JPH0576714B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ready signal generation device for a magnetic disk.

[Prior Art] The ready signal of a magnetic disk is used to check whether the magnetic disk is in a ready state when a host computer that controls the magnetic disk reads information from or writes information to the disk. used to determine. In other words, the ready state of the magnetic disk indicates a state in which the disk is securely inserted and is rotating normally.

Conventionally, as a device for generating such a ready signal, one that utilizes an index signal obtained by detecting an index hole on a disk is known. That is, the index signal is generated every time the disk rotates once, and as shown in FIG. 4, for example, it is generated once every 200 ms with a pulse width of about 5 ms.

For example, the one shown in FIG. 5 uses two D-type flip-flops 1 and 2, and a drive from the host.
A Select (drive select) signal is input, and a Ready signal is generated by counting the Index signal twice in this state.

The one shown in Fig. 6 uses two D-type flip-flops 1 and 2 and one retrigger type one-shot multivibrator 3, and the index signal is changed into two when the period of the index signal is approximately constant. A Ready signal is generated by counting the number of times.

[Problems to be Solved by the Invention] However, in the case of the one shown in Fig. 5, the Ready signal is generated when the Index signal is counted twice even if the disk is not in a normal rotation state, so the disk does not rotate when the motor starts. There was a risk that information would be written or read in a normal state.

In addition, in the case of the one in Figure 6, the Index signal is counted twice and the Ready signal is generated after the disk rotation becomes normal, so there is a problem that it takes time to start writing and reading information when starting the motor. It was hot.

This invention was made to solve this problem, and it is possible to generate a Ready signal after the disk is reliably in a normal rotation state.
Moreover, it is an object of the present invention to provide a ready signal generation device for a magnetic disk that can quickly generate a ready signal.

[Means for Solving the Problems] The present invention includes a detection means for detecting the rotation period of a spindle motor, and a state reversal means for alternately reversing two states in response to the rotation period detection output from the detection means. , when the state reversing means is in one state, the timer interrupt is enabled in response to the rotation period detection output from the detecting means to start the counting operation of the timer counter, and when the state reversing means is in the other state, the detecting means A timer control means reads out the count value of the timer counter in response to the rotation period detection output from the timer, and the timer value read by the timer control means is compared with preset upper and lower limit values, and the timer and means for outputting a ready signal when the value is between an upper limit value and a lower limit value.

[Operation] In the present invention having such a configuration, when the spindle motor rotates, its rotation period is detected, and the state of the state reversing means is alternately reversed in response to the rotation period detection output. Then, in response to the rotation period detection output when the state reversing means is in one state, a timer interrupt is enabled and the timer counter starts counting. Further, the count value of the timer counter is read out in response to the rotation period detection output from the detection means when the state reversing means is in the other state. Then, when the read timer value is between the upper limit value and the lower limit value, a ready signal is output.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, 11a, 11b, and 11c are Hall elements, and 12a, 12b, and 12c are Hall amplifiers for the Hall elements 11a, 11b, and 11c, respectively. The coils 13a, 13b, 13c of the spindle motor, 14a, 14b, 14c are output amplifiers that control the coils 14a, 14b, 14c, respectively. Each of the Hall elements 11a, 1
The outputs of 1b and 11c are each hall amplifier 12
Matrix circuit 15 via a, 12b, 12c
The output amplifiers 14a, 14b, and 14c are selectively switched by the amplification control section 16.

A frequency generator 17 serves as a detection means for detecting the rotation period of the spindle motor, and detects the rotation speed of the spindle motor. The output from this frequency generator 17 is supplied to a zero cross detector 19 via an FG amplifier 18. The zero-cross detector 19 shapes the waveform of the input signal and supplies it to the comparator 20 as well as to the microprocessor 21 as a TACH signal. on the other hand,
An oscillator 22 is provided, and a signal from the oscillator 22 is supplied to the comparator 20 as a reference signal via a frequency divider 23.

