JPS5864542A - State change detection system - Google Patents

Abstract

PURPOSE:To detect rapidly and to reduce a load on software, by adding a fall detecting one-shot circuit to the output side of an OR circuit, and making a comparison with data preceding to reading once a successive state change ends. CONSTITUTION:The output of a process 1 is applied to the rise detecting one- shot circuits 3 and 5, and fall detecting one-shot circuits 4 and 6 of a state change detecting circuit II, and they outputs pulse signals as rise detectng signals and fall detecting signals, which are ORed by OR circuits 7 and 8 respectively. The outputs of those circuits 7 and 8 are applied to fall detecting one- shot circuits 9 and 10, which output fall state change detecting signals. Those detecting signals are supplied to the interruption input device of a computer controller III, and a previous state signal is applied to the digital input device of the device III; when a successive state change ends, a comparison with data before reading is made to realize speedy detection and a reduced load on software.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a state change detection method, and more particularly to a state change detection method for an input signal in a computer control system.

In this type of state change detection method, it is desirable that state changes can be detected quickly and reliably.

When detecting state changes of a large number of input signals from a process in a computer control device, if all points are manually input to the input device, that is, if interrupt lines can be used for all signal lines, it is possible to detect state changes on a certain signal line. This is good because if a change occurs, an interrupt will be activated and the process to change up or down can be performed immediately, but this is generally not possible because the number of interrupt points in a computer control device is limited.

Therefore, the Oγ (logical sum) of the state change detection signal of the input signal
, and input it to the interrupt input device, and the interrupt that changed at that time works, but since it is not possible to tell which one has changed by itself, separately input the status signal to the digital input device in the program, and then check which one has changed. When the state change detection signal is received, the software reads the state signal and compares it with the data from f+tl to detect the input that caused the state change.

As this type of state change detection method, a circuit block diagram configuration as shown in FIG. 1 is known.

In Figure 1, 1 is the process, ■ is the state change detection circuit,
I is a calculation control device, 1 and 2 are input signals, 6 and 5 are rising detection one-shot circuits, 4.6 are falling detection one-shot circuits, and 7 and 8 are OR circuits. Gold input signal 1
and 2 are made into pulse signals by large rising detection one-shot circuits 3 and 5 and falling detection one-shot circuits 4 and 6, and these rising detection signals and falling detection signals are put into OR circuit 7.8 and ORed. The outputs are taken and sent to the interrupt human-powered device of the calculation control device (2) as a rising state change detection signal and a falling state change detection signal of the state change detection circuit 11, respectively. Also, the signals of waveforms A and D in Fig. 2 are as follows:
It is sent as a status signal to the digital input device of the calculation control unit (2).

After receiving the first interrupt input, the calculation control device (2) uses software to read the status signal and compare it with previous data to detect the input signal that caused the status change.

Figure 272 is a signal waveform diagram for each part of Figure 1, and shows when the state change is at one point (on the left) and when two points overlap (on the right).

In Figure 2, A and D are the waveforms of human input signals 1 and 2, B and C are the rising and falling pulses of waveform A, F are the rising and falling pulses of the waveform, and G and H are the waveforms. Waveforms B and E, c and F
The output pulse obtained by ORing 0 and H is input as an interrupt manual signal on the computer side.

In this method, when a state change occurs at a signal at one point, the calculation control device (2) receives a state change detection signal at the rising edge of signal C) at point AA in Figure 2, and sends it to points A and B. The state signals A and D are compared with the data before reading to detect a signal that has changed state.

However, if a state change occurs at two or more signals overlapping as shown on the right side of Figure 2, the calculation control device
receives a state change detection signal at point AO when signal a rises by detecting the rise of signal A, and detects state change detection signal A and D at point AD.
is read and compared with previous data to detect signals that have changed state.

Therefore, in this case, the only signal that can detect a state change is A.

Therefore, in the calculation control device
) at the timing of point A.

It is necessary to compare D with the data before reading and detect a signal that has changed state.

In other words, if state changes overlap, only the state change that occurred in the first one will be found, so if you wait a little longer, you will find another state change. Of course, you can tell from the result whether or not the state changes overlap, so even if they do not overlap, the process will be executed twice.

Therefore, there are disadvantages in that the state signal cannot be read and compared with previous data for a certain period of time after a state change is detected, and that additional software is required to measure a certain period of time.

In this invention, in consideration of these points, when a series of state changes is completed, it is possible to perform a comparison with the data before reading, thereby quickly detecting a state change and reducing the software load. This provides a detection method.

