JPH07337095A - Drive controller for two-phase step motor - Google Patents

Abstract

PURPOSE:To deal with the high speed rotary driving using a microstep control system. CONSTITUTION:A microstep drive circuit generally controls the setting of serial data and generation of strobe signal for each required phase on a hardware configuration comprising a timer circuit 20, a count circuit 27, a phase signal generating circuit 29, and a pattern matching circuit 30. This constitution protects a general control CPT against a load accompanying restriction imposed by the time of a strobe signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-phase stepping motor drive controller for driving a two-phase stepping motor by a microstep control method.

[0002]

2. Description of the Related Art A conventional two-phase stepping motor drive control device of this type will be described with reference to FIG. 2 by taking a facsimile device using a stepping motor as an example.
In this facsimile apparatus, a ROM 3 and a RAM 4 are connected to a CPU 1 for controlling the whole via a CPU bus 2, and various control objects necessary for the facsimile apparatus are provided, for example, via a modem 5 and a binarization IC 6. A scanner 7, a modulation / demodulation IC 8 and a print I / F & direct memory access (DMA) 9 are connected. The modem 5 is connected to the line via a communication control unit (NCU) 10. The printing I / F & direct memory access 9 is connected to a printing device 11 that executes a printing operation.

On the other hand, for example, a two-phase stepping motor 12 is provided for sub-scanning drive in the scanner 7. The stepping motor 12 is, for example, a driver I
The drive currents for the A phase, the / A phase, the B phase, and the / B phase ("/" represents a bar ... The same applies hereinafter) are sequentially controlled by C13. In order to control the operation of the driver IC 13 as described above, the latch 14, the timer 15 and the timing generation circuit 16 are sequentially connected between the CPU bus 2 and the driver IC 13. The timer 1
From 5 the interrupt signal to the CPU 1 at an appropriate timing
It is configured to output INT.

In such a configuration, in order to rotate the stepping motor 12, the CPU 1 sets the step time per motor phase for the latch 14. When this step time is set, the timer 15 is started, and when the time is up, the timing generation circuit 16 instructs the driver IC 13 to switch the phase signal. As a result, the stepping motor 12 is driven by one step. When the timer 15 times out, the interrupt signal INT is given to the CPU 1 to cause an interrupt, and the CPU 1 sets the next step time in the latch 14 again, and repeats the above operation. In particular, such a timer control method is convenient because the software does not need to worry about time when high speed rotation is required.

By the way, in order to reduce the vibration noise of the motor in such a stepping motor drive, in order to rotate the motor with finer precision within one step, as the driver IC 13, for example, as shown in FIG. The microstep driving IC 17 is used as a microstep driving circuit. Various signals as shown in FIG. 3 are input to and output from such a microstep driving IC 17. FIG. 4 is a time chart showing an operation example by microstep drive control using such a microstep drive IC 17.

In these figures, DATAA and DATAB are
Ratio of rotor rotation angle in one step in micro step (stepwise drive current value for 100% current)
Reference ref (%) indicating the phase A, / A,
These are serial data for setting the values of B and / B in the microstep driving IC 17. Here, as an example of the reference ref (%), 0%, 20%, 40%, 5
Examples of 5.5%, 71.4%, 83%, 91% and 100% are shown, but numerical values are not limited to these values. CLOCK is a clock signal for carrying serial data. STROBE latches the serial data in the microstep drive IC 17 to drive the stepping motor 1
2 Actual drive data OUT A, / OUT A, OUT
This is a strobe signal by a pulse signal for outputting B and / OUT B.

