effectively utilizing the power saving function of the serial ATA bus defined by the serial ATA standard. Is to provide.

  According to one aspect of the present invention, an electronic device having a serial ATA interface is provided. The electronic device includes means for detecting issuance or reception of a predetermined command, means for confirming completion of execution of a command detected by the detection means, and serial ATA according to confirmation of command execution completion by the confirmation means. And a means for performing control for shifting to the power saving mode of the interface.

  In the electronic device having such a configuration, when the issuance or reception of a predetermined command is detected, the power of the serial ATA interface (serial ATA bus) is confirmed in response to the completion of execution of the command. Transition to save mode is controlled. As a result, if a command that takes a long time to return to the read / write mode, such as a sleep command that is a power save command of the ATA interface, is defined as the predetermined command, When issuance or reception is detected, the serial ATA bus is also shifted to the power save mode. As a result, power consumption can be reduced. That is, according to the present invention, the power saving function of the serial ATA bus defined by the serial ATA standard can be effectively utilized while maintaining compatibility with the conventional ATA standard, thereby reducing power consumption.

  Here, the shift control of the serial ATA interface to the power save mode can be autonomously performed by a serial ATA interface control circuit that performs interface conversion between the serial ATA interface and the ATA interface. For this reason, the serial ATA interface control circuit measures a predetermined time each time the system shifts to the idle mode of the serial ATA interface in response to reception of the following means, that is, a command subject to interface conversion. It is preferable to provide a measuring means for starting measurement and a means for shifting to a predetermined power save mode of the serial ATA interface when a new command is not received even when the predetermined time is measured by the measuring means. .

  When the electronic device is a disk drive connected to the host via a serial ATA bus, the following means, that is, the execution completion of the command from the host, is sent to the issuer of the command. It is preferable to provide means for reporting and means for performing control to shift to the power saving mode of the serial ATA interface after the completion of execution of a predetermined command by the reporting means. Also, if the ATA interface power save command is defined as a predetermined command, the serial ATA bus power save function defined in the serial ATA standard maintains compatibility with the conventional ATA standard. However, it can be effectively utilized to reduce the power consumption of the disk drive. Therefore, the operating time of a host using the disk drive as a storage device, for example, a notebook personal computer driven by a battery, can be extended.

  When a transition is made immediately to the power saving mode of the serial ATA interface after the completion of execution of the predetermined command, a read / write mode in which a read / write command can be executed if a command is issued from the host immediately after the transition. It takes time to return (transition) to (active mode). For example, a check power mode command used to inquire the disk drive whether the spindle motor has completely stopped is likely to be issued immediately after the completion of execution of the ATA interface power save command. Therefore, after the command execution completion report, it is preferable to wait for the time determined from the command reception frequency from the host to elapse and shift to the power saving mode of the serial ATA interface. The reception frequency may be calculated from a series of command reception times indicated by the reception time information stored in the storage unit by storing the reception time information indicating the reception time of the command from the host.

  Further, in order to be able to shift to the power saving mode of the serial ATA interface, it is necessary to support the power saving function of the serial ATA interface not only on the disk drive side but also on the host side. Therefore, a means for determining whether or not the host side supports the power saving function of the serial ATA interface based on the result of the shift control to the power saving mode of the serial ATA interface by the control means. And a means for storing flag information indicating the determination result by the determination means, and when the host information indicates that the host side does not support the power saving function of the serial ATA interface, the serial ATA interface It is preferable to adopt a configuration in which the shift control to the power save mode is suppressed. In such a configuration, even when the host side does not support the power saving function of the serial ATA interface, the transition control from the disk drive side to the power saving mode of the serial ATA interface is prevented. it can. Thus, it is possible to keep the serial ATA bus in a stable state without causing unnecessary state transition in the serial ATA bus.

  According to the present invention, when it is detected that a predetermined command is issued or received, when the completion of execution of the command is confirmed, the serial ATA interface (serial ATA bus) enters the power save mode. By adopting a configuration in which the transition is controlled, the power saving function of the serial ATA bus defined by the serial ATA standard can be effectively used to reduce power consumption.

1 is a block diagram showing a configuration of a system including a magnetic disk drive (HDD) 10 according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of an HDD main body 11 included in the HDD 10 in FIG. 1. The figure which shows the state transition of the ATA power save mode applied in the embodiment. FIG. 4 is a diagram illustrating a correspondence relationship between each ATA power save mode in FIG. 3 and a power-off state of each circuit in the HDD main body 11 in each ATA power save mode. FIG. 4 is a diagram illustrating an example of a time required for returning from each ATA power save mode (M1 to M5) in FIG. 3 to a read / write mode M0. The figure which shows the relationship between each ATA power save mode in FIG. 3, and SATA power save mode set when HDD10 is set to the said mode. 6 is a flowchart showing a procedure of power control performed when a command from the host 20 is received in the HDD main body 11 in the HDD 10. The figure which shows the state transition of the SATA power save mode applied in the modification of the embodiment.

