JPS63148896A - Stepping motor driving system - Google Patents

Abstract

PURPOSE:To simplify a driving circuit and achieve a cost reduction by using one shift control means and a unidirectional circulating type shift register. CONSTITUTION:A circulating type shift register 9 is composed of n X m bits in which data indicating start of excitation or continuation of said start, for example, '1' and data indicating end of excitation or continuation of said end, for example, '0' A shift control means 8 controls shift operation of the circulating type shift register 9 by inputting of a shift clock pulse and a signal indicating a direction of rotation. An output port 4 is connected with bit registers r0, r1 of the circulating type shift register 9. Each output of the output port 4 is connected with driving circuits 5, 6 exciting each phase 7A, 7B of a stepping motor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stepping motor drive system suitable for use in printers, plotters, and other various positioning control devices, and particularly to a unidirectional circulating shift register and The present invention relates to a stepping motor drive system that simplifies a control device by allowing rotation in both positive and negative directions by using only one shift control means.

Paper feed, carriage feed,
Stepping motors are often used as control means for positioning control such as character selection, plotter pen feeding, and other various positioning control devices.

Conventionally, in order to control the rotational direction of a stepping motor, data for switching the excitation phase, that is, data such as #1'' that instructs the start or continuation of excitation, and data, for example, data that instructs the end of excitation or its continuation, are used. rz
a 4-bit circular shift register in which ON data is stored; and two shift control means for controlling the shift operation of the circular shift register by inputting a shift clock pulse and a signal instructing a rotation direction. , two output ports of the same number as excitation phases connected to the two consecutive bit registers of the circular shift register, and a drive circuit to which each output of the output ports is connected to excite each phase of the stepping motor. The two shift control means are selected by a signal instructing the rotation direction, and each data of the cyclic shift register is shifted every time a shift clock pulse is input, and then the output port is selected by a read pulse. A stepping motor drive device is known that uses a method of driving each phase by reading out data from the phase shifter.

FIG. 4 is a functional block diagram showing an example of the configuration of main parts of a conventional stepping motor drive device. In the drawing, 1 is a first shift control section, 2 is a second shift control section, 3 is a 4-bit circular shift register, rO to r3 are each of the first to fourth 1-bit registers,
4 is an output port, 4A is a first output port, 4B is a second output port, 5 is an A phase drive circuit, 6 is a B phase drive circuit, 7 is a stepping motor, 7A is an A phase excitation coil,
7B indicates a B-phase excitation coil, and φA and φB indicate phase control signals.

The conventional stepping motor drive device shown in FIG. 4 is a device for driving a two-phase stepping motor 7. As shown in FIG.

The cyclic shift register 3 has a 4-bit configuration and is capable of shifting in 5 directions.

The functions of each part of the stepping motor drive device shown in FIG. 4 are outlined as follows.

First, each 1-bit register r forming the circular shift register 3. -r3 contains switching data for generating each phase excitation signal φA and φB, that is, data such as #I II that instructs the start or continuation of excitation, and data such as II that instructs the end of excitation or its continuation. O
H data is stored.

In addition, in the case of negative logic, rr l, F and 110 g
is given as reverse data.

Here, the data (bo''b3) is in the initial state.

register r. -r3 in a preset order, for example rO, 0, 1, IJ. However, since it is sufficient that this data ('oo"b3) is held in this order, it is also possible to set the state in which this data has been shifted as the initial state.

Selection between the first shift control section 1 and the second shift control section 2 is performed by a rotation direction instruction (switching) signal.

The first shift control unit 1 has a shift control function to move the data (b□-b3) in the 1-bit register rO""r3 constituting the cyclic shift register 3, and uses the shift clock Each pulse input acts to sequentially move the data (bo=b3) stored in each register ro to r3 of the shift register 3 by one bit from the lower to the upper.

The function of the second shift control section 2 is also the same as that of the first shift control section 1.
However, in order to control the rotational direction of the stepping motor 7 in the opposite direction, the shift direction is opposite to that of the first shift control section 1. That is, the circular shift register 3
Each bit data b stored in each 1-bit register rO''''r3. ~b3 is moved by one bit from the upper to the lower.

The output port 4, in the case of FIG. The data from register r(1 and r! is taken out every time a read pulse is input, and the data from register r(1 and r!
. +rl data is loaded.

