JPS62202355A - Magnetic disk control device - Google Patents

Abstract

PURPOSE:To detect easily and surely missing of a ready signal without applying a load on the firmware in the titled device by providing a circuit judging the presence of the missing of the ready signal from the state of change in the ready signal and a ready signal missing detection circuit comprising storing the information being the result of judging. CONSTITUTION:The ready signal missing detection 15, if a drive select signal changes from the selecting state into the non-selecting state due to any cause, confirms the state to be consecutive for a prescribed time, holds a ready signal returned from corresponding magnetic disk devices 2<1>, 2<2> attended with the issue of an alternate drive select signal generated in the inside in place of the drive select signal, judges the presence of generation of the loss of the ready signal from the state transition of the ready signal to hold the information being the result of judgment. The information being the result of judgment held by the ready signal missing detection circuit 15 is read by a microprocessor 11 in a controller 1 to detect the loss of ready signal surely and easily.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a magnetic disk control device having an interface mechanism for specifying a magnetic disk device using a drive select signal and transmitting a control signal to the device. In the
In particular, the present invention relates to a magnetic disk control device having a function of preventing the occurrence of an abnormality caused by a ready signal drop.

(Prior art) Magnetic disk device with 8T506 interface (
The drive (hereinafter referred to as drive) is connected to a control device as shown in FIG. In Fig. 4, 01 is the control device, 02.0
2... is a drive cable, 03 is a data cable, and 04 is a control status cable. Further, 011 to 014 are internal components of the control device 01, and 0
11 is a microprocessor (μmp), 012 is a host interface section, OXS is a hard disk control section (H2C section), and 014 is a drive interface section. Here, control device 01 and drive 02
The signal cable between the
It is used to send and receive each signal via the interface, and is connected to the control status cable 04 and data cable θ.
Consists of 3.

The control status cable 04 is connected to the disabling chain and is used for sending and receiving control commands and status information. These signals are the drive select signal (Driv@S@1ect 1 in Figure 5).
p Drive@5elect 2 r Dr.va 5
Only the drive (72i) selected by select 3 eDriv@5elsct 4 ) can receive and accept control signals and also send output status to control unit fO.

The data cable 03 is radially connected and includes a write data differential signal line, a read data differential signal line, and a signal line for responding to a drive select signal.

By the way, in a drive with a 5T506 interface, normally when the power is turned on, it automatically executes Caliplade and returns to track 0, and if there is no abnormality, the ready signal (Rsady) of the control status cable 04 is output.
) is output. On the other hand, head position information, that is, information indicating which track the head is currently located on is managed by the control device θ. Therefore, for example, if the power supply for control device 01 and the power supply for drive 02 are separate, there may be cases where the power on the drive 02 side is accidentally turned off and then on again, or an abnormality such as a momentary power outage occurs in the power supply on the drive 02 side. In this case, the ready signal (R・ady) drops and the head in track N automatically returns to track O using the caliper plate, and if there is no other abnormality, the f4 signal (R
@ady) is re-output. During this time, control device O1 can detect this ready signal drop if it is outputting the drive select signal, but if it is not outputting the drive select signal or is unable to output it, it will miss this ready signal drop. . Furthermore, although the control device θ1 assumes that the head of P-Ripe 02 is on track N, it is actually on track O, and if a command is subsequently executed, will this cause an error? Or, it may progress to data destruction.

(Problems to be Solved by the Invention) As described above, in the conventional method, it is not possible to reliably detect the occurrence of a ready signal drop, which results in the occurrence of failures due to the ready signal drop, resulting in poor reliability. There was a problem.

The present invention provides a magnetic disk control device having an interface mechanism for specifying a magnetic disk device using a drive select signal and transmitting a control signal to the device.
Magnetic disk control that can reliably and easily detect a ready signal drop without putting a burden on the processing mechanism within the device, thereby preventing damage caused by a ready signal drop and ensuring highly reliable operation. Provide equipment.

[Structure of the invention]

(Means for Solving the Problems) The present invention detects that the drive select signal changes to a non-selected state and remains in the non-selected state for a certain period of time, and upon this detection, the drive select signal is A circuit that prohibits the issuance of the signal and issues an internally generated alternative drive select signal, and a circuit that holds the ready signal returned from the corresponding magnetic disk device upon issuing the alternative drive select signal, and detects the ready signal from the change in the state. A ready signal drop detection circuit is provided, which includes a circuit for determining whether a drop occurs or not, and a circuit for holding information on the determination result.