  Hereinafter, an embodiment in which the present invention is applied to a system including a magnetic disk drive having a serial ATA interface (hereinafter referred to as a SATA interface) will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a system including a magnetic disk drive (hereinafter referred to as HDD) 10 according to an embodiment of the present invention. The HDD 10 includes a SATA interface control circuit 12 in addition to the HDD main body 11 that is a conventionally known HDD configuration that performs parallel data transfer using an ATA interface. The SATA interface control circuit 12 is connected to the HDD main body 11 via an ATA bus (parallel ATA bus) 13 and is connected to a host (host system) 20 via a SATA bus (serial ATA bus) 30. SATA bridge. The SATA interface control circuit 12 is, for example, a one-chip LSI (Large Scale Integrated Circuit) that performs interface conversion between the ATA interface and the SATA interface. In particular, the SATA interface control circuit 12 has a function of converting an instruction given via the SATA bus 30 into a signal rule of the ATA bus 13 (ATA interface) and transmitting the signal rule to the HDD main body 11 via the ATA bus 13.

  The host 20 is an electronic device that uses the HDD 10 as a storage device, and is a personal computer, for example. The host 20 includes a SATA interface control circuit 22 in addition to a host body 21 that is a host configuration that performs parallel data transfer using an ATA interface, which is conventionally known. The SATA interface control circuit 22 is connected to the host main body 21 via the ATA bus (parallel ATA bus) 23 and is connected to the HDD 10 via the SATA bus (serial ATA bus) 30 and is connected to the host 10 via the ATA bus. It is a bridge. Similar to the SATA interface control circuit 12 in the HDD 10, the SATA interface control circuit 22 is a one-chip LSI that performs interface conversion between the ATA interface and the SATA interface. In particular, the SATA interface control circuit 22 has a function of converting an instruction given via the ATA bus 23 on the host 20 side into a signal rule of the SATA bus 30 (SATA interface) and transmitting the signal to the HDD 10 via the SATA bus 30. Have.

  The SATA interface control circuits 12 and 22 include physical layer processing units 121 and 221 and link / transport layer processing units 122 and 222, respectively. The physical layer processing units 121 and 221 have a function of executing high-speed serial data transfer (transmission / reception) via the SATA bus 30. The data transfer rate here is 1.5 Gbps (gigabit / second). The physical layer processing units 121 and 221 interpret the contents received from the SATA bus 30 and transmit them to the link / transport layer processing units 122 and 222 (the link layer processing units therein). The physical layer processing units 121 and 221 output (transmit) serial data signals in response to requests from the link / transport layer processing units 122 and 222 (the link layer processing units therein). The link / transport layer processing units 122 and 222 include a link layer processing unit and a transport layer processing unit (not shown). The link layer processing unit issues a signal output request to the physical layer processing units 121 and 221 in accordance with the request content from the transport layer processing unit, and receives the received input from the physical layer processing units 121 and 221 as transport layer processing. To the department. The transport layer processing unit performs interface conversion between the ATA interface and the SATA interface.

  In place of the ATA buses 13 and 23, a bus conforming to the ATA bus, for example, a PCI bus (Peripheral Component Interconnect Bus) may be used. In this case, it is possible to provide the SATA interface control circuits 12 and 22 (which constitute the SATA bridge) in the PCI bridge. In addition, the SATA interface control circuits 12 and 22 (which constitute the SATA bridge) may have a function of transmitting and receiving a serial ATA interface signal to and from the SATA bus 30.

  FIG. 2 is a block diagram showing a configuration of the HDD main body 11 in FIG. The HDD main body 11 includes a disk 111 as a recording medium. At least one of the two disk surfaces of the disk 111 is a recording surface on which data is magnetically recorded. A head (magnetic head) 112 is disposed corresponding to one of the disk surfaces of the disk 111 that forms this recording surface. 1 shows an example of the HDD 10 having one head 112 for the sake of drawing. However, generally, the two disk surfaces of the disk 111 form a recording surface, and a head is arranged corresponding to each disk surface. In the configuration of FIG. 1, an HDD 10 including a single disk 111 is assumed. However, it may be an HDD in which a plurality of disks 111 are stacked.

