JPH03282266A - Pulse input apparatus - Google Patents

Abstract

PURPOSE:To measure a time interval with high accuracy provided with function setting the generation number of times of events by respectively constituting a command execution part and a command memory in a predetermined manner. CONSTITUTION:A command execution part 101 is equipped with a change time detection means 103 detecting the change times of a plurality of pulses from an input memory 706, a time interval calculation means 104 calculating a time interval from the difference between the first event time and the second event times generated a predetermined number of times and a generation number-of- times renewing means 105 counting the generation number of times of the second events. A command memory 102 is equipped with a time interval memory means 106 and a generation number-of-times memory means 107 counting the generation number of times of the second events. In the execution part 101, the detection means 103 detects the change of an input signal 111 and, subsequently, the renewing means 105 is operated on the basis of the value of the detection confirming field of a command or the calculation means 104 calculates the time interval between the first and second events to store the same in the time interval memory means 106.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Field of Industrial Application) The present invention provides a pulse input device that measures the time interval of continuously input pulses without placing a burden on a central processing unit. More particularly, the present invention relates to a pulse input device for measuring the time interval between occurrences of a specified number of pulses.

(Prior Art) Conventionally, a pulse input device has been used as a state detection device for various devices to measure the period, pulse width, phase difference, etc. of a signal and to notify the central processing unit of the measurement results. FIG. 7 shows a block diagram of a pulse input device disclosed in Japanese Patent Application Laid-Open No. 63-295974. A pulse input device 701 shown surrounded by a dashed line is connected to a central processing unit 703 via a bus 702 . The pulse input device 701 includes an input circuit 705 that samples an input signal 704 and an input memory 706 that holds the sampled input signal 704.
, a command memory 707 connected to the bus 702 and storing commands instructed by the central processing unit 703, and an input signal 7 held in the input memory 706 based on the command.
04, a timer counter 709 that generates a reference time used by the input circuit 705, human memory 706, and command execution unit 708. Here, the central processing unit 703 periodically monitors the reception of interrupts from the pulse input device 701 or the contents stored in the command memory 707, and determines the occurrence time of a predetermined change (hereinafter referred to as an event) occurring in the input signal 704. Read out.

An input circuit 705 samples an externally applied input signal 704 for each channel at a predetermined period.

This predetermined period is determined by a sample clock generated by frequency-dividing the clock by the timer counter 709. Input memory 706 has a similar function to FIFO. That is, the input signal 704 is held for a certain period of time by sequentially holding the new input signal 704 and erasing the old input signal 704 in order. When the command execution unit 708 specifies a channel number and reads out the input signals 704 all at once, the time from the occurrence of an event to the time when the input signals 704 are read out can be determined from the holding position of the input signals 704 in the input memory 706.

The command memory 707 stores in each area a plurality of commands in which the input channel number of the event to be detected, the polarity of signal change (rising edge and falling edge), etc. are specified. Further, time information of a signal change, etc. obtained by execution by the command execution unit 708 based on this command is written at a predetermined position within the area occupied by the above command. Furthermore, there is a NOP in the free space for the reason explained later.
A command (no-action command) has been written.

A command execution unit 708 reads input signals 704 from the input memory 706 in units of channels all at once, and sequentially reads commands stored in the command memory 707 from the beginning to execute predetermined processing. and command memory 7
When the execution of the last command in command memory 707 is completed, the first command in command memory 707 is executed continuously at a certain period (
scan period). This scan period can be changed by input memory 706 by using the above NOP command.
This is adjusted to the retention period of the human input signal 704, so that no event is missed and the same event is prevented from being detected repeatedly.

With the above configuration, in the pulse input device 701, the input circuit 7
The input memory 706 holds the input signal -704 sampled for each channel in 05 for a certain period of time, and the command execution unit 708 executes the signal change specified by the command written in the command memory 707 at a scan period corresponding to this holding period. The time of occurrence of an event that matches the polarity of the event and the time interval between event occurrences are measured. This measurement result is written to a predetermined position in the above command area, and is written to the central processing unit 703.
can read out the above measurement results and know the event information of the human input signal 704.

Next, a part of an example of the internal configuration of the conventional command execution section 708 is shown in FIG.

The command execution unit 708 includes a subtracter 811 that inputs an event signal 801 from the input memory 706 and a time signal 802 from the timer counter 709, and a subtracter 812 that manually inputs an event occurrence time signal 803 output from the subtracter 811. , a V register 814 that inputs the detection signal 804 output from the subtracter 812, and a verification circuit 815 that manually inputs the event signal 801.