The comparator 20 compares the frequency corresponding to the motor rotation speed from the zero cross detector 19 with the frequency divider 2.
3, and the comparison output is sent to the integrator 24, control amplifier 25 and AND gate 2.
6 to the amplification control section 16.
The opening and closing of the AND gate 26 is controlled by a start/stop signal from the microprocessor 21. The amplification control section 16 controls each output amplifier 14a, 1 by inputting the comparison output.
Controls the switching timing of 4b and 14c.

The microprocessor 21 receives the TACH signal and, as shown in FIG. 2, performs external interrupt processing as shown in FIG. 3 at the rising edge of the signal. This external interrupt first saves the program counter, stack pointer, general purpose registers, and accumulator in sequence. In this state, it is next checked whether the TACH flag, which is state inversion means, is set. If the TACH flag is not set, it is determined that this is the first TACH signal input, and the flag is set, and the comparison counter and timer counter are set to zero.
In this state, timer interrupts are enabled and the timer counter is started. Then, the general-purpose register, accumulator, stack pointer, and program counter are sequentially restored, and the process returns to the main routine.

If the TACH flag is set when the TACH signal is input, it is determined that the TACH signal is input for the second time, and the count value of the timer counter is read. (Timer control means) Next, compare the read count value with the preset lower limit value and upper limit value, and when the count value is greater than or equal to the lower limit value and less than the upper limit value,
Outputs Ready signal. Further, when the count value is below the lower limit value or above the upper limit value, the output of the Ready signal is controlled to be stopped. Finally, the TACH flag is reset, the general-purpose register, accumulator, stack pointer, and program counter are sequentially restored in the same manner as the first time, and the process returns to the main routine.

In the embodiment of the present invention having such a configuration, when the spindle motor rotates, a TACH signal corresponding to the rotation period is generated, and an external interrupt is generated in the microprocessor 21 when this signal rises. This external interrupt causes the timer counter to start counting. When the second external interrupt occurs, the count value of the timer counter is read and it is checked whether the count value is between a preset upper limit value and a lower limit value. The Ready signal is generated only when the count value is between the upper limit value and the lower limit value.

Therefore, when a disk is set in the spindle motor and rotation is started, the rotation of the spindle motor becomes normal and the count value of the timer counter falls between the upper limit value and the lower limit value.
Since the Ready signal is generated, there is no problem in that the Ready signal is generated before the rotation reaches normal rotation. Further, when the spindle motor starts rotating normally, a ready signal is immediately generated by an interrupt, so that information can be written or read quickly.

Also, since the internal timer is used after an external interrupt is generated using the TACH signal for motor control, special circuits such as flip-flops and one-shot multivibrators are not required as in the case of counting the Index signal. do not.

[Effects of the Invention] As detailed above, according to the present invention, a ready signal for a magnetic disk can be generated which can generate a ready signal after the disk is reliably in a normal rotation state, and which can generate the ready signal quickly. A signal generator can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of this invention.
Figure 2 is a waveform diagram showing the TACH signal and the counting operation period of the internal timer, Figure 3 is a flowchart showing the microprocessor's external interrupt processing, Figure 4 is a waveform diagram showing the index signal, and Figure 5. and FIG. 6 are circuit diagrams showing a conventional example. 13a, 13b, 13c...Motor coil, 1
7...Frequency detector, 19...Zero cross detector, 2
1...Microprocessor.

Claims (1)

[Claims] 1: a detection means for detecting the rotation period of the spindle motor; a state reversal means for alternately reversing two states in response to the rotation period detection output from the detection means; In response to the rotation period detection output from the detection means, a timer interrupt is enabled and a timer counter starts counting, and when the state reversing means is in the other state, in response to the rotation period detection output from the detection means. A timer control means for reading out the count value of the timer counter, and a timer value read by the timer control means is compared with a preset upper limit value and a lower limit value, and the timer value is determined to be between the upper limit value and the lower limit value. 1. A ready signal generating device for a magnetic disk, comprising means for outputting a ready signal when the value is between.