JPS63209068A - Disk detection circuit for floppy disk device - Google Patents

Abstract

PURPOSE:To detect a disk with the constitution of a circuit which is simple and easy to be integrated and to minimize and simplify a whole device by providing an index detection means for outputting (a) detection signal having a specified pulse width. CONSTITUTION:An index sensor detects an index hole formed on the disk and outputs an index signal I of one pulse in one rotation. A monostable multivibrator 10 triggers at the time of the first transition of the index signal I and outputs the pulse signal M having a pulse width which is decided based on CR time constants by a capacitor 11 and a resistor 12. A flip flop 13 outputs an output signal F in high level according to the index signal I and a NAND circuit 14 outputs a disk detection signal D to the control circuit of a disk drive. Thus, the detection of the disk can be securely executed with the constitution of the circuit which is simple and easy to be integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a disk detection circuit for a floppy disk device for detecting whether a disk is inserted into or taken out from a disk drive.

(Prior Art) Conventionally, a floppy disk device is provided with a detector for detecting whether or not a disk (magnetic recording medium) is inserted into a disk drive. A detection signal from this detector is output to a disk drive control circuit (FDMC).

The FDMC outputs a motor-on signal for a disk rotation drive motor (spindle motor) to a motor control circuit, or outputs a READY signal to a controller, based on a detection signal from a detector or the like.

There are various types of detectors, such as a detection method using a mechanical or optical detection mechanism placed near a door (lever) provided in a disk insertion slot of a disk drive. However, in either method, the detection mechanism is complicated, and there are problems such as it is difficult to secure a space for a detector, especially in a small floppy disk device.

(Problems to be Solved by the Invention) In conventional disk detectors, the detection mechanism is complicated and requires a relatively large space for placement within the disk drive. This poses an obstacle to miniaturizing the floppy disk device and simplifying its mechanism.

An object of the present invention is to provide a disk detection circuit for a floppy disk device that can realize miniaturization and simplification of the entire device by enabling disk detection with a simple and easily integrated circuit configuration. There is a particular thing.

E Structure of the Invention] (Means and Effects for Solving the Problems) The present invention is a disk detection circuit using an index signal in a floppy disk 'I device. The disc detection circuit of the present invention includes index detection means for outputting a detection signal having a predetermined pulse width longer than the pulse interval of the index signal in response to the input of the index signal. The apparatus further includes a disk detection means that outputs a disk detection signal after a predetermined period of time after inputting the index signal, and stops outputting the disk detection signal in synchronization with the stop of the output of the detection signal of the index detection means.

With such a configuration, the presence or absence of a disk can be reliably detected using a circuit configuration that can be integrated without requiring a complicated detection mechanism.

(Example) The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a disk detection circuit according to the same embodiment. In FIG. 1, a retriggerable monostable multivibrator (hereinafter referred to as monostable) 10 is triggered at the rising edge of an index signal I, and a capacitor 1
A pulse signal (index detection signal) M having a pulse width determined based on the CR time constant of 1 and the resistor 12 is output. The flip-flop 13 has a clock terminal GK
A high-level output signal @F is output in response to the index signal l input to the . The NAND circuit 14 receives the pulse signal M
and output signal @F as input, and outputs the output signal as a disk detection signal to the disk drive control circuit (FDMC).

Next, the operation of this embodiment will be explained. First, in a floppy disk drive, when a disk is inserted into a disk drive and a door (lever) is closed, a magnetic head is loaded onto the surface of the disk. Thereafter, when the disk rotation motor is driven, the disk is rotated. When the disk rotates, an index sensor (optical system detector) detects an index hole formed in the disk and outputs one pulse of index signal I per rotation. The controller (FDC) can detect the start and end of a track on the disk using the index signal I.

When the index signal I is input, the monostable 10 generates a pulse width T based on a preset CR time constant.
2 pulse signal M is output. The flip-flop 13 is cleared by the pulse signal M from the mono staple 10 and outputs a high level signal F corresponding to the index signal I input to the open terminal CK. That is, the second
As shown in the figure, the flip-flop 13 outputs a signal F that rises in synchronization with the index signal I of the second pulse.

Here, the pulse width T of the output signal M of the mono staple 10 is
2 is set to be a longer period than the pulse interval T1 of the index signal I.

This means that the output signal M of the circuit 10 remains at a high level. The NAND circuit 14 outputs a low level signal as a disk-in signal to the FDMC during a period when the high level signal M and the high level signal F are input. That is, the disc-in signal is a signal instructing the insertion of a disc. FDMC performs RE based on the disk-in signal etc.
The ADY signal will be output to the controller. The controller recognizes from the READY signal that it is possible to read/write data to the disk, and executes the read/write operation.

Next, when the read/write operation is completed and the door is opened, the rotation of the disk is stopped.

Therefore, the input of the index signal Sl is stopped. The monostable 10 outputs a signal M having a pulse width T2 in synchronization with the final index signal I.

That is, the monostable 10 outputs the signal M at a high level for a period T2 and then at a low level. This results in
The output signal F of the flip-flop 13 changes to a low level in synchronization with the signal M of the monostable 10. In response to the output signal F and signal M, the NAND circuit 14 outputs a high level signal. That is, the NAND circuit 14 outputs a high level signal after a period T2 from the final index signal . This high level signal is output to the FDMC as a disk out signal.

FDMC performs READ based on disk out signal etc.
Stop outputting the Y signal. That is, the controller determines that the disc is ready to be ejected from the disc drive, or recognizes that the disc has been ejected.

In this way, a high level signal is output as a disc-in signal after a predetermined period of time after the output of the index signal @I, that is, in synchronization with the second pulse of the index signal I.

Furthermore, a period T2 from the final pulse of the index signal I
Y! Then, a low level signal is output as a disc out signal. Thereby, it is possible to detect the disk inserted into the disk drive and started to rotate based on the index signal 1 immediately after the start of output. Furthermore, based on the final pulse of the index signal I, the status of the disc that can be ejected or has been ejected can be detected.

If the method uses such an index signal,
Insertion and ejection of a disk can be reliably detected without using a conventional mechanical or optical detector. Therefore, it is possible to eliminate the need for a space for arranging a detector for disc detection, which can contribute to miniaturization of the disc drive. Furthermore, since the circuits can be integrated, the mechanism of the disk drive can be simplified.

[Effects of the Invention] As detailed above, according to the present invention, a disk can be detected in a floppy disk device using a simple and easily integrated circuit configuration without using a conventional mechanical or optical detector. can be done reliably. Therefore, it is possible to realize miniaturization and simplification of the entire device as a result.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a disk detection circuit according to an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the embodiment. 10... Monostable multivibrator, 13... Flip-flop, 14... NAND circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Scope of Claims] A floppy disk device including an output means for outputting an index signal of one pulse per rotation in accordance with the rotational operation of the disk, wherein, in response to the input of the index signal, the pulse interval of the index signal is longer than the pulse interval of the index signal. index detection means for outputting a detection signal with a predetermined pulse width; and output of the detection signal of the index detection means for outputting a disk detection signal during a period from the start of output of the first pulse of the index signal to the output period of the next pulse. 1. A disk detection circuit for a floppy disk device, comprising disk detection means for stopping output of the disk detection signal in synchronization with the time of stop.