The first output port 4A of the output port 4 is connected to the A-phase drive circuit 5, and the second output port 4B is connected to the A-phase drive circuit 5.
It is connected to the B-phase drive circuit 6.

The A-phase drive circuit 5 is a drive circuit that drives the A-phase excitation coil 7A of the stepping motor 7, and the B-phase drive circuit 6 is a drive circuit that drives the B-phase excitation coil 7B.

Next, the operation of the conventional stepping motor drive device shown in FIG. 4 will be explained.

First, the rotation operation in the forward direction will be described.

FIG. 5 is a time chart for explaining the operation of the conventional stepping motor drive device shown in FIG. 4 when rotating in the forward direction. The code attached to each signal waveform corresponds to the code position in Fig. 4, and
r Q "" r 3 indicates one-bit registers constituting the circular shift register 3, respectively.

When rotating the motor in the forward direction, the first shift control section 1 is selected, and the data in the circulating shift register 3 is as follows.
One bit is sequentially moved in the positive direction, that is, from lower to upper.

In the initial state, the cyclic shift register 3 has the first
~Fourth 1-bit register r. ~r3 contains data (b
O”b3) are set respectively, in this case bO=O
, bl = O + b2 = 1° b3 = 1.

That is, in this initial state, the first
The bit register rg has data b,=0, and the second bit register r1 has data b,=0.

Therefore, the human phase drive circuit 5 reflects the value of the first 1-bit register rO, and the B-phase drive circuit 6 reflects the value of the second 1-bit register r1, so that φA=0°φB=0. ing.

During this rotation in the positive direction, the first shift control section 1 operates, and when one shift clock pulse is input, each bit register r Q = r constituting the shift register 3
Data b stored in 3. ~b3 is sequentially moved by one bit from the lower to the upper. Therefore, in this state, each bit register rO''r3 of the shift register 3 has bo=1°bl=
Data of OHb2=O+b3=1 will be stored.

After that, a read pulse is input to the output ports 4A and 4B, and the shifted data b.

~b3 is read.

That is, bo=1 is set to the first output port 4A, and b,=Q is set to the second output port 4B.

Therefore, when one clock pulse is input, as shown by φA and φB in FIG. 5, φA=1 and φB=0.

As a result, the stepping motor 7 is rotated in the forward direction by l steps.

The above operations are repeated in sequence for each input of the clock pulse, and the data bo-b3 stored in each bit register ro-r3 of the shift register 3 is changed from the lower to the upper bit by one bit. φA and φ in Figure 5.
It changes as shown in B.

Then, by sequentially repeating such driving operations, the stepping motor 7 is continuously rotated in the forward direction.

Next, the rotation operation in the negative direction will be explained.

In the conventional stepping motor drive system, since the circulating shift register 3 is used, shift control is simple, and it is sufficient to simply reverse the shift of the circulating shift register 3.

In this rotation in the negative direction, the one rotation direction instruction signal causes
When the second shift control section 2 is selected, the data in the bidirectional circular shift register 3 is sequentially shifted by one bit in the reverse direction, that is, from the upper to the lower.

The following FIG. 6 is a time chart for explaining the operation when rotationally driven in the negative direction by the same conventional stepping motor drive method. The reference numerals in FIG. 6 are the same as those in FIG. 5.

The values of the cyclic shift register 3 in the initial state are the same as in the case of positive rotation, and as shown in the leftmost column of the registers in the bottom row in FIG. In this case, data bo-b3 are respectively set in rQ''r3.

bo=Og b1=Ot bz=1+ b3
Suppose that =1− is given.

Therefore, in this initial state, the first bit register rQ of the shift register 3 has data bO=0. The second bit register rl also has data b1=0, and the A-phase drive circuit 5 sets the value of the first 1-bit register r,), and the B-phase drive circuit 6 sets the value of the second 1-bit register r1. Reflecting the values, φA=0°φB=O.

During this rotation in the negative direction, the second shift control section 2 operates, and when one shift clock pulse is input, each bit register r O" r constituting the shift register 3
Data b, to b3 stored in 3 are sequentially moved by 1 bit from upper to lower.

Therefore, in this state, each bit register r of the shift register 3. −r3 has b,=o.

b,=1. Data of b2=l and b3=Q will be stored.

After that, a read pulse is input to the output ports 4A and 4B, and the shifted data b.

~b3, bo and bl are read out.

That is, bo=0 is set to the first output port 4A, and b1=1 is set to the second output port 4B.