  The disk 111 is rotated at high speed by a spindle motor (hereinafter referred to as SPM) 113. The head 112 is used for data writing (data recording) to the disk 111 and data reading (data reproduction) from the disk 111. The head 112 is attached to the tip of the actuator 114. The actuator 114 has a voice coil motor (hereinafter referred to as VCM) 115 that is a drive source of the actuator 114. The actuator 114 is driven by the VCM 115 to move the head 112 in the radial direction of the disk 111. As a result, the head 112 is positioned on the target track. The SPM 113 and the VCM 115 are driven by drive currents (SPM current and VCM current) supplied from the motor driver IC 116, respectively. The motor driver IC 116 supplies an amount of SPM current designated by the CPU 121 to the SPM 113. Also, the motor driver IC 116 supplies the VCM current specified by the CPU 121 to the VCM 115.

  The head 112 is connected to a head IC (head amplifier circuit) 117. The head IC 117 includes a read amplifier that amplifies a read signal read by the head 112 and a write amplifier that converts write data into a write current. The head IC 117 is connected to a read / write IC (read / write channel) 118. The read / write IC 118 is a signal processing device that executes various signal processing such as A / D (analog / digital) conversion processing, read data encoding processing, and read data decoding processing for a read signal. The read / write IC 118 is connected to a disk controller (hereinafter referred to as HDC) 119.

  The HDC 119 has a disk control function for controlling data transfer between the HDC 119 and the disk 111. The HDC 119 also has an ATA interface. That is, the HDC 119 has an ATA interface control function for transmitting and receiving commands (read / write commands, etc.) and data to and from the host 20 via the ATA bus 13. However, in the present embodiment in which the HDD 10 has the SATA interface, the HDC 119 is connected to the SATA interface control circuit 12 via the ATA bus 13 unlike the conventional HDD, and the SATA interface control circuit 12 and the SATA bus 30 are connected. Via the host 20. The HDC 119 also has a buffer control function for controlling the buffer RAM 120. The HDC 119 includes a status register 119 a for notifying the host 20 of the state of the HDD 10.

  A part of the storage area of the buffer RAM 120 is used as an area for a data buffer that temporarily stores data transferred between the host 20 and the HDC 119 in the HDD 10. Another part of the storage area of the buffer RAM 120 is used for a flag storage area 120a for storing a SATA power save disable flag F, which will be described later, and a command reception time storage area 120b for storing time information indicating the reception time of a received command. It is done. The command reception time storage area 120b is used as a ring buffer for storing reception time information of the latest fixed number of reception commands.

  The CPU 130 has a nonvolatile memory (not shown) in which a control program is stored in advance (for example, a flash ROM that is a rewritable nonvolatile memory). The CPU 130 controls each part in the HDD 10 according to a control program stored in the nonvolatile memory. In particular, when the command from the host 20 received by the HDC 119 is a specific command (ATA power save command) for designating a power save mode (hereinafter referred to as ATA power save mode) of the ATA interface, the CPU 130 determines that the HDD 10 Set to the ATA power save mode specified in. Further, when setting the ATA power save mode, the CPU 130 causes the SATA interface control circuit 12 to set the SATA power save mode associated with the mode in advance via the HDC 119 and the ATA bus 13.

  FIG. 3 is a diagram showing state transitions in the ATA power save mode (power save state compliant with the ATA interface standard) applied in the present embodiment. In this embodiment, five types of ATA power save modes are prepared: an active / idle mode M1, a performance / idle mode M2, a low power / idle mode M3, a standby mode M4, and a sleep mode M5. In addition to these power saving modes M1 to M5, a read / write mode (active mode) M0 capable of executing a read / write command is prepared as an ATA interface mode. Here, the power consumption decreases in the order of read / write mode M0 → active / idle mode M1 → performance / idle mode M2 → low power / idle mode M3 → standby mode M4 → sleep mode M5.

  When the execution of the read / write according to the read / write command in the read / write mode M0 is completed in the HDD 10 (the HDD main body 11), the active / idle mode is controlled by the CPU 130 in order to save power consumption in the HDD 10 Transition to M1. If a new command is not sent from the host 20 even after a certain time T1 has elapsed after the transition to the active / idle mode M1, the CPU 130 controls the CPU 10 to further save power consumption. It is automatically changed to the performance / idle mode M2. Modes M1 and M2 are ATA power save modes arbitrarily defined by the manufacturer.

