JPH0630706U - Encoder counter - Google Patents

Abstract

(57) [Summary] [Purpose] The phase advance of the A-phase and B-phase signals from the rotary encoder is determined to obtain the rotation direction and rotation angle. [Structure] Based on which edge is detected in the main control CPU and which edge is detected, and the result of the exclusive OR of the states of the respective phases when the edge is detected one time before,
The direction of rotation is obtained by determining which phase is leading, and which is leading,
The rotation angle is obtained from a counter that counts up or counts down for each edge.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an encoder counter, and particularly to detection of a steering angle in an automobile.

[0002]

[Prior art]

 In TCS (Traction Control System) in automobiles, the steering angle sensor is used to obtain information about the steering angle of the steering wheel, but conventionally, the input from the steering angle sensor is a dedicated device (as shown in Fig. 3). Counting was performed using an encoder counter, for example, an IC manufactured by NEC; μPD4701), and the CPU received the data from the device through the bus line by sampling at a constant cycle.

In the dedicated device, due to the input two-phase encoded signals, as shown in FIG. 4, for example, when the A phase is the advanced phase, the direction is left, and when the B phase is the advanced phase, the direction is changed. The judgment was made and the angle was counted by the counter.

[0004]

[Problems to be solved by the device]

 The conventional encoder input method requires a dedicated device (encoder counter), and a bus line must be connected to the outside in order to communicate between the dedicated device and the main control CPU.

Therefore, an object of the present invention is to provide an encoder counter which can be realized by using only a main control CPU without using a dedicated device and without exposing a bus line to the outside of the CPU.

[0006]

[Means for Solving the Problems]

 Therefore, in order to achieve the above-mentioned object, the present invention inputs an A-phase and B-phase pulse signal obtained by a rotary encoder and detects an edge of each phase, and an edge detecting means and an edge detecting means. A storage unit that stores the state (Hi or Lo) of each phase at the time of detection, and a phase advance that determines from the contents of the storage unit whether the phase A or the phase B is in advance when an edge occurs. The encoder counter is characterized by comprising a judging means.

[0007]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS. Figure 1 is a block diagram of this proposal. The encoder counter 9 of the present invention is provided in the CPU for main control, and can detect the rising and falling edges of the pulse signals of phase A 2 and phase B 3 output from the rotary encoder 1 and out of phase by 90 °. Detection means 4 and 5, a phase advance determination means 6 for determining which signal is in advance each time an edge is detected, and a memory for storing the state of each phase at the time of the previous edge detection. 7 and a counter 8 that counts up when the A phase is in advance and counts down when the B phase is in advance.

Further, the phase advance determination by the phase advance determination means 6 is performed in the following procedure.

When the edge of the A phase is detected, the following processing is performed by the phase advance determination means 6a connected to the A phase signal. First, the exclusive OR of the states of both phases stored when one of the edges is detected one time before from the memory 7 is taken. When the result is "0", the A phase is judged to be the leading phase. , The counter 8 is counted up, and when it is "1", the B phase is judged to be in advance, and the counter 8 is counted down. At the same time, the state (Hi or Lo) of each phase at that time is stored in the memory 7.

Similarly, when the edge of the B-phase is detected, the phase-judgment means 6 b connected to the B-phase signal takes the exclusive OR of the states of both phases stored in the previous process, When the result is "1", the A phase is counted as the advanced phase and the counter 8 is counted up. When the result is "0", the B phase is counted as the advanced phase, and when the counter 8 is counted down, it is simultaneously stored in the memory 7. The state of each phase at that time is stored. The processing in 6a and 6b is shown in FIG.

By reading the value of the counter 8 thus counted, the rotation direction and angle of the rotary encoder 1 can be obtained.

[0012]

[Effect of device]

 As described above, since the present invention realizes the encoder counter inside the main control CPU, the encode signal is directly fetched into the CPU without using a dedicated device, and the interrupt processing is performed to detect the direction of each edge of each signal. Since discrimination and counting are performed, the data is updated in real time and more accurate control is possible.

Further, since there is no need for a bus line extending from the CPU to the outside, the device can be downsized and the cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a phase advance determination means 6a, 6 connected to each phase in FIG.
It is a figure which shows the process in b.

FIG. 3 is a block diagram showing a configuration of a conventional technique.

FIG. 4 is a diagram showing an operation of a conventional technique.

[Explanation of symbols]

 1 rotary encoder 2 A phase 3 B phase 4 A phase edge detection device 5 B phase edge detection device 6 leading phase determination device 6a A phase 6b B phase 7 memory 8 counter 9 encoder counter

Claims (1)

[Scope of utility model registration request] 1. An edge detecting means for inputting pulse signals of A phase and B phase obtained by a rotary encoder to detect an edge of each phase, and a state (Hi or Lo) of each phase is stored at the time of edge detection. An encoder counter, comprising: a storage means for storing the stored information; and a phase advance determination means for determining which of the A phase and the B phase is advanced when an edge occurs based on the content of the storage means.