Based on the above configuration, first, measurement of event occurrence time will be explained.

The command execution unit 708 reads the EDGE command as the first command from the command memory 707 and executes it. That is, when the first event signal 801 that matches the polarity of the signal change specified by the first command is detected when the first command is executed, the subtracter 811 reads out the holding position of the event signal 801 after the event occurs. The event occurrence time is calculated by subtracting the time indicated by the event signal 801 from the reference time indicated by the time signal 802. This occurrence time is output to the subtracter 812 as an event occurrence time signal 803. The subtracter 812 outputs a detection signal 804 having the same value as the event occurrence time signal 803 by subtracting a 0 value from the event occurrence time indicated by the event occurrence time signal 803, and this detection signal 804 is used as the first command in the command memory 707 The first event is stored at a predetermined position in the area and in the V register 813 as the time of occurrence of the first event.

Next, measurement of time intervals between event occurrences will be described.

The command execution unit 708 consecutively executes the first command and the second command. That is, similarly to the measurement of the event occurrence time described above, the EDGE command is used as the first command, and at the end of execution of this command, the first event occurrence time is stored in the V register 813 as described above. Note that after the command scan cycle has elapsed, the first
When a command is executed, the time of occurrence of the first event is read from the command and stored in the R register 814.

Next, when a second event matching the specification of the second command is input into the input memory 706 when the second command is executed, the subtracter 811 calculates the occurrence time of the second event, and the subtracter 812 calculates the occurrence time of the second event. V from the time the event occurred
The time interval between event occurrences is calculated by subtracting the time of occurrence of the first event stored in register 813 or R register 814. This time interval is the detection signal 8
04 and is stored at a predetermined position in the second command area in the command memory 707. Note that the first command
If an event is detected and the second event is detected consecutively in a second command to be executed subsequently, the second event may have occurred before the first event, so the verification circuit 815 Verify whether the second event occurred after the first event.

In this way, the time interval between event occurrences calculated by the command execution unit 708 is stored in the second command area of the command memory 707, and the central processing unit f703 only needs to read the time interval stored in the command memory 707. .

(Problem to be solved by the invention) However, in the above-mentioned pulse input device 701, since the time difference between the first event and the first second event is measured, the measurement accuracy is insufficient for pulse measurement with a short period. There was a problem that the value decreased.

For example, assume that the resolution of the timer counter is 1 microsecond and the period of the input signal is 10 microseconds.

Considering the quantization error, the measured time interval is 10±1
This results in an error of ±10%. In order to improve accuracy, it is also possible to measure the time difference over two or more periods instead of one period as follows.

A second command (WIDTHP) is given to the pulse manpower device to generate an interrupt in continuous measurement mode.

Each time the central processing unit receives an interrupt, it counts the number of times the interrupt has occurred. Once the predetermined count is reached, the time interval is read out from the pulse input device.

However, this method had two problems. The first is an increase in the frequency of interruptions to the central processing unit and an increase in the load on the central processing unit due to counting processing. Second, since it is necessary to read the time interval after a predetermined number of interrupts occur before the next interrupt occurs, there are restrictions on the timing at which the central processing unit reads out the time intervals.

An object of the present invention is to provide a pulse input device that calculates a time interval and generates an interrupt only when a second event occurs a predetermined number of times, and that does not significantly increase costs while coexisting with conventional commands. It is.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a timer counter that counts a system clock and outputs reference time information, and a timer counter that is synchronized with the time information. An input circuit that samples input signals from multiple channels at a predetermined period; an input memory that stores the input signals sampled a predetermined number of times; a command memory that mainly stores a plurality of instructions; and a search for the instruction memory. The pulse input device includes a command execution unit that sequentially reads and executes the plurality of commands and controls the overall operation of the device, the command execution unit comprising: a change time detection unit that detects a change time of the input signal. a means for updating the number of occurrences of change in response to a change in the input signal; and a time interval calculating means for calculating a time interval from a plurality of input signal change times, and the command memory is set by a central processing unit. at least a set value for the number of occurrences of a change, a number-of-occurrence storage means for storing the number of occurrences of a change in a predetermined input signal, and a number-of-occurrence storage means for storing a time interval calculated by the above-mentioned means; It is characterized in that the means and the means for storing the number of occurrences are shared.