  If a new command is not sent from the host 20 even after a certain time T2 has elapsed after the transition to the performance / idle mode M2, the CPU 130 controls the CPU 10 to further save power consumption. A transition is made to the low power / idle mode M3. This mode M3 corresponds to “IDLE (idle)” of the ATA interface standard. Therefore, when an idle command is sent from the host 20 in each of the modes M1 and M2, the ATA power save mode of the HDD 10 is shifted to the low power / idle mode M3 according to the command. Similarly, when a standby command is sent from the host 20 in each of the modes M1, M2, and M3, the ATA power save mode of the HDD 10 is changed to the standby mode M4 according to the command. As a kind of standby command, a standby immediate command that can specify a time until transition to the standby mode is known. In the case of the standby-immediate command, a transition is made to the standby mode M4 after the time specified by the command. When a sleep command is sent from the host 20 in each of the modes M1, M2, M3, and M4, the ATA power save mode of the HDD 10 is changed to the sleep mode M5 according to the command. When a read / write command is sent from the host 20 in each of the modes M1, M2, M3, M4, and M5, the ATA power save mode of the HDD 10 is changed to the read / write mode M0 according to the command.

  FIG. 4 shows a correspondence relationship between the respective modes M0 to M5 and the power OFF state of each circuit in the HDD main body 11 in the modes M0 to M5. In the read / write mode M0, power is supplied to each circuit in the HDD body 11 so that the HDD body 11 can immediately execute a read / write operation. In each idle mode of the active / idle mode M1, the performance / idle mode M2, and the low power / idle mode M3, the power supply to some circuits in the HDD main body 11 is cut off (OFF). In the active / idle mode M1, the disk 111 is rotated by the SPM 113, and the head 112 is positioned on a certain track on the disk 111 by servo control. In the performance / idle mode M2, the disk 111 is rotated by the SPM 113, and the head 112 exists on an arbitrary track on the disk 111 without servo control. In the low power / idle mode M 3, the disk 111 is rotated by the SPM 113, but the head 112 is moved to a retracted position that is out of the disk 111. Therefore, in the active / idle mode M1, only power supply to some circuits (write channels) in the read / write IC 118 is cut off. On the other hand, in the performance / idle mode M 2, power supply to some circuits (VCM driver) in the motor driver IC 116 and some circuits in the read / write IC 118 is cut off. In the low power / idle mode M3, power supply to some circuits in the motor driver IC 116 is cut off, and power supply to the head IC 117 and the read / write IC 118 is cut off. The time until returning to the read / write mode M0 (that is, the return time until the read / write can be executed again) differs depending on each of the above idle modes. The active / idle mode M1 → the performance / idle mode M2 → low It becomes longer in the order of the power / idle mode M3. The power consumption required in each of the idle modes becomes smaller in the order of the active / idle mode M1, the performance / idle mode M2, and the low-power / idle mode M3.

  In the standby mode M4, the rotation of the SPM 113 is stopped. Here, power supply to the SPM 113, the motor driver IC 116, the head IC 117, the read / write IC 118, and the buffer RAM 120 is cut off. For this reason, the power consumption in the standby mode M4 is smaller than that in the low power / idle mode M3, and on the contrary, the recovery time becomes longer.

  In the sleep mode M5, power is supplied only to a part of the circuits (reset processing circuit) in the HDC 119, and power supply to most circuits is cut off. Here, the return to the read / write mode M0 can be performed only by the reset operation, and the return time is approximately the same as the case of returning from the standby mode M4. The power consumption in the sleep mode M5 is the smallest among the above modes M0 to M5.

  FIG. 5 shows an example of the time required to return from the above modes M1 to M5 to the read / write mode M0.

  FIG. 6 shows the relationship between the modes M0 to M5 and the SATA power save mode set by the control of the CPU 130 in the HDD 10 when the HDD 10 is set to the modes M0 to M5. In the example of FIG. 6, when the ATA power save mode (ATA interface mode) is the read / write mode M0, the SATA power save mode (SATA interface mode) is set to the idle mode M11. When the ATA power save mode is the active / idle mode M1 or the performance / idle mode M2, the SATA power save mode is set to the partial mode M12. However, since the performance / idle mode M2 transitions only from the active / idle mode M1, the partial mode M12 is continued at the transition to the performance / idle mode M2. When the ATA power save mode is the low power / idle mode M3, the standby mode M4, or the sleep mode M5, the SATA power save mode is set to the slumber mode M13.

  Next, operations in the system of FIG. 1 will be described with reference to the flowchart of FIG. 7 by taking as an example power control performed when a command from the host 20 is received in the HDD main body 11 in the HDD 10.