In such microstep driving, as shown in the time chart of FIG.
It is necessary to input DATAA and DATAB to the microstep drive IC 17 between the strobe signals to set the reference ref (%). Here, it should be noted that one shift (one step) in the two-phase excitation drive corresponds to eight strobe signals. The conventional microstep control method will be described in more detail while considering such points. FIG. 5 shows a microstep driving IC1.
Strobe signal (STROBE) given to 7, serial data
2 shows a circuit configuration for creating DATAA, DATAB and a clock signal (CLOCK). First, the value (time) of the strobe signal is set by the CPU 1 as CP as shown in FIG.
It is set in the latch 18 (corresponding to the latch 14) via the U bus 2. Then, based on the timer load, the OR circuit 19
When the timer 20 is started through the timer 20 and the timer 20 times out, a strobe signal is output from the carry-out CO of the timer 20. Here, the output of the timer 20 is also given to the latch 21, and the interrupt signal INT is output to the CPU 1 at a timing equivalent to that of the strobe signal. The strobe signal is also given to the OR circuit 19, and the timer 20 is provided every time the time is up.
Is to be restarted clear.

Further, as to the creation of the serial data DATAA and DATAB, each time the CPU 1 is interrupted by the interrupt signal INT, the CPU 1 sets data in the latches 22 and 23 as shown in FIG.・
It is converted into serial data DATAA, DATAB by the serial conversion circuits (P → S conversion circuit) 24, 25 and output. That is, the creation of the serial data DATAA, DATAB is executed by the CPU 1 by setting the data, but this data itself is stored in the ROM 3 or the RAM 4, and any pattern (especially, the reference
ref (%) pattern) is read by the CPU 1 and latched 2
2 and 23.

The clock signal is, for example, a clock generation circuit 2 having a 4CLK configuration that multiplies a clock of 1 MHz by 4 times.
Created through 6.

[0010]

In the case of the conventional microstep control method as described above, as shown in FIG.
The writing of TAA and DATAB is executed by the CPU 1 at the timing of the interrupt signal INT every time the strobe signal is generated. As a result, in the case of a system that requires high-speed rotation, the CPU 1 cannot execute an interrupt, which causes a problem that cannot be applied to high-speed rotation. For example, when the stepping motor 12 is rotated at 3,000 pps (pulses / second), the cycle of the strobe signal becomes about 40 μs as shown in FIG. 6, and within this short time, the interrupt signal INT is generated and DATAA, This is because setting the DATAB is impossible with the current software.

[0011]

A two-phase stepping motor drive control device of the present invention is a two-phase stepping motor drive control device for driving and controlling a two-phase stepping motor using a microstep drive circuit. , A count circuit that repeatedly counts eight strobe signals corresponding to one step of two-phase excitation drive based on the output of this timer circuit, and this count circuit counts eight strobe signals. Phase signal generation circuit that sequentially switches between forward and reverse rotation of the applied voltage for each phase, and 1 for each phase for 100% current
One pattern based on the current count value of the strobe signal by the count circuit and the forward / reverse rotation signal of the voltage output from the phase signal generation circuit by holding the pattern of the stepwise drive current setting value in the step And a drive data conversion circuit for generating actual drive data for the micro-step drive circuit according to the decision output of the pattern matching circuit.

[0012]

The strobe signal whose time is set by the CPU that controls the whole is sequentially measured by the timer circuit, and the output of this timer circuit is repeatedly counted by the count circuit for eight strobe signals corresponding to one step. Information is obtained about what the current strobe signal is in one step. Further, the phase signal generating circuit, which operates every time the counting circuit counts eight strobe signals, can obtain information about the phase at the time of step switching. Based on the output information from the count circuit and the phase signal generation circuit, the pattern matching circuit determines and outputs one pattern from the pattern of the stepwise drive current setting value in one step for each phase for 100% current, It is output to the microstep drive circuit through the drive data conversion circuit. Therefore, since the serial data to be given to the micro step drive circuit is predetermined, it is patterned and stored as random logic in the pattern matching circuit in advance, and one pattern is created based on the current strobe signal and the phase signal. It only needs to be selected and determined, and since it is collectively controlled on hardware, even if the value of the strobe signal is high, C
The control does not impose a burden on the PU and can sufficiently cope with high-speed driving.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. The same parts as those shown in FIGS. 2 to 6 are indicated by the same reference numerals. First, similarly to the case shown in FIG. 5A, a timer (timer circuit) 20 for measuring the value (time) of the strobe signal set in the latch 18 by the CPU 1 and outputting the stove signal is provided. . This timer 20 is L based on the start signal or carry out CO
When the O terminal is loaded, the 1 MHz signal is counted by the value of the strobe signal set in the latch 18,
Carry-out CO is output each time the value is reached. The carry-out CO terminal of the timer 20 is connected to an 8-count timer 27 which serves as a counting circuit. The 8-count timer 27 repeatedly counts the number of strobe signals output from the timer 20 by a rotation method and outputs the current count value as a 3-bit signal of A0 to A2. That is, it outputs the information indicating the number of the strobe signal in the eight strobe signals corresponding to one step of the two-phase excitation drive. Further, the 8-count timer 27 outputs a carry-out CO to the latch 28 every eight counts of strobe signal, and outputs an interrupt signal INT to the CPU 1 via the latch 28 to interrupt each step. Has been done. Here, a phase signal generation circuit 29 for switching the phase (normal rotation / reverse rotation of voltage) based on the carry-out CO of the 8-count timer 27 is provided.