In this way, when one clock pulse is input, φA=O, as shown by φA and φB in FIG.
φB=1.

As a result, the stepping motor 7 is rotated by one step in the negative direction.

The above operation is repeated for each input of the Glock pulse, and the data b. φA and φ in FIG. 6 are moved bit by bit.
It changes as shown in B.

Then, by sequentially repeating such driving operations, the stepping motor 7 is continuously rotated in the negative direction.

However, in the conventional stepping motor drive system, two shift control units 1 and 2 are used for shift control.
In addition, since it is necessary to use a shift register having a unidirectional shift function for the circulating shift register 3, the number of parts used increases and the cost increases at the same time. There was this inconvenience.

Therefore, in the stepping motor drive system of this invention,
These disadvantages that occur in the conventional stepping motor drive system include the need for two shift control means for shift control and the need to use a bidirectional circulating shift register, which increases costs. It is an object of the present invention to solve this problem and to enable shifting operations in both directions to be performed using a circuit with a simple configuration and a procedure.

Structure For this purpose, in the stepping motor drive system of the present invention, for example, '1'' is used to instruct the start or continuation of excitation.
data of n×m bits (n
is 3 or 4. m is a positive integer); a shift control means for controlling a shift operation of the circulating shift register by inputting a shift clock pulse and a signal instructing a rotation direction; and a series of the circulating shift registers. The stepper motor is equipped with the same number of output ports as the excitation phases connected to bit registers, and a drive circuit to which each output of the output ports is connected to excite each phase of the stepping motor,
In a conventional stepping motor driving device, each data in the cyclic shift register is shifted every time a shift clock pulse is input, and then read out to the output port by a read pulse to drive each phase. When a shift register capable of shifting in only one direction is used, and the signal instructing the rotation direction is a signal instructing rotation of the motor in one direction, the shift control means uses the shift clock. One shift clock pulse is output in response to one pulse input, and when the signal instructs the motor to rotate in the opposite direction,
By providing a function of outputting (n-1) shift clock pulses in response to one input of the shift clock pulse, when rotating the motor in one direction, one shift clock pulse is output. With the data in the shift register shifted one bit at a time for each input,
When the read pulse is output to the output port to rotate the motor in the opposite direction, (n - 1) shift clock pulses are output to the shift register to change the data in the shift register to (n - 1) bits. In the state after each shift, the read pulse is outputted to the output port to drive the motor rotationally.

Next, embodiments of the stepping motor drive system of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram showing an example of the configuration of essential parts of a stepping motor drive device used when implementing the stepping motor drive method of the present invention. Reference numerals in the drawings are the same as in Fig. 4, and 8
9 indicates a shift control unit, and 9 indicates a unidirectional circular shift register.

As is clear from the comparison between the stepping motor drive device shown in FIG. 1 and FIG. 4, which shows a conventional stepping motor drive device, the drive device shown in FIG. 1 has only one shift control section 8. Only one is provided.

Further, the circular shift register 9 is a unidirectional shift register that can shift only in one direction, and for each input of a shift clock pulse, one direction, for example, from lower to upper
It operates to shift only bits sequentially.

First, the rotation operation in the forward direction will be described. The operation during rotation in the forward direction is similar to that of the conventional stepping motor drive device described above.

FIG. 2 is a time chart for explaining the operation of the stepping motor drive device shown in FIG. 1 when the stepping motor drive system of the present invention rotates in the forward direction.

In the stepping motor drive system of the present invention, the values of the cyclic shift register 9 in the initial state are the same as in the conventional drive system, and as shown in the leftmost column of the bottom register in FIG. Data (bo"b3) is stored in each bit register rQ""r3, bo = O * bt = O
Assume that y bz =1 and b3 =1 are set, respectively.

That is, even in this initial state, the circulating shift register 9
The first bit register rO has data bo=Q, and the second bit register rl has data b1=0.

Then, as shown in FIG. 1, the first bit register r
. is A via the first output port 4A of output port 4.
The phase drive circuit 5 and the second bit register r1 are
The output ports 4 are connected to the B-phase drive circuit 6 via the second output port 4B.

Therefore, in this initial state, the A-phase drive circuit 5 in FIG.
reflects the value of the first 1-bit register r□, and the B-phase drive circuit 6 reflects the value of the second 1-bit register rl, as shown in φA and φB in FIG. ,φA
=0. φB=0.