  Assume that a command addressed to the HDD 10 compliant with the ATA interface standard is sent from the host body 21 of the host 20 to the ATA bus 23. The command on the ATA bus 23 is received by the SATA interface control circuit 22 of the host 20. The link / transport layer processing unit 222 of the SATA interface control circuit 22 converts the received command into a command compliant with the SATA interface standard (signal rule of the SATA bus 30) and sends it to the SATA bus 30. The command on the SATA bus 30 is received by the SATA interface control circuit 12 of the HDD 10. The link / transport layer processing unit 122 of the SATA interface control circuit 12 converts the received command into a command (signal rule of the ATA bus 13) compliant with the ATA interface standard, and sends the command to the ATA bus 13. The command on the ATA bus 13 is received by the HDC 119 provided in the HDD main body 11 of the HDD 10. From the HDC 119, the SATA interface control circuit 12 is recognized as a host. The command received by the HDC 119 is passed to the CPU 130.

  When receiving the command passed from the HDC 119, the CPU 130 stores command reception time information indicating the reception time of the command in the command reception time storage area 120b in the buffer RAM 120 (step S1). Next, CPU 130 determines whether or not the received command is one of predetermined commands (step S2). Here, the predetermined commands are commands related to power saving, and are an idle command, a standby command, and a sleep command.

  When the received command is one of predetermined commands, the CPU 130 executes the process described below. First, the CPU 130 interprets the received command and executes an operation instructed by the command (step S3). That is, when the received command is an idle command, the CPU 130 transitions the ATA power save mode of the HDD 10 to the low power / idle mode M3. If the received command is a standby command, the CPU 130 changes the ATA power save mode of the HDD 10 to the standby mode M4. When the received command is a sleep command, the CPU 130 causes the ATA power save mode of the HDD 10 to transition to the sleep mode M5.

  When CPU 130 finishes executing the received command and confirms the completion of execution of the command, CPU 130 performs processing for reporting the completion of execution of the command to host 20 (step S4). That is, the CPU 130 sets a response status indicating completion of command execution in the status register 119 a and sends an interrupt signal to the ATA bus 13. The SATA interface control circuit 12 reads the contents of the status register 119a in the HDC 119 in response to this interrupt signal. The SATA interface control circuit 12 sends a command execution completion report based on the SATA interface standard to the host 20 via the SATA bus 30 based on the contents of the read status register 119a. When receiving the command execution completion report on the SATA bus 30, the SATA interface control circuit 22 in the host 20 sends an interrupt signal to the host main body 21 via the ATA bus 23. The host body 21 receives a command execution completion report (command completion response) from the SATA interface control circuit 22 in response to the interrupt signal.

  In this embodiment, when the command sent from the host 20 to the HDD 10 is one of predetermined commands, that is, commands related to power saving, the CPU 130 instructs the SATA interface control circuit 12 to perform SATA power saving. Mode control (that is, power control of the ATA bus 13) is executed. Here, in the case of an idle command, a standby command, or a sleep command, all are controlled to transition to the slumber mode M13.

  The control of the SATA power save mode by the CPU 130 is performed by using a link / transport layer processing unit of the SATA interface control circuit 12 via the ATA bus 13 for primitives in which a signal pattern specifying the SATA power save mode conforming to the SATA interface standard is set. 122 (link processing unit included in) is transmitted. Note that a control register for controlling the SATA power save mode may be provided in the SATA interface control circuit 12, and the SATA bus 30 may be shifted to the target SATA power save mode by controlling the register from the CPU.

  In the present embodiment, for the reason described below, a configuration in which a transition to a corresponding SATA power save mode is immediately performed after a command execution completion report (command completion response) related to ATA power save is not applied. First, when the SATA bus 30 is immediately shifted to the slumber mode M13 after the command execution completion report, a recovery time of a maximum of 10 ms is required for a command response from the definition of the slumber mode M13. Here, it is assumed that the host 20 issues a standby command, for example, a standby immediate command, to the HDD 10 and then uses the check power mode command to reliably monitor the stop of the SPM 113 in the HDD 10. In this case, if the SATA power save mode immediately shifts to the slumber mode M13 after the standby immediate command execution completion report (command completion response), the speed of the completion response to the subsequent check power mode command decreases. End up. For this reason, in this embodiment, the SATA bus 30 is not immediately and unconditionally shifted to the slumber mode M13 after the command completion response.

  This will be described in more detail. First, assume that the host 20 issues a check power mode command to the HDD 10 immediately after the transition to the slumber mode M13 at the end of the standby immediate command. In this case, when the check power mode command is issued, the SATA bus 30 has already shifted to the slumber mode M13. In order to transmit a command from the host 20 to the HDC 119 of the HDD 10 through the SATA bus 30 in this state, the SATA bus 30 must be able to communicate, that is, return to the idle mode M11. At this time, the SATA interface control circuit 22 in the host 20 executes the return procedure according to the state transition rule of the SATA interface according to the check power mode command. In this case, the host 20 recognizes that the check power mode command completion response is delayed by the return time of the SATA bus 30.

