JP2908097B2 - Floppy disk device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floppy disk drive and, more particularly, to a method for detecting an index device and adjusting an index signal timing.

[0002]

2. Description of the Related Art A conventional floppy disk drive will be described with reference to the drawings. FIG. 4 is a diagram showing an index sensor for detecting an index position. The index sensor 1 includes a phototransistor 1a and a light emitting diode 1b.

FIG. 5 is a diagram showing an index position detecting method. An index signal is generated when an index hole 7 serving as an index identification hole provided in a floppy disk 6 passes through an index sensor 1 by rotation of the floppy disk. I do. The timing at which the index signal is generated is performed by adjusting the mounting position of the index sensor 1 within a predetermined range (W). FIG. 6 shows an index signal when the index sensor position is moved to each of the positions A, B, and C.
As described above, when moving in the B direction, the timing of the index signal is advanced, and when moving in the C direction, the index signal is conversely delayed.

[0004]

As described above, in the conventional floppy disk device, the timing adjustment of the index signal is performed by mechanically moving the mounting position of the index sensor 1, so that the adjustment is not performed. It was difficult. Also, when the moving direction of the magnetic head is inclined with respect to the radial direction of the floppy disk, the timing of the index signal on the outer track and the inner track is different, but the index signal on the conventional floppy disk is common to all the tracks. Therefore, in some cases, it is impossible to adjust all tracks with the index sensor at a predetermined timing.

An object of the present invention is to provide a floppy disk drive which facilitates the timing adjustment of an index signal and suppresses a change in index signal timing depending on a track position.

[0006]

According to the present invention, there is provided a floppy disk drive having an index output from an index sensor.
The delay time of the index signal, and the index signal
A first delay circuit for determining the pulse width of the first
The index having a delay amount larger than the delay time of the road
Adjust the pulse width of the signal, and
A second delay circuit for determining a pulse width;
Identifies the inner and outer circumferences of the disc and outputs a track selection signal
Based on a track counter and the track selection signal
The output of the first delay circuit or the output of the second delay circuit
And having a selector for selecting the output.

Also, the index sensor outputs
Pulse width t2a triggered by the leading edge of the index signal
And a first pulse generator for outputting a pulse signal of
After the pulse signal of pulse width t2a output from the pulse generator
A pulse signal having a pulse width t2b is output using the edge as a trigger.
Said first delay circuit having a second pulse generator,
A pulse width t using the leading edge of the index signal as a trigger
3a (t3a> t2a) to output a pulse signal
Pulse width output by the pulse generator and the third pulse generator
The pulse width t3 is triggered by the trailing edge of the pulse signal t3a.
b (t3b = t2b).
A second delay circuit having a pulse generator;
Identify the track number of the disc and
Identifies the inner and outer circumferences of the floppy disk as
When the inner track is identified, the inner track selection signal is
Output outer track selection signal when outer track is identified
A track counter and the track counter outputs
Before the track selection signal is the inner track signal
Selecting the output of the first delay circuit and selecting the track
When the selection signal is the outer peripheral track signal, the second delay
Select output of extension circuit and output as index signal
And an output selector .

[0008]

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.
The index sensor 1 for detecting the index position is composed of a phototransistor 1a and a light emitting diode 1b. As shown in FIG. 2, the floppy disk rotates and the index hole 7 passes through the index sensor 1 to generate a pulse signal. Is output.

The output of the index sensor 1 is input to a first delay circuit 2 and a second delay circuit 3. The first delay circuit 2 includes two monostable multivibrators 2a and 2b. The monostable multivibrator 2a sets the delay time of the pulse signal of the index sensor 1 to t2a, and the monostable multivibrator 2b sets the pulse width of the index signal. t2b is determined, and the delay time t2a of the monostable multivibrator 2a can be adjusted by the variable device 2c.

The second delay circuit 3 is composed of two monostable multivibrators 3a and 3b, like the first delay circuit 2, and the monostable multivibrator 3a calculates the delay time t3a of the pulse signal of the index sensor 1, The monostable multivibrator 3b outputs the pulse width t of the index signal.
3b is determined and can be adjusted by the variable device 3c having the delay time t3a of the monostable multivibrator 3a.
Outputs of the monostable multivibrators 2a and 3b are input to the selector 5 as outputs of the first delay circuit 2 and the second delay circuit 3, respectively.

The selector 5 selects one output signal of the two delay circuits 2 and 3 in accordance with the output of the track counter 4 and outputs it as an index signal to a subsequent circuit. Here, the track counter 4 recognizes the track number and sets “H” and “L” with a certain track as a boundary.
It has a function of outputting a digital signal for switching between.

