JP2533949B2 - Spindle synchronization pulse control method for magnetic disk unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] In a device in which a plurality of magnetic disk devices are mutually connected by a two-wire bus and a spindle synchronization signal transmitted from a device set as a transmitting side is set as another receiving side. Regarding a magnetic disk device in which the rotation of each motor is received and controlled, even if a plurality of devices in a magnetic disk subsystem including a plurality of magnetic disk devices are set in a master mode, circuit elements in other slave modes The purpose of the present invention is to provide a spindle synchronization pulse control method in a magnetic disk device that can prevent the destruction of the magnetic disk device. The transmission circuit of the magnetic disk device that is set as a master has the characteristic of being in a high impedance state when the output is open. , Open the signal input terminal and input the sync pulse signal to the enable terminal to reverse two positive phases The receiving circuit of the magnetic disk device which outputs the output of each phase to the two-wire bus and which is set as a slave connects the signal on the positive phase side of the two-wire bus to the negative-phase input terminal and the negative-phase side. The signal of is input to the positive phase input terminal and received.

The present invention relates to a device in which a plurality of magnetic disk devices are mutually connected by a two-wire bus and a spindle synchronization signal transmitted from a device set as a transmission side is set as another reception side. The present invention relates to a spindle synchronization pulse control method in a magnetic disk device that receives and controls the rotation of each motor.

In recent years, in the field of magnetic disk subsystems, a magnetic disk device is required to have a spindle synchronization function in order to realize high-speed data processing. This spindle synchronization synchronizes the rotation of the motor that drives the rotation of the disks of each magnetic disk device, so that no matter which of the plurality of magnetic disk devices is accessed from the control device, the same transfer is performed as the same magnetic disk device. This is so that processing can be performed.

If such a function is not provided, the motor will rotate in a slightly different phase for each magnetic disk device, and a waiting time for rotation will occur in the host device using this, and the efficiency of data transfer will deteriorate.

[Prior Art] FIG. 3 is a block diagram of a conventional magnetic disk subsystem, FIG. 4 is a conventional spindle synchronization signal control system, and FIG. 5 is a timing diagram of a conventional spindle synchronization signal.

In FIG. 3, 30 is a controller (CNTL) of a magnetic disk subsystem consisting of a plurality of magnetic disk devices, 3
1 is a magnetic disk device set as a master, 32 is a magnetic disk device set as a plurality of slaves, 33 is an interface cable (I / F cable) for transferring data and control signals, 34 is spindle synchronization (spindle) -Also called a sink: "Synchro" is an abbreviation of Synchro) represents a spindle-sync cable for transferring signals.

The controller 30 has an interface with a higher-level device and controls the magnetic disk subsystem and data transfer. In the example shown in the figure, spindle synchronization is in slave mode. In this magnetic disk subsystem, the magnetic disk device 31 is the master of the spindle synchronization signal in the case of the figure, but the master / slave setting means (for example, by a dip switch and command) is installed inside the magnetic disk device. It is provided, and it does not matter which magnetic disk unit becomes the master. Further, all the magnetic disk devices can be in the slave mode and the controller 30 can be in the master mode.

FIG. 4 shows the control method of the spindle synchronization signal. Fourth
42 and 43 in the figure are bus lines which form a two-wire bus corresponding to the spindle / sink cable 34 in FIG. 3 and perform balanced transmission, 40
Is a magnetic disk device set in the master mode (hereinafter referred to as a master device) among the magnetic disk devices that perform spindle synchronization control, and 41 represents a magnetic disk device that performs spindle synchronization control set in a plurality of slave modes ( Hereinafter referred to as a slave device). Note that other interface lines and circuits related thereto are omitted in this figure.

The operation of FIG. 4 will be described with reference to FIG. 5. In the master device 40, as shown in FIG. 5 from the sync pulse signal generating circuit unit 401 to the signal input terminal of the differential amplification type transmission circuit 402. A synchronous signal is output. At this time, the transmitter circuit 40
The * master (* MASTER, where * is an inverted sign) signal is supplied to the enable terminal of 2 to enable the spindle synchronization signal to be transmitted as a master.

In this case, one output terminal of the transmission circuit 402 is connected to the line 42
The spindle sync signal (sync pulse signal) positive phase (SY
The output having the waveform shown in FIG. 5 is generated, and the output having the waveform shown in FIG. 5 is generated from the other output terminal to the bus line 43. That is, when the sync pulse signal appears, the bus line 42 becomes almost high level and the other sections become low level, the bus line 43 becomes low level when the spindle synchronizing pulse appears, and the other sections become high level. There is.