Further, a 32 pattern → 4 pattern conversion circuit 30 which receives the 3-bit signals A0 to A2 from the 8-count timer 27 and the phase signals A and B from the phase signal generation circuit 29 is a pattern matching circuit. Is provided as. The 32 pattern → 4 pattern conversion circuit 30 has eight reference ref (%) (= 32 types) in one step for each of the A phase, / A phase, B phase, and / B phase as information on DATAA and DATAB. The pattern information for specifying the four specific combinations is embedded. That is, the reference ref (%) given to each phase (A phase, / A phase, B phase, / B phase) in the micro step drive changes in 8 steps from 0 to 100%, When viewed with a strobe signal, each reference ref (%) for the A phase, / A phase, B phase, and / B phase is only one combination,
The focus is on identifying 4 patterns out of 32 patterns. In terms of hardware, it is composed of a random logic unit and a selector unit. Therefore,
Every time the 3-bit signal of A0 to A2 output from the 8-count timer 27 changes (every time the strobe signal increases), the random logic in the 32 pattern → 4 pattern generation circuit 30 is suitable for the 3-bit signal value at that time. The pattern of the reference ref (%) is determined and output to the parallel / serial conversion circuits 31 and 32 which are the drive data conversion circuits. At this time, the phase signal generation circuit 2
32 patterns of phase information A and B output from 9 →
The pattern is considered by the selector section in the 4-pattern conversion circuit 30 and is used for pattern selection. The parallel / serial conversion circuits 31, 32 convert the signal output from the 32 pattern → 4 pattern conversion circuit 30 into a microstep driving IC 1.
It is for converting into serial data to be given to 7 and is timing-controlled by the clock of the clock generation circuit 26 as in the case of the parallel / serial conversion circuits 24 and 25.

In such a configuration, the CPU 1 sets the value (time) of the strobe signal in the latch 18. In response to this, the timer 20 is started and the carry-out CO outputs a pulse signal. This pulse signal corresponds to the strobe signal, and the 8-count timer 2
It is sequentially counted by 7. Therefore, 8 count timer 2
The 3-bit signal of A0 to A2 output from 7 indicates the order of the current strobe signal among the 8 strobe signals required for one step, and is output to the 32 pattern → 4 pattern conversion circuit 30. It In the 32 pattern → 4 pattern conversion circuit 30, each time the 3-bit signal A0 to A2 changes (every time the strobe signal increases), a reference ref (%) suitable for it is determined and the parallel / serial conversion circuits 31 and 32 are determined. Output to. Further, in the phase signal generation circuit 29, the 8-count timer 2
Every time 8 counts 8 (every 1 step), the phase is switched and the phase information is output to the 32 pattern → 4 pattern conversion circuit 30 as A and B.