In this state, when one shift clock pulse is input, the shift control unit 8 shifts the data bo''b3 stored in each bit register r□''r3 of the cyclic shift register 9 from the lower to the upper. Since only one bit is shifted sequentially, the state after the shift is bO=1. bt
=Ot bz =Otb3=1.

Thereafter, a read pulse is input to the output ports 4A and 4B, and the shifted data bO to b3 are read out.

That is, the first output port 4A has b. =1 is set, and b = 0 is set in the second output port 4B.

Therefore, in a state where one clock pulse is input, as shown by φA and φB in FIG.

φA=1 and φB=0.

As a result, the stepping motor 7 is rotated by one step in the forward direction.

Next, when the second shift clock pulse is input,
Again each bit register r of the circular shift register 9 □
-r Data b stored in 3.

~b3 is shifted by 1 bit from lower to upper, and b
0=1. b1=1. b2=O9b3=0.

After that, a read pulse is input to the output ports 4A and 4B, and the shifted data b.

~b3 is read.

In this state, the first output port 4A has φA=1, and the second output port 4B also has φB=1.

In this way, by inputting the shift clock pulse, the data bo-b3 stored in each bit register rO-r3 of the circular shift register 9 is shifted one bit at a time from the lower to the upper, and the data is shifted one bit at a time from the lower to the upper. As shown in the register column at the bottom, data bo and bl are read out to the first output port 4A and the second output port 4B, respectively, and the operation of driving the stepping motor 7 is repeated in sequence. Finally, the stepping motor 7 is continuously rotated in the forward direction.

Next, a description will be given of the operation in the case of rotational driving in the negative direction, which is the most characteristic feature of the stepping motor drive system of the present invention.

As already explained, in the stepping motor drive method of the present invention, only one shift control section 8 is used, and the circulating shift register 9 is a unidirectional shift register that can shift only in one direction. For each input clock pulse, one bit is sequentially shifted from lower to upper.

When rotating in the negative direction, when a signal instructing rotation in the negative direction is input, the shift control unit 8 controls the output port 4.
While one read pulse is input to
b3) are sequentially shifted by 3 bits.

Therefore, in response to one read pulse input to the output port 4, three shift clock pulses are output from the shift control section 8, and the cyclic shift register 9 is shifted three times.

After this 3-bit shift operation, by inputting one read pulse to the output port 4, the data (bo and bx) currently set in the bit registers rO and rl of the shift register 9 are retrieved, and the data (bo and bx) are transferred to the stepping motor 7. 1
Drive step.

The following FIG. 3 is a time chart for explaining the operation when rotating in the negative direction using the stepping motor drive method of the present invention.

Reference numerals in the drawings are the same as in FIG. 2.

Even when rotating in the negative direction, each bit register rO-r3 of the cyclic shift register 9 in the initial state
Assume that the value of is the same as in the previous case of positive rotation. That is, each bit register r.

~r3 is the same as the rotational drive in the forward direction shown in Fig. 2 (therefore, it is also the same as in the case of the conventional drive system)
, each data (b
o=b3) is b,=Q,bt==Q,b2=1. b
It is given as follows: 3=1.

In this initial state, as shown in the leftmost column of the bottom register in FIG. 3, data b and bl in bit registers rO and rl of shift register 9 are bo"0.
, = Q, so the A-phase drive circuit 5 and the B-phase drive circuit 6
Also, reflecting the values of bit registers r□ and rl of the shift register 9, φA=0. φB=0.

In this state, when three shift clock pulses are input, each bit register r O"" r of the shift register 9
Data b0 to b3 of No. 3 are shifted by one bit from the lower to the upper for each input of one shift clock pulse, and are moved by a total of three bits, and are moved four columns from the left in the register in the bottom row of FIG. As shown, bO=O, b1=1.
b2=1+b3=0.

This state in which 3 bits have been moved from the lower to the upper is the same as the state in which 1 bit has been moved from the higher to the lower as shown in the second column from the left in the bottom row of the register in Figure 6 above. is the same as

Thereafter, the shifted data bQ and bl are read out to the first output port 4A and the second output port 4B, respectively.

Therefore, the first output port 4A has φA=0, and the second output port 4B has φB=1.

As a result, the stepping motor 7 is rotated by l steps in the negative direction.