Such a sync pulse signal is received by the receiving circuit 410 of another slave device 41. In this case, the signals of the two lines 42 and 43 are input to the positive phase input terminal and the negative phase input terminal of the differential amplification type reception circuit 410 similar to the transmission circuit. The output of this receiving circuit is as shown in FIG.
The waveform is the same as the output of the synchronizing pulse signal generating circuit unit 401. In FIG. 4, for convenience of explanation, the master device 40 is provided with a sync pulse signal generation circuit unit 401 and a transmission circuit 402, and the slave device 41 is provided with a reception circuit 410 and a motor control circuit unit 41.
1 is shown as being provided, but in practice the master device 40 is also provided with a receiver circuit and a slave device.
41 is also provided with a synchronizing pulse signal generating circuit section and a transmitting circuit, has the same configuration, and can be switched to a master or a slave by setting means.

[Problems to be Solved by the Invention] According to the above-described conventional spindle synchronization signal control method, there is no problem when only one device is set to the master mode from a plurality of magnetic disk devices and controllers. However, if a plurality of devices are mistakenly set to the master mode, synchronization pulse signals will be generated from the devices in the plurality of master modes.

Then, the bus line (shown in FIG.
42,43) causes a bass fight. That is, sync pulse signals generated from a plurality of master devices are generated as shown by the dotted line in FIG. 5, and when one master device generates the level of the sync pulse signal, the other master device outputs the same line. The signal of the opposite level is generated. Then, the level of the two-wire type bus line becomes abnormal, the elements of the receiving circuit of the other slave mode device may be destroyed, and the sync pulse signal cannot be recognized normally. Therefore, in the conventional method, it is difficult to detect that a plurality of such devices are set in the master mode, and the detection circuit is not provided.

The present invention can prevent the destruction of circuit elements in other slave modes even if a plurality of devices in a magnetic disk subsystem having a plurality of magnetic disk devices are set in a master mode. An object is to provide a pulse control method.

[Means for Solving the Problems] FIG. 1 is a basic configuration diagram of the present invention.

The connection configuration is shown in A. and the signal timing is shown in B. in FIG.

In the figure, 10 is a master mode magnetic disk unit, 11
Is a transmission circuit that becomes a high impedance state when the output is open, 110 is a signal input terminal, 111 is an enable terminal, 112 is a positive phase output terminal, 113 is a negative phase output terminal, 12 is a sync pulse generation circuit,
Reference numerals 13 and 14 are 2-wire type buses, 15 is a slave mode magnetic disk device, 16 is a receiving circuit, 160 is a positive phase input terminal, 161 is a negative phase input terminal, and 17 is a motor control circuit.

The present invention uses a circuit that becomes high impedance when the output is opened in the transmission circuit of the master mode device, generates a signal output only when the pulse of the spindle synchronization signal is output to the 2-wire bus, and sets it to the high impedance state in the other sections, and The mode receiving circuit receives the spindle synchronizing signal.

[Operation] The transmission circuit 11 of the master mode magnetic disk device 10 is a known transmission circuit (driver) having a characteristic that when the output is opened, the output is in a high impedance state. The signal input terminal 110 of the transmission circuit 11 is used in a logical H level state. At this time, since the power supply voltage is supplied to the signal input terminal through the pull-up resistor, the signal input terminal becomes high level (close to logic "1"). At the same time, a signal obtained by inverting the output of the sync pulse generation circuit 12 is supplied to the output drive enable terminal 111 of the transmission circuit 11. The positive-phase output terminal 112 and the negative-phase output terminal 113 of the transmission circuit 11 are output to the two bus lines 13 and 14 of the two-wire bus.

Then, the sync signal pulse (SYCP
(Displayed by L), an output such as on the bus line 13 and an output on the bus line 12 occur. In this waveform, bus lines 13 and 14 are used in sections other than pulse signal sections.
Is in a high impedance state, and the signal levels of the two bus lines are the same level, which is lower than the normal high level (logic “1”).

A plurality of magnetic disk devices 15 in the slave mode are provided with a receiving circuit (receiver) 16 having the same configuration as the transmitting circuit 11, and one bus wire 13 of the two-wire bus is connected to the negative phase input terminal 161, Line 14 connects to the positive phase input terminal 160. In the receiving circuit 16, the waveform signal of FIG.
When it appears in 4, the output is high level in the high impedance state, but the low level signal is generated only during the period when the sync pulse signal appears.

An output obtained by inverting the output of the receiving circuit 16 has a waveform shown in FIG. 1B, which is input to the slave mode motor control circuit 17 to control the rotation of the drive motor of the magnetic disk device.

With such a synchronous pulse control method, even if a plurality of magnetic disk devices are set to the master mode,
Since the signal level is detected on the 2-wire bus only when the sync pulse signal appears, an abnormal level is not input to the receiving circuit of the other slave mode device, so that the circuit element is not destroyed and is kept constant. It is possible to easily detect that a plurality of sync pulse signals are generated within a cycle.

[Embodiment] FIG. 2 (a) is a configuration diagram of the embodiment, and FIG. 2 (b) is an example of operation waveforms.