Next, the operation of the present embodiment will be described with reference to the waveform diagram shown in FIG. The output signal S1 of the index sensor 1 is input to the first delay circuit 2 and the second delay circuit 3. In the first delay circuit 2, the monostable multivibrator 2a outputs the output signal S1 of the index sensor 1.
Pulse signal S2 of pulse width t2a triggered by the leading edge of
a is generated and input to the monostable multivibrator 2b. The monostable multivibrator 2b generates a pulse signal S2b having a pulse width t2b triggered by the trailing edge of the pulse signal S2a, and outputs the pulse signal S2b to the selector 5.

In the second delay circuit 3, similarly to the first delay circuit 2, the monostable multivibrator 3a outputs the signal S
A pulse signal S having a pulse width t3a triggered by the leading edge of 1
3a, and the monostable multivibrator 3b outputs the signal S
A pulse signal S3b having a pulse width t3b triggered by the trailing edge of 3a is output to the selector 5.

Here, t2a and t3a are the delay times of the index signal with respect to the index sensor output, and t2a
b and t3b are times for determining the index signal pulse width. The delay times t2a and t2b can be changed by variable devices 2c and 3c provided in the monostable multivibrators 2a and 2b.

The variable devices 2c and 3c are used to adjust the index signal at a predetermined timing. One of the variable devices is used for adjusting the timing of the index signal on the outer track, and the other variable device is used for adjusting the index signal on the inner track. For timing adjustment. At this time,
The index sensor 1 is fixed at a position where the timing of the index signal is advanced (direction B in FIG. 5), and adjusts the timing by delaying the index signal by a variable device.

The output signals S2b and S3b of the delay circuits 2 and 3 adjusted for the inner circumference and the outer circumference are output to the selector 5. The selector 5 selects the signal S2b when the output voltage of the track counter 4 is at the "L" level, and selects the signal S3b when the output voltage is at the "H" level, and sends it to the subsequent stage as an index signal. Here, the track counter 4 recognizes the track number and switches between “H” and “L” on the inner circumference and the outer circumference with a predetermined track as a boundary, and switches the “H” and “L”.
Output to

[0018]

As described above, according to the present invention, the timing of the index signal is electrically adjusted by using the variable device, so that the operation becomes easy and the adjustment can be automated. Also, the timing of the index signal in the outer track and the inner track may be different due to the inclination of the moving direction of the magnetic head with respect to the radial direction of the floppy disk. By having an index adjustment mechanism independent of the track and by switching the timing of the index signal between the inner circumference and the outer circumference with the predetermined track as the boundary,
The timing of the index signal can be adjusted to a predetermined timing in all tracks.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing index position detection using the index sensor shown in FIG.

FIG. 3 is a signal waveform diagram in each section of the embodiment shown in FIG.

FIG. 4 is a diagram showing a conventional index sensor.

5 is a diagram showing a conventional index position detection using the index sensor shown in FIG.

FIG. 6 is a signal waveform diagram of the conventional index position detection method shown in FIGS. 4 and 5.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Index sensor 1a Phototransistor 1b Light emitting diode 2, 3 Delay circuit 2a, 2b, 3a, 3b Monostable multivibrator 2c, 3c Variable device 4 Track counter 5 Selector 6 Floppy disk 7 Index hole W Index sensor adjustment range

Claims (2)

(57) [Claims] 1. An index output by an index sensor.
Adjusting the delay time of the index signal,
A first delay circuit for determining a pulse width of the signal, and a delay amount larger than a delay time of the first delay circuit.
Adjust the pulse width of the index signal, and
A second delay circuit for determining the pulse width of the multiplexed signal, and a track selection by identifying the inner and outer circumferences of the floppy disk
A track counter for outputting a signal, and an output of the first delay circuit based on the track selection signal.
Force or select to select the output of the second delay circuit
Floppy disk drive and having data and, a. , 2. The output of said index sensor.
The pulse width t2a is triggered by the leading edge of the dex signal as a trigger.
A first pulse generator for outputting a pulse signal and a first pulse
The trailing edge of the pulse signal of pulse width t2a output from the generator is
A pulse signal having a pulse width of t2b is output as a trigger.
The first delay circuit having two pulse generators, and a pulse width t triggered by a leading edge of the index signal as a trigger.
3a (t3a> t2a) to output a pulse signal
Pulse width output by the pulse generator and the third pulse generator
The pulse width t3 is triggered by the trailing edge of the pulse signal t3a.
b (t3b = t2b).
The second delay circuit having a pulse generator and a predetermined top
The inner and outer circumferences of the floppy disk with the rack as the boundary
Identify and identify the inner circumference when the inner track selection signal
And an outer track selection signal when the outer circumference is identified.
And the track selection signal output by the track counter is
When the signal is the inner track signal, the output of the first delay circuit is output.
Force, and the track selection signal is
Select the output of the second delay circuit when the
Floppy disk drive according to claim 1 and having an output selector for outputting the index signal, the.