JPH0319013A - Interface circuit for magnetic disk device - Google Patents

Abstract

PURPOSE:To simplify the constitution of an interface circuit by securing the connection of interface cables consisting of 30 pairs of 60 signal lines including fly-back lines of each signal. CONSTITUTION:A magnetic disk device 1 is connected to a controller 2 via the interface cables 3 consisting of 60 signal lines (30 pairs). A 1st group of signal lines are sent only in the single direction of the device 1 from the controller 2. A 2nd group of signal lines are sent only in the signal direction of the controller 2 from the device 1. A 3rd group of signal lines are concerned with the transfer of storage data. Then each signal of a 4th group of signal lines transmits and receives a differential signal. The signals of other groups transmit and receive the TTL unipolar signals. Therefore these signals are paired with the ground lines serving as the signal fly-back lines. As a result, the structure of an interface signal line is simplified and the capacity of an interface circuit is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interface circuit for a magnetic disk drive, and more particularly to interface signal assignment and circuit assignment suitable for simplifying the interface circuit configuration.

[Conventional technology]

Conventionally, the so-called SMD (abbreviation for storage module drive) was used as an interface for magnetic disk devices.
Interface is the most common.

[Problem to be solved by the invention]

The SMD specification interface cable configuration and interface circuit configuration have the drawback of requiring multiple cables and a considerable amount of circuitry.

[Means to solve the problem]

The interface circuit according to the present invention performs device selection control including the magnetic disk device from an external control device, and controls cylinders in the selected device.

At least 6 signal receiving circuits sent for head selection control, data writing/reading control, addresses associated with the control, and at least 1 signal receiving circuit used for exchanging control data.
0 bus signal receiving circuits, a minimum of 8 bus signal sending circuits used for status information sent from the magnetic disk device to an external control device, and a minimum of 2 signals for sending track orientation signals to the control device. The transmitting circuit, the above is a TTL level signal, is a total of two read data and read/reference clock signals by the differential signal transmitting circuit, and two write data and write clock signals by the differential signal receiving circuit. It has a configuration in which 60 signal lines (30 pairs) are housed in a connector.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, in the first embodiment of the present invention, a magnetic disk device 1 and a control device 2 are connected by an interface cable 3 having a total of 60 signal lines (30 pairs). Interface on the magnetic disk device 1 side; Nectar 100
To explain the configuration contents, the first group is a group of signals that are transferred only in one direction from the control device 2 to the device l, and includes an I/F ENABLE signal 101. which indicates the effectiveness of control on the interface cable 3. UNITSELECT TA for selecting and controlling only a designated device from a plurality of magnetic disk devices including the device 1 (see Figure 2)
G signal 102, cylinder in selected device l;
TAG1 signal 103 that specifies any of the control functions such as seek control, head selection, write reading, tree extraction, etc.;
TAG 2 signal 104, TAG 3 signal 105, TAG 4 signal 106 for status information selection, and the UNI
TSELECT TAG, TAGI, TAG2. TAG
3. Consists of signals BUS from BUS OUT BITO 110 to BUS OUT BITO 119, which are combined with the TAG4 signal to select device address, cylinder address, read/write instructions, and status information (see FIG. 5). The second group is a group of signals that are transferred only in one direction from the device 1 to the control device 2, and is a track orientation signal UNIT 5EL.
ECTED140.5EEK ENDl 41, TAG
BUS IN BITO/INDEX 150 to BUS IN BIT 7/PROTECTED 15 which transfers the status information (Fig. 5 (B)) of the device 1 selected by the combination of BUS IN BITO 4 and BUS OUT BITO 119.
It consists of up to 7. The third group relates to the transfer of storage data, and is a combination of a read data signal and a clock signal sent from the device 1 to the control device 2.
READ DATA signal 160 and READ/RE respectively.
The F CLOCK signal 161 and the 4 WRITE DATA signals 170 and W
RITECLOCK signal 171. Fourth
Each signal belonging to the group performs differential shadow signal transmission and reception, and all other signals perform TTL unipolar signal transmission and reception.Therefore, these are paired with a ground line as a signal return line.

Next, the configuration of the magnetic disk device 1 to which the first embodiment is applied will be explained based on FIGS. 2, 3, and 5.

I/F ENABLE signal 101, UNITSELEC
The T TAG 102, the TAGI signal 103 to the TAG4 signal 106, and the BUS OUT BITO 110 to the BUS OUT BIT 9119 are received by the TTL signal receiving circuit 10, gate-controlled, and then sent to each functional block.