In FIG. 2A, 20 is a magnetic disk device, 21 is an interface driver / receiver connected to an interface (IF) bus including data lines and control signal lines, 22 is a command decoder circuit for decoding commands from the controller, 23 is a spindle sync pulse signal for sync pulse 2
Receiver / driver that transmits / receives via wire bus, 24 is an oscillator using crystal, 25 is a spindle synchronization pulse generation circuit, 26 is a motor synchronization that generates a control signal to synchronize with the spindle synchronization pulse input to the motor A control circuit unit, 27 is a motor drive control circuit unit that drives and controls the motor under the control of the motor synchronization control circuit unit, and 28 is a DC motor that drives the rotation of the disk.

Driver (DV) 23 provided in the receiver / driver 23
The 2 and the receiver 231 (RV) are conventionally known circuits, and are tri-state circuits that enter a high impedance state when the input terminals are opened. For example, DS36
There is 95 (National Semiconductor).

When a mode setting command is input from the controller (or higher-level device) to this magnetic disk device 20 via the interface bus, it is decoded by the command decoder circuit 22 through the IF driver / receiver 21, and depending on the content of the command. Slave mode or * master mode setting output is generated.

* If a master mode setting output occurs, the driver
232 and the spindle synchronization pulse generation circuit unit 25 are activated to start the operation. In this case, the spindle sync pulse generation circuit section 25 outputs a sync pulse signal generated at a predetermined cycle using the oscillation output of the oscillator 24. On the other hand, this spindle sync pulse signal is used by the motor sync control circuit of the device itself.
It is supplied to 26 and used for synchronous control of the motor of this magnetic disk device, and on the other hand, it is input to the positive phase input terminal of the driver 232. At this time, the negative-phase input terminal of the driver 232 is opened, but 5V power is applied via the pull-up resistor. The positive and negative phase outputs of the driver 232 are output to the two-wire buses (SYCPLL and SYCPLH), respectively. At this time, since the receiver 231 has not been activated, the receiving operation is not performed.

Next, the case where the slave mode setting output occurs will be described. The receiver 231 starts up and starts operating. At this time, the driver 232 is not started and does not operate. In this case, input one of the two wires (SYCPLL) to the positive phase input terminal and the other (SYCPLH) to the negative phase input terminal. This receiver
The 231 receives an input from this bus, generates a high level output when in a high impedance state, and outputs a low level signal as an output when a spindle synchronization pulse appears.

FIG. 2B shows the timing when a plurality of master devices are set.

That is, when a plurality of magnetic disk devices having the configuration shown in FIG. 2 (a) are connected to each other by a 2-wire bus, # 1
When # 2 and # 2 are set to the master mode, sync pulse signals as shown by and in FIG. 2B are generated from the respective devices in the master mode. On the other hand, in the case of the slave device of the conventional example (FIGS. 3 to 4), a bus fight occurs for each synchronization pulse signal, and an abnormal level occurs, and duplication of the master mode device cannot be detected. It was However, in the slave device according to the present invention, as shown in, the period other than the sync pulse signal is always in the open state (high impedance state), so that a plurality of sync pulses are individually detected in the wired or OR format. can do. Therefore, when multiple spindle synchronization pulses are detected within a certain period, it is known that an abnormality has occurred, and investigations and tests are performed accordingly, and the cause (multiple devices are set to master mode) is determined. Can be identified.

[Advantages of the Invention] According to the present invention, it is possible to detect an abnormality in the spindle synchronization pulse and provide the magnetic disk subsystem with a highly reliable spindle synchronization function.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 (a) is a configuration diagram of an embodiment of the present invention, and FIG. 2 (b) is an example of operation waveforms of the embodiment,
FIG. 3 is a block diagram of a conventional magnetic disk subsystem, FIG. 4 is a conventional spindle synchronization signal control system, and FIG. 5 is a conventional spindle synchronization signal timing. In Fig. 1, 10: magnetic disk unit in master mode 11: transmission circuit 110: signal input terminal 111: enable terminal 112: positive phase output terminal 113: negative phase output terminal 12: sync pulse generation circuit 13, 14: 2 wires Bus 15: Magnetic disk unit in slave mode 16: Receiver circuit 17: Motor control circuit

Claims (1)

(57) [Claims] 1. A plurality of magnetic disk devices are mutually connected by a two-wire bus through a transmission circuit and a reception circuit,
In the magnetic disk device in which the rotation of each motor is controlled by receiving the spindle synchronization signal transmitted from the magnetic disk device set as one of the masters in the magnetic disk device set as the other slave, The transmission circuit (11) of the magnetic disk device (10) set as is provided with a characteristic of being in a high impedance state by setting the enable terminal to a disable state,
The signal input terminal (110) is fixed to a predetermined state, and the synchronous pulse signal is input to the enable terminal (111) to output two positive and negative phase outputs to the 2-wire bus (13, 14), respectively. Then, the receiving circuit (16) of the magnetic disk device (15) set as a slave connects the signal on the positive phase side of the two-wire bus to the negative phase terminal and sends the signal on the negative phase side to the positive phase terminal. A spindle synchronization pulse control method in a magnetic disk device characterized by input and reception.