JP2936890B2 - Contention control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contention control device used as a communication control device for accessing a bus by a plurality of devices.

[0002]

2. Description of the Related Art FIG. 3 shows a block diagram of a conventional contention control device. FIG. 4 shows a format of information on the bus.

First, FIG. 4 will be described. As shown in FIG. 4, time slots are time-division multiplexed on the bus. Reference numeral 41 denotes a time slot request notification area. Using the time slot request notification area 41, the contention control device can notify another device of the time slot request.

Next, FIG. 3 will be described. 3 is a bus. Reference numeral 30 denotes a contention control device, which is connected to the bus 3. In FIG. 3, other contention control devices connected to the bus 3 are omitted. Reference numerals 300 and 301 denote a determination unit and a determination signal line, respectively. 310 and 320 are first and second counters, respectively. Reference numeral 311 denotes a counter signal line, which is connected to the determination unit 300. 321
Is a counter signal line, which is connected to the first counter 310. Reference numeral 350 denotes a time slot request signal transmitting unit, which is connected to the bus 3. A time slot request detection unit 330 is connected to the bus 3. 331
Is a time slot request detection signal line, which is connected to the second counter 320. Reference numeral 340 denotes an unused time slot detection unit, which is connected to the bus 3. Reference numeral 341 denotes an unused time slot detection signal line, which is connected to the first counter 310 and the second counter 320. 3
Reference numeral 51 denotes a time slot request signal line, which is connected to the time slot request signal transmitting section 350 and the first counter 310.

[0005] With respect to the competition control device comprising the above components, the relationship and operation of each component will be described below.

The unused time slot detection section 340 detects an unused time slot on the bus, and outputs a pulse from the unused time slot detection signal line 341 each time it detects it. Further, the time slot request detection section 330 detects a time slot request of another contention control device, and outputs a pulse from the time slot request detection signal line 331 every time the time slot request is detected.

The second counter 320 counts up by one each time a pulse is input from the time slot request detection signal line 331 and counts down by one each time a pulse is input from the unused time slot detection signal line 341.

[0008] When a time slot request signal is input from the time slot request signal line 351, the time slot request signal transmitting section 350 transmits a time slot request signal to the bus 3. At the same time, the count value of the second counter 320 is loaded into the first counter 310 via the counter signal line 321.

Note that the count value of the second counter 320 is the difference between the number of time slot requests and the number of unused time slots. That is, the count value of the second counter 320 is the number of time slot requests that have not been satisfied at the current time and remain.

Thereafter, the first counter 310 counts down by one every time a pulse is input from the unused time slot detection signal line 341.

The count value of the first counter 310 is determined by the determination unit 300 via a counter signal line 311.
When the count value becomes zero, a pulse from the determination signal line 301 notifies the outside that the next unused time slot that has arrived has been acquired by the device.

It is to be noted that the count value of the first counter 310 is zero when the number of time slot request signals remaining when the time slot request signal is transmitted arrives, ie, the time slot request signal Means that all the time slot requests issued before the time when the is transmitted were satisfied.

As described above, in the above-mentioned conventional competitive control device,
The number of time slot requests remaining unsatisfied at the present time is counted in the second counter 320, and when a time slot request signal is input from the time slot request signal line 351, the count of the second counter 320 is counted. The value is loaded into the first counter 310, and the count value of the first counter 310 becomes zero every time an unused time slot arrives and the time slot request is satisfied, and the count value of the first counter 310 becomes zero. After that, in order to acquire an unused time slot that has arrived first, a device that has made a time slot request earlier in time can acquire an unused time slot earlier.

[0014]

However, in the above-described conventional conflict control device, the first counter 310 keeps the second counter until the count value of the first counter 310 becomes zero.
Since the count value of the counter 320 cannot be loaded,
Unless the previous time slot request is satisfied, the next time slot request cannot be made.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an excellent contention control device capable of performing a next time slot request even during a time slot request. It is.

[0016]

According to a first aspect of the present invention, there is provided a means for counting the number of time slot requests of other contention control devices arriving after transmission of the latest time slot request. Means for buffering the number of time slot requests obtained by counting, and when making a time slot request during the time slot request, the number of time slot requests of other contention control devices arriving after transmission of the time slot request. And the number of time slot requests buffered when the count value of the first counter becomes zero and the previous time slot request is satisfied is loaded into the first counter. is there.

According to a second aspect of the present invention, there is provided a means for initializing a second counter, a means for stopping one countdown operation of the second counter, and a time slot request obtained by counting in the second counter. Means for buffering the number, buffering the count value of the second counter simultaneously with the time slot request, initializing the second counter, and performing one countdown operation until all time slot requests of the own device are satisfied. The number of timeslot requests that are stopped and buffered at the same time are loaded into the first counter.