  The command (check power mode command) issued from the host 20 returns the state of the SATA bus 30 from the slumber mode M13 (power save state) to the idle mode M11 in response to the issue of the command. After reaching the HDD 10, the HDD 10 is reached. Then, the link / transport layer processing unit 122 (transport layer processing unit included therein) of the SATA interface control circuit 12 operates to issue a command to the HDC 119 in the HDD 10. For this reason, the command issued from the host 20 reaches the HDC 119 in the HDD 10 with a delay corresponding to the return time of the SATA bus 30. However, the HDC 119 cannot recognize the delay.

  Therefore, in the present embodiment, when trying to control the SATA power save mode, the CPU 130 in the HDD 10 first receives a certain number of commands indicated by the command reception time information stored in the command reception time storage area 120b of the buffer RAM 120, for example. The command reception frequency is calculated from the time series (step S7). Here, as the command reception frequency, for example, an average value of command reception time intervals indicated by a command reception time series or a command reception time interval having the highest probability can be used. It should be noted that a series of command reception times received within a certain period of time based on the current time may be used instead of a certain number of command reception time series.

  The CPU 130 determines the transition timing to the SATA power save mode determined by the command received this time from the calculated command reception frequency (command reception time interval), waits for the arrival of the timing, and then the SATA power save mode. The transition to is controlled (step S8). Here, assuming that the calculated command reception frequency, that is, the command reception time interval is Tc, the CPU 130 waits for the time Tc and the next command is not received by the HDC 119. The SATA interface control circuit 12 makes a transition to the SATA power save mode determined by (step S9). Thus, even when the transition to the SATA power save mode determined by the command is controlled at the time of executing the ATA power save command, when the next command is sent from the host 20, the completion response to the next command is sent. Can be delayed.

  In consideration of the high possibility that the host 20 issues a check power mode command to the HDD 10 after the ATA power save command, the CPU 130 stops the SPM 113 after the ATA power save command completion response. Even when the transition to the slumber mode M13 is controlled after a predetermined time from the confirmation time point, it is possible to prevent the completion response to the next command from being delayed. In addition, the transition to the slumber mode M13 may be controlled after a certain time from the most recent reception of a command that does not require the SPM 113 to be restarted. In the present embodiment, the SATA power save mode is set to the slumber mode M13 when the ATA power save command from the host 20 is an idle command, a standby command command, or a sleep command. However, depending on the type of command or the configuration of the SATA interface control circuit 12 (capability of returning to the idle mode M11), the transition may be made to the partial mode M12 that can be recovered in a shorter time.

  In the present embodiment, in order to reduce the power consumption in the HDD 10, as shown in FIG. 3, the ATA power save mode transitions autonomously inside the HDD 10, separately from the ATA power save command from the host 20. The configuration to be performed is applied. That is, the CPU 130 in the HDD 10 immediately transitions from the read / write mode M0 to the active / idle mode M1 when the read / write execution in the read / write mode M0 ends. Further, after the transition to the active / idle mode M1, if no new command is sent from the host 20 even after the predetermined time T1 has elapsed, the CPU 130 in the HDD 10 changes from the active / idle mode M1 to the performance / idle mode M2. Transition to. If no new command is sent from the host 20 after the transition to the performance / idle mode M2, the CPU 130 transitions from the performance / idle mode M2 to the low power / idle mode M3. Let Here, the times T1 and T2 may be dynamically changed from the command reception frequency (command reception time interval) described above, for example, periodically.

  In this embodiment, at the time of transition of the autonomous ATA power save mode under the control of the CPU 130 inside the HDD 10, as shown in FIG. 3, the SATA power save mode is also shifted in conjunction with the transition. Specifically, at the time of transition from the read / write mode M0 to the active / idle mode M1, the transition is made from the idle mode M11 to the partial mode M12. When the transition from the active / idle mode M1 to the performance / idle mode M2 is made, the partial mode M12 is continued. Further, when the performance / idle mode M2 transitions to the low power / idle mode M3, the transition is made from the partial mode M12 to the slumber mode M13. In the low power / idle mode M 3, the head 112 is moved to a retreat location that is out of the disk 111. When the HDD 10 is in this state, the time required to return to the read / write mode M0 when a read / write command is subsequently given from the host 20 is as long as 30 ms or longer (see FIG. 6). Therefore, in such a case, it is effective to set the SATA bus 30 to the slumber mode M13 and suppress the power consumption in the SATA bus 30 (SATA interface) as in this embodiment.