The device selection logic circuit 50 connects the I
/F ENABLE, UNIT 5ELECTTAG
Signal and BUS OUT BITO110 to BUS
Unit address (UNIT ADO-2, Figure 5 (A) included in the bus data of OUT BIT4 114
) and a pre-designated device address, and if they match, a UNIT 5-ELECTED signal is sent to a predetermined functional block. The cylinder address register circuit 61 receives the BUS signal by the TAGI signal 103.
OUT BITo 110 to BUS OUT BI
Cylinder address information (CYL) included in T9 119
ADO~9 (see Table 1) is stored and given to the magnetic disk drive circuit 70 as seek information. The head address register circuit 62 receives the BUS signal from the TAG2 signal 104.
OUT BITO110 to BUSOUT B
Head address information (HDA
DO~32 (see Table 1) is stored and provided to the magnetic disk drive circuit 70 as head selection information. The control gate circuit 63 connects the TAG3 signal 105 and EUS OUT B
ITO signal 110 to BUS OUT BIT8 signal 1
By the combination of 18 (see FIG. 5(A)), write/read operations of storage data are mainly decoded and applied to the magnetic disk drive circuit 70. The device selection logic circuit 50 sends a UNIT 5ELECTED signal 140 when selecting a device, and the magnetic disk drive circuit 70 sends a UNIT 5ELECTED signal 140 when a seek operation is completed.
The K END signal 141 is sent out through the TTL transmission circuit 20, respectively. READDATAI 60 and READ
/REF CLOCK161 has READ GATE
During operation, read data and a read clock are sent out through the differential signal transmission circuit section 30, respectively. WRITE on the other hand
WRITE CLOCK signal 170 and W during GATE operation
The write data on the RITE DATA signal 171 is received by the differential signal receiving circuit section 40, sent to the magnetic disk drive circuit 70, and written on the designated track. TAG4
Signal 106 is combined with BUS BIT 9 number 119 to perform a DEVIcE TYPEREQUEST operation or a 5ENSE ERRORSTATUS operation. (5th FgJ(B)) FIG. 3 shows the structure of the interface 3 when a plurality of magnetic disk devices l of the first embodiment shown in FIG. 1 are connected to the same control device 2. FIG. 4(a) shows a case where there is one interface connector 100 on the magnetic disk device 1 side, and FIG. 4(b) shows a case where the interface connector 100 is duplicated. In addition, the last magnetic disk device in, In'
A termination circuit 4 or 4' is mounted thereon.

FIG. 4 is a representative representation of individual detailed circuits of each interface signal transmitting/receiving circuit section based on FIGS. 2 and 3.

〔Effect of the invention〕

As explained above, the present invention has the effect of simplifying the interface signal line by unifying the interface cable, reducing the amount of interface circuitry, and facilitating the simultaneous connection of multiple devices.

[Brief explanation of the drawing]

FIG. 1 is a signal system diagram showing interface signal assignment according to a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a magnetic disk device in blocks according to the first embodiment,
FIG. 3 is an interface system diagram when connecting multiple magnetic disk devices according to the first embodiment, and FIG.
5A and 5B are circuit diagrams showing examples of individual interface circuits based on FIGS. 2 and 3, and FIGS. 5A and 5B are diagrams showing the relationship between pass lines and tags. 1, la, lb, in...magnetic disk device,
2...Control device, 3.3'...Interface signal line, 4,4'...Termination circuit, 1
0...TTL signal receiving circuit section, 11...
・TTL signal reception circuit, 20...TTL signal transmission circuit section, 21...TTL signal transmission circuit, 30
... Differential signal transmission circuit section, 31 ... Differential signal transmission circuit, 40 ... Differential signal reception circuit section, 41 ... Differential signal Receiving circuit, 50...
・Device selection logic circuit, 61...Cylinder address register circuit, 62...Head address register circuit, 63...Fun troll gate circuit,
70...Magnetic disk drive circuit, 80...
・Status multiplexer, 12, 13, 22.2
3...Terminal resistor, 32.33, 44.45...
...Terminal resistance, 42, 43...Limiting resistance.

Claims (1)

[Claims] In the interface with a control device of a magnetic disk device that has multiple cylinders and heads and executes write and read operations of storage data, a minimum of six control signals are transmitted from the control device in one direction only to the magnetic disk device. a TTL level signal receiving circuit that receives a TTL level signal, and a TTL level signal receiving circuit that receives at least 10 data signals that are interlocked with the control signal and are transmitted only in the same direction as the control signal;
TTL that sends at least two status signals that are transmitted only in one direction from the magnetic disk device to the control device;
A level signal transmitting circuit, a TTL level signal transmitting circuit that transmits at least eight data signals that are transmitted only in the same direction as the status signal, read data that is serially transferred bit by bit, and when transferring the read data. two sets of differential signal transmitting circuits that send out read clock signals or reference clock signals when not reading, and write data and synchronization write clock signals that are serially transferred bit by bit from the control device during writing. A magnetic disk drive having two sets of differentially homogeneous signal receiving circuits for receiving signals, and having only one interface cable connection consisting of a total of 30 pairs and a total of 60 signal lines, including a signal return line for each of the signals. interface circuit.