[0018]

According to the present invention, the number of time slot requests of other contention control devices arriving after transmission of a time slot request is counted by the above configuration. The number of time slot requests of other contention control devices arriving after transmission of the time slot request is buffered, and is buffered when the count value of the first counter becomes zero and the previous time slot request is satisfied. By loading the number of requested timeslots into the first counter,
The next time slot request can be made during the time slot request.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a bus. Reference numeral 10 denotes a contention control device, which is connected to the bus 1. In FIG. 1, other contention control devices connected to the bus 1 are omitted. 100 and 101 are determination units, respectively.
This is a determination signal line. 110 and 160 are a first counter and a selector, respectively. Reference numeral 111 denotes a counter signal line, which is connected to the determination unit 100. 161 is a selector signal line, which is connected to the first counter 110. 170, 180, and 190 are a memory, a second counter, and a control unit, respectively. 171 is a data output signal line, which is connected to the selector 160. 17
Reference numeral 2 denotes an empty signal line, which is connected to the control unit 190. Reference numeral 181 denotes a counter signal line.
It is connected to the. 191 and 192 are write signal lines and read signal lines, respectively, which are connected to the memory 170. 193 is a switching signal line, and the selector 160
It is connected to the. 194 is a load signal line.
Is connected to the counter 110. 120 is a third counter (first measuring means). A counter signal line 121 is connected to the selector 160. 130
Is a time slot request detection unit, which is connected to the bus 1. Reference numeral 131 denotes a time slot request detection signal line, which is connected to the third counter 120 and the second counter 180. Reference numeral 140 denotes an unused time slot detection unit, which is connected to the bus 1. Reference numeral 141 denotes an unused time slot detection signal line, which is connected to the third counter 120 and the first counter 110. Reference numeral 150 denotes a time slot request signal transmitting unit, which is connected to the bus 1. Reference numeral 151 denotes a time slot request signal line, which includes a time slot request signal transmitting section 150 and a second counter 180.
And the control unit 190. Also, the judgment signal line 1
01 is connected to the control unit 190.

The format of information on the bus 1 is the same as that of the conventional example (FIG. 4). The first embodiment of the contention control device including the above-described components will be described below in terms of the relationship between the components and the operation in the following three operations.

1. 1. Signals input from outside and operation of internal blocks associated therewith 2. Operation when time slot request is made while time slot request is not being performed Operation when a time slot request is further performed during a time slot request First, the operation of an externally input signal and the accompanying internal block will be described.

The unused time slot detector 140 detects an unused time slot on the bus, and outputs a pulse from the unused time slot detection signal line 141 each time it detects the unused time slot. Further, the time slot request detection section 130 outputs a pulse from the time slot request detection signal line 131 every time a time slot request of another contention control device is detected.

The third counter 120 counts up by one each time a pulse is input from the time slot request detection signal line 131, and decrements by one each time a pulse is input from the unused time slot detection signal line 141.

The second counter 180 counts up by one every time a pulse is input from the time slot request detection signal line 131.

When the empty signal 172 is inactive, that is, when the memory 170 stores data, the selector 160 outputs the data output of the memory 170 from the selector signal line 161. When the empty signal 172 is active, that is, when the memory 170 does not store data, the count value of the third counter 120 input from the counter signal line 121 is output from the selector signal line 161.

The control unit 190 counts the number of time slots for which the acquisition request is not satisfied in its own device from the time slot request signal from the time slot request signal line 151 and the pulse from the determination signal line 101.

2. Next, an operation when a time slot request is made in a state where a time slot request is not being performed will be described.

When a time slot request signal is input to the time slot request signal line 151, the time slot request signal sending section 150 sends a time slot request signal to another contention control device. At the same time, the counter signal line 12
1. The count value of the third counter 120 is loaded into the first counter 110 through the selector 160 and the selector signal line 161. At the same time, the second counter 1
Reset 80. Note that the count value of the third counter 120 is the difference between the number of time slot requests and the number of unused time slots, that is, the number of time slot requests remaining unsatisfied at the present time.

Thereafter, the first counter 110 is decremented by one each time a pulse is input from the unused time slot detection signal line 141.

The count value of the first counter 110 is determined by the determination unit 100 via the counter signal line 111.
When the count value becomes zero, a pulse from the determination signal line 101 notifies the outside that the next unused time slot that has arrived has been acquired by the device. It should be noted that the count value of the first counter 110 is zero when the unused time slots of the number of time slot requests remaining at the time of transmitting the time slot request signal have arrived, that is, the time slot request signal has been transmitted. It means that all the remaining time slot requests at that time have been satisfied.