  Access from the host 20 to the HDD 10 tends to be concentrated or distributed in time series. For example, after a command reception time interval continues for a very short time, a command may not be received for a certain time. In such a case, it is preferable that the CPU 130 assumes that the execution of the application in the host 20 has been completed and sets the ATA power save mode in which the power consumption is reduced in a relatively short time. Further, although the command reception time interval is relatively long, if the state continues for a long time, that is, when the HDD 10 is continuously accessed, the time until the CPU 130 reduces the power consumption is relatively long. Set to power save mode. Again, the SATA power save mode may be controlled in conjunction with these SATA power save modes.

  In the present embodiment, the SATA power save mode (power save of the SATA bus 30) is controlled by the CPU 130 in the HDD 10. However, a configuration in which this control is performed by the SATA interface control circuit 12 is also possible. FIG. 8 shows a state transition when the SATA power save mode is controlled by the SATA interface control circuit 12. It is assumed that the SATA bus 30 has transitioned (returned) to the idle mode M11 as a result of receiving a command from the host 20 by the SATA interface control circuit 12. If a new command is not sent from the host 20 even after a predetermined time T has elapsed since the transition to the idle mode M11, the SATA interface control circuit 12 transitions the SATA bus 30 from the idle mode M11 to the partial mode M12. To control. If a new command is not sent from the host 20 even after a predetermined time T has elapsed since the transition to the partial mode M12, the SATA interface control circuit 12 changes the SATA bus 30 from the partial mode M12 to the slumber mode M13. Control to transition. This slumber mode M13 is continued until a new command is sent from the host 20. Here, the fixed time T may be measured using a timer (time measuring means). Note that when the transition is made from the idle mode M11 to the partial mode M12, the partial mode M12 may be continued until a new command is sent from the host 20. It is also possible to adopt a configuration in which the transition is made directly from the idle mode M11 to the slumber mode M13. Further, the HDA 119 in the HDD 10 can be provided with a SATA power save mode control function by the SATA interface control circuit 12.

  In the present embodiment, control of the SATA power save mode (power save of the SATA bus 30) is performed from the HDD 10 side (that is, under the initiative of the HDD 10). In order to control the SATA power save mode, not only the SATA interface control circuit 12 on the HDD 10 side but also the SATA interface control circuit 22 on the host 20 side are compatible with the SATA power save mode (that is, the SATA power save mode). Support the function). If the SATA interface control circuit 22 does not support the SATA power save mode (the partial mode M12 and the slumber mode M13), the transition to the instructed SATA power save mode is impossible. Regarding this state, a method that can be known by the mutual operation of the SATA interface control circuits (SATA interface control circuits 12 and 22 in this embodiment) interconnected by the SATA bus is defined in the SATA interface standard. It is assumed that the host 20 to which the HDD 10 is connected via the SATA bus 30 does not support the slumber mode M13 (including the SATA interface control circuit 22). In this case, whenever an instruction to shift to the slumber mode M13 from the HDD 10 side (a primitive including a pattern representing the same) is issued to the host 20, the host 20 (internal SATA interface control circuit 22) enters the slumber mode M13. A non-transitionable response is returned. As described above, when the host 20 to which the HDD 10 is connected via the SATA bus 30 does not support the SATA power save mode, the HDD 10 issues an instruction to shift to the SATA power save mode to the host 20. However, the host 20 always returns a non-transferable response, and the SATA power save mode control fails. That is, when the HDD 10 is connected to the host 20 that does not support the SATA power save mode via the SATA bus 30, it is useless for the HDD 10 to perform the control of the SATA power save mode.

  Therefore, in the present embodiment, when the response indicating that the host 20 cannot make the transition to the SATA power save mode is returned, that is, when the control of the SATA power save mode fails, the CPU 130 in the HDD 10 stores the response in the buffer RAM 120. The SATA power save disable flag F stored in the flag storage area 120a is turned on (steps S9 and S10). As a result, when it becomes necessary to control the SATA power save mode next time, the CPU 130 can determine whether the SATA power save is impossible by referring to the state of the SATA power save disable flag F. (Steps S5 and S6). When the SATA power save disable flag F is in the ON state, the CPU 130 determines that SATA power save is not possible. In this case, the CPU 130 refrains from executing the control in the SATA power save mode (steps S7 and S8). As a result, although the SATA interface control circuit 22 of the host 20 does not support the SATA power save mode, it is possible to prevent the control for unnecessary state transition in the SATA power save mode from being performed. The operation of the bus 30 can be stabilized.