Next, when three shift clock pulses are input, each bit register r Q of the shift register 9 is input again.
r 3 data b. -b3 is 3 bits from lower to upper (i.e. only 1 bit from upper to lower)
shifted, b, = l, b, = 1, bz = Op
bs=O.

In this case, the first output port 4A has φA=1, and the second output port 4B also has φB=1.

In this way, by inputting three shift clock pulses, the data bo-b3 of each bit register rO to r3 of the shift register 9 are shifted one bit at a time by a total of three bits, and the shifted data bo and bl are as follows. 1st output port 4
By sequentially repeating the operation of reading data to A and the second output port 4B and driving the stepping motor 7, the stepping motor 7 is continuously rotated in the negative direction.

In one or more embodiments, the data bo to b3 set in the 4-bit circular shift register 9 have initial values of "Q, 0, 1.IJ".

However, it goes without saying that the initial value may be a value in which "ro, 0, 1, 1" is shifted upward or downward.

Further, the cyclic shift register 9 in this case does not necessarily have to have a 4-bit configuration, but may have a 4m times bit configuration such as 8 bits or 16 bits.

In the case of such a 4m bit configuration, the data to be set (bo=b3) are ro, 0, 1 . IJ will be repeated.

Even when using the cyclic shift register 9 with such a 4m bit configuration, when it is rotated in the opposite direction,
As with the 4-bit configuration, if you shift 3 (=4-1) bits, the result is the same data (bo=b3)
is obtained.

Furthermore, in the previous embodiment, a case has been described in which the two-phase motor is rotated in both positive and negative directions.

However, even when a four-phase motor is rotated in both positive and negative directions using a two-phase excitation force method, the same implementation is possible. In this case, for the excitation phases C and D of the motor, there are also four output ports 4, and the third and fourth output ports 4C24D are added, and a li-ring shift is made to each output port 4G and 4D. Bit registers r2tr3 of register 3 are connected.

Furthermore, the present invention can also be implemented when a four-phase motor is rotated in both positive and negative directions using a one-phase excitation force type.

In this case, the basic data b, -b3 set in the cyclic shift register 9 with a 4m-bit configuration are ro, O,
O, IJ may be used.

Similarly, even when a three-phase motor is rotated in both positive and negative directions using a one-phase excitation force type, the same method can be implemented.

In this case, the basic data b0 to b2 set in the 3m-bit circular shift register 9 are rO, O,
IJ will be used.

In this way, the n-bit configuration (
A circular shift register (n is 3 or 4) and the same number of output ports as the excitation phases connected to consecutive bit registers of the circular shift register are provided, and when rotating in the positive direction, one of the shift clock pulses is provided. Data is read from each bit register by associating one read pulse with each input, and when rotating in the negative direction, one read pulse is applied to (n-1) inputs of the shift clock pulse. If you read data from each bit register by corresponding
A unidirectional circular shift register allows equivalent (substantially) shifting operations to be performed in both directions.

Furthermore, in the case of the stepping motor drive system of the present invention, its control circuit system can easily be implemented as a microcomputer.

That is, a microcomputer chip includes various storage devices such as an accumulator, a register, and a memory.

Therefore, select these various storage devices appropriately.

Since it can be used as a circular shift register and a shift clock can be applied by executing a rotate command, it can be read to an output port by an output command.

In this case, even if a shift or rotate command is only possible in one direction with a relatively inexpensive 4-bit CPU, it becomes substantially possible to perform shift operations in both directions, making it possible to perform complex external operations. There is no need to provide an additional circuit.

In this way, with the stepping motor drive method of the present invention, an equivalent circulating shift register can be realized using a unidirectional circulating shift register.
The stepping motor can be rotated in forward and reverse directions.

As explained in detail above, in the stepping motor drive system of the present invention, data such as "1" indicating the start or continuation of excitation, and data such as II O# indicating the end of excitation or its continuation, are used. is stored in a circular shift register of n×m bit configuration (n is 3 or 4, m is a positive integer), and a shift of the circular shift register is performed by inputting a shift clock pulse and a signal instructing the rotation direction. shift control means for controlling the operation; output ports of the same number as excitation phases connected to successive bit registers of the circulating shift register; and each output of the output ports connected to excite each phase of the stepping motor. A conventional stepping motor drive device, comprising a drive circuit, shifts each data in the cyclic shift register every time a shift clock pulse is input, and then reads it out to the output port using a read pulse to drive each phase. A shift register capable of shifting in only one direction is used as the circulating shift register, and the shift control means receives the shift clock pulse when the signal instructs the motor to rotate in one direction. outputs one shift clock pulse in response to one input of the motor, and outputs one shift clock pulse in response to one input of the shift clock pulse when the signal instructs the motor to rotate in the opposite direction. By providing a function of outputting (n-1) clock pulses, when rotating the motor in one direction, the data in the shift register is shifted one bit for each input of a shift clock pulse. In this state, when the read pulse outputs the data to the output port and rotates the motor in the opposite direction, (n-1) shift clock pulses are output to the shift register to change the data of the shift register to ( In the state after shifting by n-1) bits, the read pulse is outputted to the output port to drive the motor to rotate.