(Function) When the drive select signal changes from the selected state to the non-selected state for some reason, the ready signal drop detection circuit confirms that this state continues for a certain period of time and detects the corresponding magnetic disk drive. On the other hand, instead of the drive select signal described above, an alternative drive select signal generated internally is sent out. It then holds the ready signal returned from the corresponding magnetic disk device upon issuing this alternative drive select signal, determines whether a ready signal drop has occurred based on the state transition of the ready signal, and holds information on the determination result. do. The micro:f processor in the control device reads the information of the judgment result held in the ready signal drop detection circuit at an appropriate timing and recognizes whether or not a ready signal drop has occurred. Thereby, it is possible to reliably and easily detect a ready signal drop without placing a burden on the firmware in the control device, and it is possible to prevent the above-mentioned various failures from occurring due to the occurrence of a ready signal drop.

(Example) An example of the present invention will be described below with reference to the drawings. still,
In order to simplify the explanation, an example is shown here in which two magnetic disk devices are connected as control targets to a magnetic disk control device.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1 is a magnetic disk control device (hereinafter simply referred to as a control device) according to the present invention, and 21 is a magnetic disk control device (hereinafter simply referred to as a control device).

Reference numeral 22 denotes a magnetic disk device (hereinafter referred to as a drive) which is controlled by the control device 10. Signal cables 3 and 4 connect the control device 1 and the drive 21g2M, of which 3 is a data cable and 4 is a control status cable. Reference numerals 11 to 15 each constitute an internal component of the control device I, where 1 is a microprocessor (μmp), 12 is a host interface unit, 13 is a HDC (hard disk control) unit, and 14 is a drive interface unit. It is.

Reference numeral 15 denotes a ready signal drop detection circuit (hereinafter referred to as "ready drop detection circuit") newly provided in the present invention, which detects and holds whether a ready signal drop occurs when the drive select signal is interrupted. , its detailed circuit configuration is shown in FIG.

FIG. 2 is a circuit block diagram showing the internal circuit configuration of the ready failure detection circuit 15. As shown in FIG. In the figure, numeral 5 indicates a control circuit (hereinafter referred to as CNT) that controls the inside of the readiness detection circuit 15. 52 and 53 are drive select signals (DUEL 1 ,
osgt, 2) as the dirt signal G from CNT 51
output control according to A, usually CN
The f-) signal (GA=''H1gh'') from T51 opens the drive select signal (DSE).
L 1 , DSEL 2 ) are passed through as is, but this drive select signal (DSIL 1 jDSE
When L 2 ) is interrupted, r from the above CNT 51
- After the time T1 shown in FIG. 3 has elapsed, the signal GA goes low at time T3, and the dart is closed during that period.

54 and 55 are the drive select signals that have passed through the AND darts 52 and 53, and the dart signal GB1.5 from the CNT 5J. In response to GB's wishes, Drive 21.

Drive select signal (Drive 5elec) to 22
t 1 *Drlv・S・1sct 2 ).

56 and 57 are ready signals from Drive '1+2 Snow (
Ready ) as dirt signal G J from CNT 51
This is an AND gate whose output is controlled by +GB*.

58 and 59 are the D type flip-flops (hereinafter referred to as D type F/F) that hold the ready signal output from 56 and 57, and 60 and 6 are the second stage D flip-flops (hereinafter referred to as D type F/F).
It is the D type φ of the second stage.

The D-ties 7°F/F 58, 59 and 60°61 in each stage hold input data and output held data in accordance with the strobe signal (sp) output from the CNT 5J, respectively.

62 and 63 are the first stage D tie-IF/F58°59
Reset output (mutual) and second stage D type F/F'
It is an AND gate that receives the set outputs (Q) of 60 and 61 and outputs a ready-fall detection signal when the ready signal held last time is ``H1gh'' and the ready signal held this time is ``Lov''. .

64 and 65 are Ss that hold the ready drop detection signal (@H1gh') output from the AND gaters 2 and 63.
This is an R-type flip-flop II lower 8R tie 7' (referred to as F/F). This SR type F7F'64.65 is a reset signal (R) output from CNT 51 after the ready detection signal is read by the microprocessor IJK.
It is reset by .

66 and 67 are output buffers that control the output of the ready fall detection signal held in the SR type FA'' 64 and 65 by the output enable signal (OE) output from the CNT 51 in accordance with the read signal (RCMD) from the microprocessor 11. I'll go.

Figures 3 (&) to (k) respectively show the signal states of each part of the circuit shown in Figure 2 above, and here each signal is shown with "Hlgh'("1#)" as "true". There is.