That is, the serial data DATAA and DATAB to be supplied to the microstep driving IC 17 are patterned and stored as random logic in the 32 pattern → 4 pattern conversion circuit 30, and which pattern is to be selected. 8 count timer 27
It may be performed based on the count value (3 bit value consisting of A0 to A2) and the phase information A and B of the phase signal generating circuit 29. Therefore, the value of strobe signal (time)
Is less than 40 .mu.s (equivalent to about 3,000 pps) or less, the CPU 1 is not burdened, so that high-speed rotation drive of 3,000 pps or more can be dealt with without causing a problem of interrupt processing time. That is, in this embodiment, the microstep drive IC 1
Since the data setting related to the serial data DATAA and DATAB given to 7 and the activation generation of the strobe signal are collectively controlled on the hardware configuration as shown in FIG. 1, the CPU 1 sets the value of the strobe signal. Only need be set, and the problem of interrupt processing time does not occur. In particular, even if the value of the strobe signal is 40 μs, if the value of the next strobe signal is set at the time when the interrupt signal INT is generated after 320 μs which is eight times (= 1 step time) has elapsed Since it is good, the CPU 1 can deal with it with a sufficient time margin. The interrupt signal INT in FIG. 4 shows this state.

Further, as shown in FIG. 1, the latch 1
If a D-type latch 33 is added to the subsequent stage of 8 (before the timer 20), the CPU 1 can reserve and set the value of the next strobe signal at an arbitrary timing before the count-up of the 8-count timer 27. Thus, highly flexible control becomes possible. That is, the D-type latch 33 has a function of automatically writing the reserved data to the timer 20 after the 8-count timer 27 counts up (by receiving the carry-out CO signal).

[0018]

According to the two-phase stepping motor drive control device of the present invention, the two-phase stepping motor drive control device is used.
In a two-phase stepping motor drive control device for driving and controlling a phase stepping motor, a timer circuit that measures the time of a set strobe signal and eight strobes corresponding to one step of two-phase excitation drive based on the output of this timer circuit A counting circuit that repeatedly counts the signal component, a phase signal generating circuit that sequentially switches between forward and reverse rotation of the voltage to be applied each time the counting circuit counts eight strobe signals, and one step for each phase for a current of 100%. Holding a pattern of the stepwise drive current set value in the internal circuit, and forming one pattern based on the current count value of the strobe signal by the count circuit and the forward / reverse rotation signal of the voltage output from the phase signal generation circuit. According to the pattern matching circuit that decides and outputs and the decision output of this pattern matching circuit. Since the drive data conversion circuit for generating the actual drive data for the microstep drive circuit is provided, the timer circuit counts the serial data setting and strobe signal activation generation required for the microstep drive circuit. Since the circuit, the phase signal generation circuit and the pattern matching circuit can collectively control the hardware configuration, the CPU that controls the entire circuit only needs to set the value of the strobe signal, and the time of the strobe signal itself is restricted. Since it does not exist, high-speed driving can be realized by microstep control.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a facsimile device for explaining a conventional example.

FIG. 3 is a block diagram showing a configuration example of a microstep driving IC.

FIG. 4 is a time chart showing an operation control example of a microstep control method.

FIG. 5 is a block diagram showing a configuration example of a microstep control portion.

FIG. 6 is a time chart showing a relationship between a strobe signal and an interrupt signal.

[Explanation of symbols]

 12 stepping motor 17 microstep drive circuit 20 timer circuit 27 count circuit 29 phase signal generation circuit 30 pattern matching circuit 31, 32 drive data conversion circuit

Claims (1)

[Claims] 1. A two-phase stepping motor drive control device for driving and controlling a two-phase stepping motor using a micro-step drive circuit, based on a timer circuit for measuring the time of a set strobe signal and an output of this timer circuit. A count circuit that repeatedly counts eight strobe signals corresponding to one step of two-phase excitation drive, and a phase signal generation that sequentially switches between forward rotation and reverse rotation of the voltage applied every time this count circuit counts eight strobe signals Circuit, and a current strobe signal count value by the count circuit and a voltage output from the phase signal generation circuit by holding a pattern of a stepwise drive current setting value in one step for each phase for 100% current Pattern matching circuit that determines and outputs one pattern based on the forward and reverse signals of And a drive data conversion circuit for generating actual drive data for the microstep drive circuit according to the decision output of the pattern matching circuit.