  When both the HDD 10 and the host 20 are compatible with the SATA power save mode, the SATA power save mode can be controlled from the host 20 side (that is, under the initiative of the host 20). However, in the HDD 10, state transition to the ATA power save mode is autonomously performed separately from the ATA power save command from the host 20. Therefore, rather than controlling the SATA power save mode of the SATA bus 30 from the host 20 side regardless of the ATA power save mode in the HDD 10, the HDD 10 side is linked to the ATA power save mode in the HDD 10 as in the above embodiment. Therefore, the SATA power save mode suitable for the ATA power save mode in the HDD 10 can be set by controlling the SATA power save mode of the SATA bus 30.

  In the above embodiment, the case where the present invention is applied to a system including an HDD (magnetic disk drive) has been described. However, the present invention is not limited to a system having a disk drive other than an HDD such as an optical disk drive or a magneto-optical disk drive, or even a system having an electronic device other than a disk drive, as long as the system has an electronic device having a SATA interface. Applicable.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

  DESCRIPTION OF SYMBOLS 10 ... HDD (magnetic disk drive, electronic device), 11 ... HDD main body, 12, 22 ... SATA interface control circuit (serial ATA interface control circuit), 13, 23 ... ATA bus, 20 ... Host, 21 ... Host main body, 30 ... SATA bus (serial ATA bus), 111 ... disk, 112 ... head, 113 ... SPM (spindle motor), 116 ... motor driver, 117 ... head IC, 118 ... read / write IC, 119 ... HDC (disk controller), 119a: Status register, 120: Buffer RAM, 120a: Flag storage area, 120b: Command reception time storage area, 130: CPU

Claims (11)

In an electronic device having a serial ATA interface connected to a host via a serial ATA bus,
Receiving an instruction to set the electronic device output from the host to the first power save mode, and executing the received command to set the electronic device to the first power save mode; Reporting means for reporting completion of execution of the received command to the host;
After the execution completion report of the received command, the serial ATA interface associated with the first power save mode based on the correspondence between the first power save mode and the second power save mode of the serial ATA interface An electronic device having a serial ATA interface, comprising: control means for controlling the setting of the second power save mode. The command specifying the first power save mode is a sleep command, a standby command or an idle command defined by the ATA interface standard,
The second power save mode is a slumber mode or a partial mode
The electronic apparatus having a serial ATA interface according to claim 1. Means for detecting whether the host side supports a power saving function of a serial ATA interface based on the control by the control means;
Means for storing flag information indicating the detection result;
The control means refers to the flag information before the control, and refrains from the control when it is detected from the flag information that the host side does not support the power saving function of the serial ATA interface. The electronic device having a serial ATA interface according to claim 1. Measuring means for starting time measurement for measuring a predetermined time each time the serial ATA interface shifts to the idle mode or the partial mode which is one of the power save modes;
The serial ATA interface is shifted from the idle mode or the partial mode to the partial mode or the slumber mode when the command from the host is not received when the predetermined time is measured by the measuring unit. With transition means to
The electronic apparatus having a serial ATA interface according to claim 1, further comprising: The electronic device includes a disk drive.
An electronic apparatus having a serial ATA interface according to any one of claims 1 to 4. In a controller provided in an electronic device having a serial ATA interface connected to a host via a serial ATA bus,
Receiving an instruction to set the electronic device output from the host to the first power save mode, and executing the received command to set the electronic device to the first power save mode; Reporting means for reporting completion of execution of the received command to the host;
After the execution completion report of the received command, the serial ATA interface associated with the first power save mode based on the correspondence between the first power save mode and the second power save mode of the serial ATA interface And a control means for controlling the setting of the second power save mode. The command specifying the first power save mode is a sleep command, a standby command or an idle command defined by the ATA interface standard,
The second power save mode is a slumber mode or a partial mode
The controller according to claim 6. At least one of the electronic devices according to claim 1;
A host using the electronic device;
A serial ATA bus to which the electronic device and the host are connected;
An information device comprising: The command specifying the first power save mode is a sleep command, a standby command or an idle command defined by the ATA interface standard,
The second power save mode is a slumber mode or a partial mode
The information device according to claim 8. A power saving method of a serial ATA bus in an electronic device having a serial ATA interface connected to a host via a serial ATA bus,
Receiving an instruction to set the electronic device output from the host to the first power save mode, and executing the received command to set the electronic device to the first power save mode; Reporting completion of execution of the received command to the host;
After the execution completion report of the received command, the serial ATA interface associated with the first power save mode based on the correspondence between the first power save mode and the second power save mode of the serial ATA interface And setting a second power saving mode of the serial ATA bus. The command specifying the first power save mode is a sleep command, a standby command or an idle command defined by the ATA interface standard,
The second power save mode is a slumber mode or a partial mode
The power saving method for a serial ATA bus according to claim 10.

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