JPS6297171A - Floppy disk device - Google Patents

Abstract

PURPOSE:To prevent the recording of the wrong data by inhibiting the writing to a floppy disk while the revolution of the floppy disk is unstable and then recording data only when the revolving speed of the disk is stabilized. CONSTITUTION:A timer circuit 2 supplies a revolving speed switch signal 1 from a host controller and delivers the pulse width of the prescribed time as a timer signal 3 at the rise and fall of the signal 1. An index generating circuit 5 supplies the signal 3 and the index pulse signal 4 produced every revolution of a floppy disk to secure an AND and delivers it as a corrected index signal 6. The pulse width of the signal 3 is set larger than the time of an unstable area due to the change of the revolving speed with input of the signal 1. While a host device sends no new write data before the signal 6 is received. Thus the new data is never written as long as the revolution of the disk is unstable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a floppy disk device used by being connected to an information processing device. In particular, the present invention relates to a floppy disk device whose rotational speed is changed according to instructions from a host device.

〔overview〕

In a floppy disk device whose rotational speed is changed according to instructions from a host device, the present invention provides that the floppy disk continues to rotate for a period of time from immediately after the rotational speed is changed until the rotational speed becomes stable. By prohibiting data from being transmitted to the higher-level device, data from the higher-level device is prevented from arriving, thereby preventing the recording of erroneous data.

[Conventional technology]

Conventionally, this kind of rotational speed switching type floppy disk device outputs one index pulse for one rotation of the medium mounted on the disk in response to a rotational speed switching signal from a host controller, and outputs one data. It is designed to write.

[Problem that the invention seeks to solve]

Even if the rotation speed is changed by inputting the rotation speed switching signal from the host device and the subsequent rotation is still in a transition state and is not stable, the device is in a ready state and the host's <Writing is performed by the old signal from device B. In this case, there is a drawback that even if normal data is sent, the rotational speed is unstable so that it is recorded as incorrect data on the medium.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a floppy disk device that prevents normal data from being recorded as erroneous data.

[Means for solving problems]

The present invention provides a floppy disk device equipped with means for switching the rotation speed according to a rotation speed switching signal from a host device, in which the rotation speed switching signal lasts for a predetermined time longer than the time required for the rotation to stabilize when manually applied. By providing a means for generating a pulse to indicate the index pulse and a means for inhibiting transmission of the index pulse to the host device for the duration of this pulse, it is possible to inhibit writing to the floppy disk while the rotation is unstable. Features.

(Function) When the rotation speed is changed, the host device is in a standby state until the rotation of the floppy disk stabilizes, and no write data arrives, so data cannot be written during the period when the rotation is unstable. is never done.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic block diagram of an apparatus according to an embodiment of the present invention. A rotational speed switching signal l coming from a host control device is input to a timer circuit 2. The output of the timer circuit 2 and the index pulse signal 4 are connected to an index generation circuit 5. The index pulse signal 4 is a pulse generated each time the floppy disk rotates. The index generation circuit 5 is an AND circuit, and outputs a correction index pulse signal 6 at its output.

FIG. 2 shows a timing chart of each partial signal in FIG. The timer circuit 2 receives the rotational speed switching signal 1 from the host control device as an input, and outputs pulse widths T1 and T2 of a predetermined time as a timer signal 3 at the rising edge and falling edge of the signal, respectively. The index generation circuit 5 inputs the timer signal 3 and the index pulse signal 4, performs a logical product thereof, and outputs the result as a corrected index signal 6. The pulse widths T1 and T2 of the timer signal 3 correspond to an unstable region 8 in the rotational speed change 7 when the rotational speed switching signal 1 is input.
The pulse width is set to a longer time.

The correction index pulse signal 6 is sent to the host device.

Since the host device does not transmit new write data unless this signal arrives, new data will not be written during a period when the rotation of the Flo-Nobi disk device is unstable.

[Effects of the Invention] As explained above, according to the present invention, even if the rotational speed of the floppy disk is changed, no new writing is performed until the rotational speed stabilizes, and the rotational speed is stabilized. Since recording is performed only after this, it is possible to prevent erroneous data from being recorded.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a timing chart of each partial signal in FIG. 1. l...Rotation speed switching signal, 2...Timer circuit, 3.
...Timer signal, 4...Index pulse signal, 5
. . . Index generation circuit, 6. Correction index pulse signal, 7. Rotation speed change, 8. Rotation speed unstable region.

Claims (1)

[Claims] (1) In a floppy disk device equipped with a means for switching the rotation speed according to a rotation speed switching signal from a host device, the floppy disk drive lasts for a predetermined time longer than the time required for the rotation to stabilize when the rotation speed switching signal is input. A floppy disk device comprising means for generating a pulse, and means for prohibiting an index pulse generated in synchronization with the rotation of the floppy disk from being transmitted to a host device for the duration of the pulse. .