The operation of one embodiment will now be described with reference to FIGS. 1 to 3.

First, when the drive select signal (DSEL 1 or psr:L2) from the dry interface unit 14 is interrupted and becomes "Lovr", the CNT 51 of the ready drop detection circuit 15 detects this ready signal drop. T! Detect time-time. And C
In order to prohibit the drive select signal, the NT 5 J sets the e-) signal GA to "LoV" and instead sets the date signal CB or CB to "Hl gh".

These dirt signals QB and GB are shown in Fig. 3 (c), (・)
As shown in the figure, take turns at the timing of "Hl"
gh” and the drive select signal (DriMa・S@
Drive 2+ (1=1 or
2) Select.

If the selected dry fz is in the f state, the ready signal 4 at the “Hl gh” level is output.
) is sent to the control device l. On the other hand, L in the control device 1
; The CNT 51 provided in the drop detection circuit 15 is connected to the drive 2. It waits for the ready signal (Ready) from to become stable, and generates the strome signal sp after 73 hours as shown in FIG. 3(h). This causes drive 2. The ready signal (R・ady) sent from the first stage p-tie 7'F/? 5 B or 59 and the first stage D tie fF/F s s
.

The content of 59 is the second stage D tie 7'F/F'
150.61.

Here, for example, if the ready signal (R@ady) sent from the drive 21 is rarely at "LoW" as shown by the broken line in FIG. 3(g), the SR tie 7 "F/)'
64 or 65 is in sect state, Ready -4R
The ready state, that is, the occurrence of a ready signal drop can be notified to the outside.

The microprocessor 11 outputs a read signal (RCMD)
is sent to the ready-fall detection circuit 15, and this SR tie f
F/Fe4. From the output buffer 6.67 that holds the output of as, its held data (Dl.

By reading D2), the occurrence of this abnormal state can be detected at an appropriate time (for example, at the time of status check before command output).

As described above, by detecting the occurrence of a ready signal drop using the ready drop detection circuit 15, the drive 21.
2. It is possible to reliably check the status of the microprocessor 11, thereby improving the processing capacity and processing speed of the microprocessor 11, and simplifying processing including firmware.

〔Effect of the invention〕

As detailed above, according to the magnetic disk control device of the present invention, it is detected within the device that the drive select signal has changed to the non-selected state and remains in the non-selected state for a certain period of time,
When this is detected, a circuit that prohibits the issuance of the drive select signal and issues an internally generated alternative drive select signal, and a ready signal that is returned from the corresponding magnetic disk device upon issuance of the alternative drive select signal are held. The configuration includes a ready signal drop detection circuit consisting of a circuit that determines whether a ready signal drop has occurred based on the state change, and a circuit that holds information on the determination result, which places a burden on the firmware in the device. A drop in the ready signal can be detected reliably and easily without causing a drop in the ready signal, thereby making it possible to prevent the occurrence of the various troubles described above due to the occurrence of a drop in the ready signal.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing the configuration of the ready signal detection circuit in the above embodiment, and Fig. 3 shows the operation of the above embodiment. A time chart showing the signal states of each part in FIG. 2 above for explanation; FIG. 4 is a block diagram showing the conventional configuration of a system having an interface mechanism targeted by the present invention;
FIG. 5 is a diagram showing signals and connection pin numbers of the disk interface mechanism targeted by the present invention. 1... Magnetic disk control device, 21p2t... Magnetic disk device (drive), 3... Data cable,
4...:l 7 C1-7I/sf -fi scale
Pull, 11...Microprocessor (μmp), 12
...Host interface section, 13HDC (hard disk control) section, 14...Dreitz interface section, 15...Ready signal drop detection circuit, 5
1... Control circuit (CNT), 52, 53, 56, 5
1.62.63... andy-to, 54.55...
OR gate, 58°59.60.61...D type flip-flop, 64°65...SR type flip-flop, 66.677...Output puffer.

Claims (1)

[Claims] In a magnetic disk control device that has an interface mechanism that specifies a magnetic disk device using a drive select signal and transfers a control signal to the device, the drive select signal changes to a non-selected state and remains in the state for a certain period of time. means for detecting the drive select signal, means for prohibiting the issuance of the drive select signal at the time of this detection, and issuing an internally generated alternative drive select signal, and means for sending a return signal from the corresponding magnetic disk device upon issuance of the alternative drive select signal. What is claimed is: 1. A magnetic disk control device comprising means for holding a ready signal and determining whether a ready signal drop has occurred based on a change in its state, and means for holding information on the result of this determination.