(Operation) By adopting the above configuration, the time interval can be calculated and an interrupt signal can be generated only when the second event occurs a predetermined number of times.

(Example) The present invention will be explained in detail below.

FIG. 1 is a block diagram of a pulse input device showing one embodiment of the present invention.

As shown in the figure, the pulse input device of this example includes the conventional input circuit 705 shown in FIG.
01 and command memory 102. here,
The command execution unit 101 uses a change time detection means 103 that detects the change time of a plurality of pulses read out continuously from the input memory 706, and a change time detection means 103 that detects the change time of a plurality of pulses read out continuously from the input memory 706, and detects the change time from the difference between the first event time and the second event time that has occurred a predetermined number of times. It has a time interval calculating means 104 for calculating a time interval, and an occurrence number updating means 105 for counting the number of occurrences of the second event. The command memory has an occurrence number storage means 106 having the same function as the conventional command memory 707, and an occurrence number storage means 107 that counts the number of occurrences of the second event.

With the above configuration, the pulse input device samples the input signal 111 and transmits it to the command execution unit 101 as in the conventional example. In the command execution unit 101, the change time detection means 103
detects a change in the input signal 111, and then updates the occurrence count updating means 10 according to the value of the detection confirmation field of the command.
5 operates, or the time interval calculation means 104
The time interval between the event and the second event is calculated and stored in the occurrence number storage means 106.

The functions of the command execution unit 101 will be explained in more detail using a block diagram showing the hardware configuration of the command execution unit shown as an embodiment in FIG.

As shown in the figure, the command execution unit of this example includes a subtracter 811 to which an event signal 201 and a time signal 202 are input, similar to the conventional command execution unit 708;
a subtracter 812 that inputs the event occurrence time signal 203 output from the subtracter 812; a V register 813 that inputs the detection signal 204 output from the subtracter 812;
An R register 814 that holds the command storage field 205, a P flag 215 that holds the state of the command being executed, a P register 214 that holds the storage field of the command that is being executed, and a verification circuit 815 that manually inputs the event signal 201. Offer. In addition, the command execution control unit 211 that inputs the verification signal 206 output from the verification circuit 815 connects the flag 212 to the control unit 211;
It consists of an R flag 213 and a P flag 215.

Here, the ■ flag 212 is set when the time of occurrence of the first event described in the conventional example is stored in the V register 813. If the command memory 707 stores the first event occurrence time, the R flag 213 is set when this stored value is read into the R register 814. Also,■
The flag 212 and the R flag 213 are reset at the end of execution of commands other than the first command. Therefore,■
The flag 212 is in the set state when the second command is executed immediately after the first event is detected, and the R flag 213 is in the set state when the second command is executed when the command memory 707 stores the first event occurrence time. . The command execution control unit 211 receives the value of each flag and the verification result from the verification circuit 815, determines and executes the processing content of the event signal 201.

Next, the commands used in this example will be explained.

The command set includes a NOP command, an EDGE command used as the first command, a WIDTH command used as the second command when measuring pulse width and phase difference, and a WIDTHP command used as the second command when measuring the period.
It consists of

The above command is defined in a fixed basic format as shown in FIG.
, an input signal channel designation field 402 , a polarity designation field 403 that designates the polarity of a signal change, and whether or not to generate an interrupt signal to the central processing unit when a predetermined event is detected. It consists of a measurement mode designation field 405 for specifying whether the measurement has been completed, a detection confirmation field 404 for indicating whether the measurement has been completed, and a storage field 406 for storing the result.

The event signal 201 is generated by the configuration of the command execution unit described above.
The measurement of the event occurrence time is performed using the EDGE command as the first command in the same manner as in the conventional example.

Next, the constant period fJ1 will be explained.

In this example, either the first command or the second command is used consecutively. If the first event is detected when the first command, EDGE command, is executed, ■Register 8
The occurrence time is stored in 13 and the V flag 212 is set. Further, when the next command memory is scanned, the above generation time is stored in the R register 814 at the start of execution of the first command, and the R flag 213 is set. Then the second
When a second event is detected during command execution, the subtracter 811 calculates the time of occurrence. Also, the subtractor 812
Depending on the states of the V flag 212 and the R flag 213, either the ■ register or the R register 814 is selected.

In period measurement, the first and second commands specify the same polarity (for example, rising edge), so an event detected when the second command is executed is also detected as an event occurring at the same time in the first command executed immediately before. and stored in the V register 813. Therefore, if the second event occurs and is detected, ■Register 813
is designed not to be selected. Therefore, when the R flag 213 is set as shown in FIG.
It is stored in the command storage field 406.