3. Lastly, an operation when a time slot request is further performed during a time slot request will be described.

Since a time slot request is being made, the count value of the first counter 110 has not become zero, and it is in operation.

When a time slot request signal is input to the time slot request signal line 151, the time slot request signal sending section 150 sends a time slot request signal to another contention control device. Further, since the time slot request signal is received by the control unit 190 in a state where the number of time slots for which the acquisition request is not satisfied in the own device is not zero,
The control unit 190 outputs a pulse to the write signal line 191 to store the count value of the second counter 180 in the memory 170.
Write to. At the same time, the second counter 180 is reset.

Therefore, the count value of the second counter 180 is the total number of time slot requests newly notified since the last time slot request was made. When the count value of the first counter 110 becomes zero and a pulse is output from the determination signal line 101 in a state where the empty signal line 172 is inactive, the control unit 190 switches the selector 160 through the switching signal line 193. By outputting pulses to the read signal line 192 and the load signal line 194, the first counter 110 is loaded with the number of time slots buffered in the memory 170.

Thereafter, the above operation is repeated until the memory 170 becomes empty and the empty signal line 172 becomes active.

As described above, according to the first embodiment,
The second counter 180 counts the time slot requests after the previous time slot request of the own device, and if a further time slot request is made during the time slot request, the count value of the second counter 180 is buffered. In order to set the count value that has been buffered since the previous time slot request was satisfied as the initial value of the new first counter 110, the next time slot request is issued even though the time slot request is being performed. It has the advantage that it can be performed.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 2, reference numeral 2 denotes a bus. Reference numeral 20 denotes a contention control device, which is connected to the bus 2. In FIG. 2, other contention control devices connected to the bus 2 are omitted. Reference numerals 200 and 201 denote a determination unit and a determination signal line, respectively. 210 and 270 are a first counter and a memory, respectively. Reference numeral 211 denotes a counter signal line, which is connected to the determination unit 200. 271
Is a data output signal line of the memory 270, which is connected to the first counter 210. 230 and 280 are a gate circuit and a control unit, respectively. Reference numeral 272 denotes an empty signal line, which is connected to the control unit 280. 220 is a second counter. 221 is a counter signal line,
It is connected to the memory 270. Reference numerals 281 and 282 denote a write signal line and a read signal line, respectively.
70. 283 is a load signal line,
It is connected to a first counter 210. Reference numeral 284 denotes a gate control signal line, which is connected to the gate circuit 230. Reference numeral 240 denotes a time slot request detection unit,
It is connected to the. Reference numeral 241 denotes a time slot request detection signal line, which is connected to the second counter 220.
Reference numeral 250 denotes an unused time slot detection unit, which is connected to the bus 2. Reference numeral 251 denotes an unused time slot detection signal line, which is connected to the gate circuit 230 and the counter 210. Reference numeral 260 denotes a time slot request signal transmitting unit. Reference numeral 261 denotes a time slot request signal line, which is connected to the time slot request signal transmitting section 260, the counter 220, and the control section 280. Also, the judgment signal line 201
Are connected to the control unit 280. The format of the information on the bus 1 is the same as the conventional example (FIG. 4).

In the second embodiment of the contention control device having the above-described components, the relationship and operation of each component will be described separately for the following three operations.

1. 1. Signals input from outside and operation of internal blocks associated therewith 2. Operation when time slot request is made while time slot request is not being performed Operation when a time slot request is further performed during a time slot request First, the operation of an externally input signal and the accompanying internal block will be described.

The unused time slot detector 250 detects an unused time slot on the bus, and outputs a pulse from the unused time slot detection signal line 251 each time it detects it. Further, the time slot request detection section 240 detects a time slot request from another contention control device, and outputs a pulse from the time slot request detection signal line 241 each time the time slot request is detected.

When the gate control signal line 284 is active, the counter 220 counts up by one every time a pulse is input from the time slot request detection signal line 241.
Each time a pulse is input from the unused time slot detection signal line 251, the countdown is performed by one.

If the gate control signal line 284 is inactive, the second counter 220 counts up only by one every time a pulse is input from the time slot request detection signal line 241.

The control unit 280 counts the number of time slots for which the acquisition request is not satisfied in its own device, based on the time slot request signal from the time slot request signal line 261 and the pulse from the determination signal line 201.

2. Next, an operation when a time slot request is made in a state where a time slot request is not being performed will be described.

When a time slot request signal is input to the time slot request signal line 261, the time slot request signal sending section 260 sends a time slot request signal to another contention control device. At the same time, the counter signal line 22
1, the count value of the second counter 220 through the memory 270 and the data output signal line 271,
Loaded to 0. At the same time, the second counter 220
Reset.