Therefore, according to the stepping motor drive method of the present invention, by using only one shift control means and a unidirectional and inexpensive circulating shift register, two shift registers can be used instead of the conventional one. It is possible to perform a positive/negative (positive/reverse) upward shift operation similar to that using the shift control means and a bidirectional circular shift register, and it is also suitable for microcomputerization.

As a result, paper feed, carriage feed,
This is an advantage in that it simplifies the drive circuit of the stepping motor, which is often used as a control means for positioning control such as type selection, pen feeding of plotters, and various other positioning control devices, and also reduces costs. You can get the same effect.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing an example of the main part configuration of a stepping motor drive device used when carrying out the stepping motor drive method of the present invention, and FIG. FIG. 3 is a time chart for explaining the operation when a motor drive device rotates in the positive direction using the stepping motor drive method of the present invention. FIG. FIG. 4 is a functional block diagram showing an example of the main part configuration of a conventional stepping motor drive device. FIG. 5 is a time chart for explaining the operation when driving. FIG. Figure 6 is a time chart for explaining the operation when rotating in the positive direction in the stepping motor drive device of 2008. Time chart for. In the drawing, 1 is a first shift control section, 2 is a second shift control section, 3 is a bidirectional circular shift register,
rO-r3 is each of the first to fourth ebit registers, 4
is the output port, 4A is the first output port, 4B is the second output port
5 is the human phase drive circuit, 6 is the B phase drive circuit,
7 is a stepping motor, 7A is an A-phase excitation coil, 7
B is a B-phase excitation coil, 8 is a shift control unit, and 9 is a unidirectional circulating shift register. φB Kano 2 Figure diad flock expansion 5 Figure shift flock

Claims (2)

[Claims] 1. For example, “1” to instruct the start or continuation of excitation
data of n×m bits (n
is 3 or 4, m is a positive integer), and a shift control means for controlling the shift operation of the shield circular shift register by inputting a shift clock pulse and a signal instructing the rotation direction. , a number of output ports equal to the number of excitation phases connected to consecutive bit registers of the shield ring type shift register, and a drive circuit to which each output of the output ports is connected to excite each phase of the stepping motor. death,
In the stepping motor driving device, each data in the shield ring type shift register is shifted each time a shift clock pulse is input, and then read out to the output port by a read pulse to drive each phase. The register is a shift register that can be shifted in only one direction, and the shift control means controls one of the shift clock pulses when the signal instructing the rotation direction is a signal instructing the motor to rotate in one direction. One shift clock pulse is output in response to the input of the shift clock pulse, and when the signal instructs the motor to rotate in the opposite direction, a shift clock pulse is output in response to the input of one of the shift clock pulses. It has a function to output (n-1) pieces of
When the data in the shift register is shifted one bit at a time for each input, the data is output to the output port by the read pulse, and when the motor is rotated in the opposite direction, a shift clock is sent to the shift register. Pulse (n
-1) data of the shift register is output (n-
1) A stepping motor drive method, characterized in that after shifting bit by bit, the read pulse is output to the output port to drive the motor rotationally. 2. In the stepping motor drive system according to claim 1, the stepping motor is a two-phase motor, the circulating shift register has a 4-bit configuration, and
Consecutive 2-bit registers of the cyclic shift register are connected to two output ports, and when the motor is rotated in one direction, the shift control means controls the shift control means for each input of the shift clock pulse. Shifting the data in the register one bit at a time and outputting it to the output port,
To rotate the motor in the opposite direction, three shift clock pulses are output to the shift register to shift the data in the shift register by three bits, and then output to the output port to drive the motor rotation. A stepping motor drive system that is characterized by the following.