Prior to measurement, the central processing unit stores "second event occurrence count - 1" in the storage field 406 of the WIDTHP command.
and reset the detection confirmation field to "Waiting for measurement". To obtain the time interval between one conventional cycle, it is sufficient to write 0 to the storage field 406, and the conventional program can be used almost as is. The value of the detection confirmation field of the WIDTHP command changes as follows (see FIG. 3). Until the second event occurs a set number of times, O indicates "wait for measurement". After the second event occurs a set number of times, it changes to 1 indicating "measurement complete". After measuring the first command or the first event, when the same first command is executed in the next command scan, the R register 8
The first event occurrence time is stored in 14, and the R flag is set. Next, the second command WIDTHP command is "Read command from command memory"
, "Execute nj constant and store result in command memory". In the "read from command memory" step, the storage field of the WIDTHP command is stored in the P register, and the detection confirmation field is stored in the P register.
Stored in flags.

In the step "#j-determined execution and result storage", the command execution control unit 211 performs the control shown in FIG. 5. The outline is as follows. If the second event occurs when the R flag is -1, the P flag is -○, and the P register is ~0, the P register is decremented and written back to the storage field. Decrement is performed by the subtracter 812 controlling the multiplexer of the subtracter input so as to perform "P register constant number 1". When the P register is 0, which indicates that the set number of times + 1 second event has occurred, subtract the first event time stored in the R register from the latest second event time to find the time interval. Write to storage field. Furthermore, the detection confirmation field is changed to 1. FIG. 6 explains this process with a focus on the timer counter and various registers. By using this method, it is possible to measure time intervals (periods) over two or more periods, so that bronzes for measurement can be manufactured even for short-period input signals. The measurement result for the WIDTHP command is 35-1-34 microseconds. The central processing unit reads this value and divides it by the set number of times plus one to obtain a period measurement of 34/(3+1)48.5 microseconds. In conventional measurement for one period, the timer counter is 1
Since it is a microsecond measurement, only 8 or 9 microsecond measurements can be obtained, which improves accuracy. Furthermore, in the case of continuous failure, the number of event settings has no meaning, and the first event that satisfies the measurement conditions of the second command is detected. In the present invention, since both the set number of second event occurrences and the time interval measurement result use the storage field of the second command, no new field is required. The command length and format can be the same as before, so
Can coexist with conventional commands.

As described above, the present pulse input device can provide a pulse input device having the function of setting the number of event occurrences. The set value for the number of event occurrences can be specified using the storage field of the second command, and the increase in hardware compared to the conventional example is small, with only a few registers, multiplexers, etc.

[Effects of the Invention] As described above, the pulse input device provided by the present invention can measure time intervals with high precision and has the function of setting the number of event occurrences. The command set can be implemented using a simple one, and the amount of hardware required is small compared to the conventional technology. Further, the command memory can be used flexibly depending on the purpose of use.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the pulse input device according to the present invention, FIG. 2 is a block diagram showing the hardware configuration related to the command execution section, and FIG.
FIG. 4 is a state transition diagram of the THP command. FIG. 4 is an explanatory diagram of the command format of the pulse input device of the present invention. FIG. 5 is an explanatory diagram of processing by the WIDTHP command. FIG. FIG. 7 is a block diagram showing the configuration of a conventional pulse input device, and FIG.
7 is a block diagram showing the hardware configuration of the command execution unit of the pulse input device shown in FIG. 7. FIG. 01 02 03 04 05 06 07 11 05 06 09

Claims (1)

[Claims] (1) A timer counter that counts a system clock and outputs reference time information, an input circuit that samples input signals from multiple channels at a predetermined period in synchronization with the reference time information, and a predetermined number of samples. an input memory that stores the input signals of the device; a command memory that mainly stores a plurality of instructions; and a command that searches the instruction memory and sequentially reads and executes the plurality of instructions and controls the overall operation of the device. In a pulse input device having an execution section, the command execution section includes a change time detection means for detecting a change time of the input signal, a change occurrence number updating means for responding to a change in the input signal, and a change occurrence number updating means for detecting a change time of a plurality of input signals. a time interval calculation means for calculating a time interval from a time, and the command memory has a number of occurrence storage means for storing a set value of the number of occurrences of change set by a central processing unit and a number of occurrences of a change in the input signal; , and time interval storage means for storing the calculated time interval.