Since the control unit 280 treats the request as an unsatisfied time slot request, the gate control signal line 284 becomes inactive, and the countdown of the second counter 220 by the unused time slot detection signal is not performed.

Thereafter, the first counter 210 is decremented by one every time a pulse is input from the unused time slot detection signal line.

The count value of the first counter 210 is determined by the determination unit 200 via the counter signal line 211.
When the count value becomes zero, a pulse from the determination signal line 201 notifies the outside that the next unused time slot that has arrived has been acquired by the device. At this time, if there is no next time slot request of the own device, the control unit 280 detects that there is no unsatisfied time slot request.
84 becomes active, and the countdown of the second counter 220 by the unused time slot detection signal is restarted.

It should be noted that the count value of the first counter 210 is zero when the number of time slot requests remaining when the time slot request signal is transmitted arrives, ie, the time slot request signal Means that all the remaining time slot requests at the time of sending are transmitted.

3. Lastly, an operation when a time slot request is further performed during a time slot request will be described.

Since a time slot request is being made, the count value of the first counter 210 is not zero, and the first counter 210 is operating. Further, the gate control signal line 284 is inactive.

When a time slot request signal is input to the time slot request signal line 261, the time slot request signal sending section 260 sends a time slot request signal to another contention control device. Further, since the time slot request signal is received by the control unit 280 in a state where the number of time slots for which the acquisition request is not satisfied in the own device is not zero,
The control unit 280 outputs a pulse to the write signal line 281 to write the count value of the second counter 220 to the memory. At the same time, the second counter 220 is reset.

When the count value of the first counter 210 becomes zero and a pulse is output from the determination signal line 201 in a state where the empty signal line 272 is inactive, the control unit 280 causes the read signal line 282 and the load signal By outputting a pulse to the signal line 283, the first counter 210 is loaded with the number of time slots buffered in the memory 270.

Thereafter, the above operation is repeated until the memory 270 becomes empty and the empty signal line 272 becomes active.

As described above, according to the second embodiment,
The second counter 220 counts time slot requests since the previous time slot request of the own device. If a further time slot request is made during the time slot request, the count value of the second counter 220 is buffered. After the time slot request is satisfied, the buffered count value is used as the new initial value of the first counter 210 after the previous time slot request is satisfied. Can be performed.

[0057]

As is apparent from the above description of the embodiment, the present invention counts the number of time slot requests of other contention control devices arriving after transmission of a time slot request,
When a time slot request is further performed during a time slot request, the number of time slot requests of other contention control devices arriving after the transmission of the time slot request is buffered, and the counter becomes zero to satisfy the previous time slot request. The number of time slot requests buffered at the time of the request is loaded into the counter, which has the effect that the next time slot request can be made during the time slot request.

[Brief description of the drawings]

FIG. 1 is a block diagram of a contention control device according to a first embodiment of the present invention;

FIG. 2 is a block diagram of a contention control device according to the second embodiment;

FIG. 3 is a block diagram of a conventional conflict control device.

FIG. 4 is a diagram for explaining an information format on a bus.

[Explanation of symbols]

1 Bus 100 Judgment Unit (Time Slot Acquisition Judgment Means) 120 Third Counter (First Measurement Means) 150 Time Slot Request Signal Sending Unit (Means for Requesting Bus to Acquire Time Slot) 170 Memory (Holding Means) ) 180 second counter (second measuring means)

Claims (2)

(57) [Claims] 1. A means for issuing a time slot acquisition request to a bus, a first measuring means for measuring the number of time slots for which the acquisition request is not satisfied, and a time acquired by the own apparatus and another apparatus. A second measuring means for measuring the number of slots, and the number of unused time slots which have been inputted as input values of the number of time slots measured by the first measuring means and which have passed on the bus coincided with the input value. A time slot acquisition determining means for making a determination to acquire an unused time slot in the case where the own device has made an unsatisfied time slot acquisition request; Holding means for holding the number of time slots measured by the second measuring means, and determining whether to acquire an unused time slot. When the, when the holding means is not empty, contention control apparatus according to claim a number of time slots that held by the holding means to a new input value to the time slot acquisition determination means. Means for making a time slot acquisition request to the bus, means for counting the number of time slots requested to be acquired by the own device and another device, and said measurement for each time slot acquisition request of the own device. Means for holding the number of time slots measured by the means for performing, and when the number of unused time slots passed on the bus after inputting the number of time slots held by the holding means as an input value matches the input value. Having time slot acquisition determining means for making a determination to acquire an unused time slot, wherein the number of time slots held by the holding means is not present, and the unused time slot in the time slot acquisition determining means is provided. Each time an unused time slot passes through the bus in a state where the determination of acquiring A contention control device characterized in that the stage subtracts the number of time slots being measured.