Figure 6 is a circuit block diagram showing an embodiment of the present invention.
The parts corresponding to Figure 1 are indicated by the same reference numerals, and are obtained by adding falling detection one-shot circuits 9 and 10 to the output sides of OR circuits 7 and 8 of the conventional circuit shown in Figure 1. Similarly to Figure 2, Figure 4 is a signal waveform diagram for a large portion of Figure 3, showing the case where the state change is at one point (on the left) and the case where two points overlap (on the right). In Figure 4, A and D are the input signal waveforms.

A, are the rising and falling pulses of waveform A, O, and force are the rising and falling pulses of the waveform generator, K, and KE are the output pulses obtained by ORing waveforms A, O, and force.

This is a one-shot circuit for detecting falling waveforms.9゜10
The signal becomes an output (rising/falling state change detection signal) and is sent to the interrupt input device of the calculation control unit 111.

In addition, the signals of waveforms A and D are used as status signals by the calculation control device -6= It is sent to the ff1I digital input device.

In such a circuit configuration 1, input signals 1 and 2 are converted into pulse signals by rising detection one-shot circuits 3 and 5 and falling detection one-shot circuits 4 and 6, respectively, and these rising detection signals are The OR circuits 7 and 8 perform an OR operation on the falling detection signals, and the signals are sent to the interrupt input device of the calculation control unit via the falling detection one-shot circuits 9 and 10.

Therefore, in this case, the calculation control device does not measure a certain period of time after receiving the state change detection signal, but immediately reads the state signal using software, compares it with previous data, and detects the input signal that caused the state change. There is.

To explain this further, in this method, when a state change occurs at a signal at one point, the calculation control device detects the state change at the rising point BA of the signal, as shown in the case on the left side of Figure 4. After receiving the signal, the state signals A and D are read at the BE point and compared with previous data to detect a signal that has changed state.

Also, the state change is 2. If this happens with a signal of 1 or more, the calculation control device (2) receives the state change detection signal at the rising edge of the signal at point BC, and changes to signal A at point Be.

The input signal that has changed state is detected by comparing the current state with the previous data.

In other words, when state changes overlap, in the conventional circuit system, the one-shot circuit 6 detects the rising edge of the signal where the state change occurred first.
．． 5 or falling detection one-shot circuit 4. The state change detection signal was sent to the calculation control device at the rising edge of the pulse signal B, but in this invention, as shown in Fig. 3, the falling detection one-shot circuits 9 and 10 are further connected to the outputs of the OR circuits 7 and 8. In order to send out a state change detection signal at the falling edge of the pulse signal of the rising edge detection one-shot circuits 6 and 5 or the falling edge detection one-shot circuits 4 and 6 of the signal whose state last changed, by adding it to the side, The calculation control device can quickly detect the state change signal, read the state signal, compare it with previous data, and detect the input that caused the state change.

In short, conventionally, we looked at the beginning of a state change, so
With this alone, delayed state changes cannot be found, so the system was designed to find them after a certain period of time, but with this invention, the state changes are checked after they have completely finished, so even at that one point in time, all state changes can be found. That's why.

Therefore, according to the present invention, since a falling detection one-shot circuit is added to the conventional circuit, a certain period of time after receiving the conventional state change detection signal [fixed time] [number of points where state changes may overlap] x pulse width t] The method that was unable to read and compare input signals has been changed to a method that allows reading and comparison with previous data when a series of state changes is completed, even when state changes occur at the same time. This has the effect that the generated signal can be detected quickly, and the process of measuring a certain period of time using software is no longer necessary, resulting in the effect of reducing the software load.

9- The main point of the invention described above is that the outputs of the conventional rising edge detection one-shot circuit and falling detection one-shot circuit are simply ORed with an OR circuit, and a falling edge detection circuit is further added to the circuit configuration that detects a state change. By adding a detection one-shot circuit, we were able to quickly change the state and reduce the software load.

[Brief explanation of the drawing]

Figure 1 is a circuit block diagram of the conventional state change detection method, and Figure 2 is a waveform diagram of the relevant parts of Figure 1. Figure 3 is a circuit block diagram of the state change detection method according to the present invention, and Figure 4 is a waveform diagram of the relevant parts of Figure 3. In the figure, 3, 5: Rising detection one-shot circuit, 4° 6 = Falling detection one-shot circuit u, 7.8: Ar circuit, 9,
10: Fall detection one-shot circuit. -10- Figure 4

Claims (1)

[Claims] A rising detection circuit and a falling detection circuit are provided for each input signal to detect state changes of multiple input signals in the calculation control device, and an OR detection circuit is provided for each of the rising and falling detection circuits and detects the OR of the respective detection outputs. and a fall detection circuit that manually inputs the output of the OR circuit and sends it to an interrupt input device of the computer control device, and causes the computer control device to read during a period when each state change detection is indispensable. A state change detection method characterized by: