JP2003114870A - Bus intervening method and bus intervening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem with bus intervention that, though it is avoided by counting the number of times of the bus use right request by a bus master that the acquisition of a bus use right is delayed for a time more than necessary when a bus is intervened, a bus use time required for the processing of the bus master cannot be assured and the processing of the bus master may fail. SOLUTION: Each bus master measures a bus use time using a common bus by each bus use time measuring part, and compares the measured bus use time with a bus use permitted time capable of using the common bus within a prescribed time set for each bus master. A bus use right for the common bus is not given to the bus master having the bus use time exceeding the bus use permitted time. Thus the bus use time required for the processing of the other bus masters can be assured, and the processing of each bus master can be performed without fail.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus arbitration method and a bus arbitration device, and more particularly, to an improved bus arbitration device so that processing of each bus master is not broken.

[0002]

2. Description of the Related Art In a conventional bus arbitration method and bus arbitration device, in order to prevent the processing of each bus master from failing, the priority order for acquiring the bus use right is set in accordance with the priority of the processing of each bus master. In general, a method of defining in advance and giving a bus use right to each bus master according to the defined priority order is common.

However, if the priority order for acquiring the bus use right is fixed, a bus master with a lower priority order may not be able to acquire the bus use right forever, so that the processing of the bus master fails. There is.

In addition, there is a method of equalizing the opportunities for acquiring the bus use right, such as lowering the priority of the bus master to the lowest when a bus master acquires the bus use right.
In reality, since bus masters with different bus usage time and waiting time limits when the bus usage right is obtained are often connected, it is important to equalize the bus usage right acquisition process. It cannot be generally said that it is efficient because it does not fail. Therefore, arbitration according to the circumstances of each connected bus master is efficient.

As a means for preventing the processing of the bus master from failing, the number of bus usage right acquisition requests from each bus master is counted, and the number of bus usage right acquisition requests of a specific bus master is For example, if the specified bus master becomes longer than the preset value in consideration of the waiting time without starting the processing after issuing the bus usage right acquisition request, the specified bus master will be A method of determining that the bus has not been acquired and suppressing the request for acquisition of the bus usage right to the other bus masters other than the specific bus master to allow the specific bus master to acquire the bus usage right is there. As a result, it is possible to prevent the acquisition of the bus use right of the specific bus master from being delayed more than necessary.

[0006]

However, in the above method, the bus usage required for the processing of each bus master is simply avoided by avoiding waiting for the acquisition of the bus usage right of a specific bus master more than necessary. The time cannot be guaranteed, and there is still the possibility that the processing of the bus master will fail. The present invention has been made in view of the above problems of the conventional ones, and an object of the present invention is to obtain a bus arbitration method and a bus arbitration device capable of arbitrating a bus right without causing a failure of processing of a bus master. Has an aim.

[0007]

In order to solve the above problems, a bus arbitration method according to a first aspect of the present invention provides a bus use permission time in which a plurality of bus masters can use a common bus within a predetermined time. Is set for each bus master in advance, each of the bus masters measures the bus usage time using the common bus, and when the bus usage time exceeds the bus usage permission time for one of the bus masters, This is characterized in that the bus master is not given the bus use right of the common bus.

Further, in the bus arbitration method according to claim 2 of the present invention, a plurality of bus masters sets a bus use permission time in advance for each bus master to use a common bus within a predetermined time. The bus master measures the bus usage time using the common bus, and if the bus usage time exceeds the bus usage permission time for one of the bus masters, the bus usage right is granted to each of the multiple bus masters. It is characterized by assigning priorities for acquisition.

A bus arbitration method according to claim 3 of the present invention is the bus arbitration method according to claim 1 or 2, wherein
The bus use permission time of each of the plurality of bus masters is adjusted according to the measured bus use time of each of the plurality of bus masters.

According to a fourth aspect of the present invention, there is provided a bus arbitration device which measures a bus use time when each of the plurality of bus masters uses a common bus, and a measuring means for measuring the bus use time of each of the plurality of bus masters. And a bus use right decision means for observing the bus use time and deciding whether or not to give the bus use right of the common bus to each bus master.

A bus arbitration apparatus according to a fifth aspect of the present invention is the bus arbitration apparatus according to the fourth aspect, wherein the bus usage right decision means is a bus usage time measured by the measurement means of each bus master, The bus use permission time set in advance for each bus master is compared with each other, and the bus use right of the common bus is not given to the bus master whose bus use time exceeds the bus use permission time.

A bus arbitration device according to a sixth aspect of the present invention is the bus arbitration device according to the fourth aspect, wherein the bus usage right decision means is a bus usage time measured by the measurement means of each bus master, When the bus use permission time set in advance for each bus master is compared, and when the bus use time exceeds the bus permission time, the priority order for acquiring the bus use right is assigned to each bus master.

A bus arbitration device according to claim 7 of the present invention is the bus arbitration device according to claim 4 or 5, wherein:
A bus use permission time adjusting means for adjusting the bus use permission time according to the bus use time of each bus master measured by the measuring means is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a bus arbitration device according to a first embodiment of the present invention, and FIG. 2 is a bus arbitration according to the first embodiment of the present invention. It is a flowchart which shows the flow of a process of the bus arbitration method in an apparatus. The configuration of the bus arbitration device according to the first embodiment of the present invention will be described with reference to FIG.

The bus masters 10, 11, 12 are the common bus 1
Connected to 3. The bus arbitration unit 14 is provided with the bus arbitration control unit 140 and the bus masters 10, 11 and 12, respectively.
11, 1412 and bus usage time measuring units 1420, 1
It is composed of 421 and 1422. In the bus arbitration unit 14, the bus arbitration control unit 140 controls the bus masters 10, 1
Requests for acquisition of the right to use the bus 13 from the bus Nos. 1 and 12 are set by the bus use permission time setting units 1410, 1411 and 1412 and the bus use time measuring units 1420, 1421 and 1422.
The bus mastership request is arbitrated while monitoring the measurement result of the bus master, and the bus 13 is sent to any of the bus masters 10, 11, and 12.
Give bus usage rights. Bus allowed time setting unit 141
In 0, the time that the bus master 10 can use the bus 13 within a predetermined time is set. Similarly, the bus master 11 is set in the bus use permission time setting unit 1411, and the bus master 12 is set in the bus use permission time setting unit 1412 so that the bus 13 can be used within a predetermined time. The bus usage time measuring unit 1420 measures the time when the bus master 10 used the bus 13 within a predetermined time. Similarly, the bus usage time measuring unit 1421 measures the time when the bus master 11 and the bus usage time measuring unit 1412 use the bus 13 within a predetermined time.

Next, the processing flow of the bus arbitration method in the bus arbitration device according to the first embodiment of the present invention will be described with reference to FIG. In step S201 of FIG. 2, when the bus master 10 wants to use the bus 13, it issues a bus use right acquisition request 101 to the bus arbitration device 14. Similarly, when the bus masters 11 and 12 want to use the bus 13, bus usage right acquisition requests 111 and 121 are issued to the bus arbitration device 14.

In step S202 of FIG. 2, the bus arbitration control unit 140 selects a bus master candidate to which the bus use right is given. Here, in case the bus mastership acquisition requests for the bus 13 are issued simultaneously from the bus masters 10, 11, and 12, it is assumed that each bus master is given a fixed priority for bus mastership acquisition. If the bus usage right acquisition request is issued at the same time, the bus arbitration control unit 140 uses the bus master with the highest priority for bus usage right acquisition as the candidate, and if the bus usage right acquisition request is not issued at the same time. A bus master that has requested acquisition of the bus use right is selected as the candidate.

In step S203 of FIG. 2, the set value of the bus use permission time setting unit corresponding to the bus master selected in step S202 of FIG. 2 is compared with the measurement value measured by the bus use time measuring unit. For example, if the selection result of step S202 in FIG. 2 is the bus master 10, the bus use permission time setting unit 14 that sets the time during which the bus master 10 can use the bus within a predetermined time is set.
The set value of 10 is compared with the value measured by the bus usage time measuring unit 1420.

As a result of the comparison in step S203 of FIG. 2, when the measured value is smaller than the set value, the bus arbitration control unit 140 uses the bus of the bus 13 for the bus master selected in step S204 of FIG. Give the right. At this time, the bus use time measuring unit corresponding to the bus master to which the bus use right is given starts measuring the time when the bus master uses the bus 13 in step S205 of FIG.

On the other hand, as a result of the comparison in step S203 of FIG. 2, when the measured value is greater than or equal to the set value, the bus arbitration control unit 140 selects the candidate bus master to give the bus use right in step S202 of FIG. Select again. As a result of the selection in step S202 of FIG. 2, if there is no candidate to grant the bus use right, the bus arbitration control unit 140 waits for the bus use right acquisition request in step S206 of FIG.

In the bus arbitration unit 14, step S in FIG.
While measuring the bus usage time of 205, in step S207 of FIG. 2, the bus arbitration control unit 140 sets the value of the bus usage permission time setting unit for the bus master that is using the bus 13 and the value in step S205 of FIG. Compare with the measured value.

When the measured value is greater than or equal to the set value as a result of the comparison in step S207 of FIG. 2, the bus arbitration control unit 140 determines in step S208 of FIG. 2 the bus master currently using the bus 13. The bus usage right is stripped, and the process enters a waiting state for the bus usage right acquisition request in step S206 of FIG.

On the other hand, as a result of the comparison in step S207 of FIG. 2, when the measured value is smaller than the set value, the bus arbitration control unit 140 executes step S209 of FIG.
In step S204, it is checked whether the bus master that has acquired the bus use right is using the bus 13.

As a result of the check in step S209 in FIG. 2, when the bus master is using the bus 13, the measurement of the bus use time in step S205 in FIG. 2 is continued. On the other hand, when the bus master has finished using the bus 13, the bus use time measuring unit, which was measuring the bus use time in step S205 of FIG. 2, suspends the measurement,
The bus arbitration control unit 140 enters a waiting state for the bus usage right acquisition request in step S206 of FIG.

The bus arbitration method according to this embodiment will be specifically described. In FIG. 1, the bus master 10
Is a G.G. It is assumed that the audio / video communication system is such that the audio encoding unit is 723.1, the bus master 11 is an image encoding unit whose image encoding method is MPEG-4, and the bus master 12 is a CPU. In the system, the predetermined time is 10 ms.

The time required for each bus master to transfer data is set in the bus use permission time setting section. If the voice coding rate of the bus master 10 is 6.3 kbps, the coded voice coded data can be transferred if 1.2 ms can be used within the 10 ms. 723.1 needs to be available for 3.6 ms within the 10 ms in order to output encoded data once in 30 ms. The time required for the bus master 11 to use the bus may be 5 ms within 10 ms when the image coding rate is 32 kbps. The remaining 1.4 ms of the 10 ms is given to the bus master 12.

The bus masters 10 of the audio encoding unit are assigned in descending order of priority when the bus mastership acquisition requests for the common bus are simultaneously issued from the respective bus masters.
It is assumed that they are the bus master 11 and the bus master 12 of the image encoding unit.

If the bus master 12 issues a bus use right acquisition request immediately after the system starts operating (step S201 in FIG. 2), the bus arbitration control section 140 selects a bus master candidate to which the bus use right is given. Then, the bus master 12 is selected (step S202 in FIG. 2).
Next, the bus arbitration control unit 140 compares the set value of 1.4 ms in the bus usage permission time setting unit corresponding to the bus master 12 with the measurement value measured by the bus usage time measurement unit (step S203 in FIG. 2). In this case, the bus master 12 is the bus 1
Since 3 is not used yet, the measured value of the bus usage time measuring unit is 0 ms. Therefore, the result of the comparison is that the set value of the bus use permission time setting unit is larger, so that the bus arbitration control unit 140 sends the bus master 12 to the bus 1
The bus use right of No. 3 is given (step S204 of FIG. 2).
At the same time, the bus use permission time setting unit 1422 corresponding to the bus master 12 starts measuring the bus use time and measures the time while the bus master 12 is using the bus 13 (step S205 in FIG. 2).

At this time, the bus master 12 sets the bus 13.
If 0 ms is used, the bus usage time measuring unit 1422
Is 1.0 ms, and when compared with the set value of the bus use permission time setting unit 1421 (step S207 in FIG. 2), the set value of 1.4 ms is larger than the measured value of 1.0 ms. In addition, the bus master 12 is the bus 13
Is not used (step S20 of FIG. 2).
9), the bus arbitration control unit 140 waits for a bus usage right acquisition request (step S206 in FIG. 2).

The bus usage time measuring unit 1422 measures the time when the bus master 12 is using the bus 13 (step S205 in FIG. 2). When trying to use 13, the bus arbitration control unit 140 deprives the bus master 12 of the bus use right because the measured value becomes equal to or more than the set value (step S207 in FIG. 2), and the bus master 12 stops the bus 13 Is stopped (step S20 in FIG. 2).
8), the bus arbitration control unit 140 waits for a bus usage right acquisition request (step S206 in FIG. 2).

When the bus arbitration control section 140 waits for the bus usage right acquisition request, it is assumed that the bus usage right acquisition request is issued only from the bus master 12 again (step S201 in FIG. 2). The unit 140 will select the bus master 12 as a candidate for the bus master to which the bus use right is given (step S202 in FIG. 2). However, if the set value is compared with the measured value (step S203 in FIG. 2), the bus arbitration control unit 140 does not give the bus right to the bus master 12 because the measured value is equal to or larger than the set value. Waiting for the right to use request (Fig. 2
Step S206).

By the above processing, when a certain bus master tries to use the common bus for more than the bus use permission time of the common bus, the bus master is not given the common bus use right, so that the other bus masters other than the bus master do not have the common bus use right. The bus use time required for processing can be secured, and the processing of each bus master can be executed without failure.

As described above, in the bus arbitration method according to the first embodiment, a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In a bus arbitration method for arbitrating conflicts of rights, each of the plurality of bus masters is
A bus use permission time in which the common bus can be used within a predetermined time is set in advance for each of the bus masters, and each of the plurality of bus masters measures the bus use time of using the common bus. When the bus use time exceeds the bus use permission time for a certain bus master, the bus use right of the common bus is not given to the bus master, so that it is necessary for the processing of each bus master. There is an effect that the bus usage time can be secured and the bus usage right contention can be arbitrated without breaking the processing of each bus master.

The image coding method is not limited to the above method, but may be MPEG1, MPEG2, MPEG-4,
ITU-TH. Other methods such as H.261 and Wavelet conversion may be used. Also, the audio encoding method is not limited to the above method, but may be MPEG1, MPEG2, M
PEG-4, G.I. Other methods such as 729 may be used. Further, the image coding rate and the audio coding rate are not limited to the numbers described in this embodiment.

The set value set in the bus use permission time setting section is not limited to the time required for each bus master to transfer data, and may be another set value. Further, the set value set in the bus use permission time setting unit is not limited to the number described in this embodiment.

Further, the priorities to be given when the bus mastership acquisition requests for the common bus are simultaneously issued from the respective bus masters are not limited to those described in this embodiment. In addition, the method of measuring the bus usage time by the bus usage time measuring unit is not the method of actually measuring the time,
Another method such as calculation using the data transfer rate of the common bus and the data transfer amount from each bus master may be used.

The method of selecting a bus master candidate that gives the bus use right when the bus mastership acquisition requests for the common bus are simultaneously issued from the bus masters to the bus arbitration device is not limited to the above method. Prioritize the bus mastership to each bus master, and if the bus master with the highest priority among the bus masters that issued the bus mastership acquisition request acquires the bus mastership and that bus master uses the bus, the bus mastership has priority. Alternatively, another method such as a method using a round robin method in which the bus sequentially moves to another bus master may be used. Also, the number of common buses may be one instead of one.

(Second Embodiment) From this, the second embodiment of the present invention will be described.
The embodiment will be described. FIG. 3 shows the second aspect of the present invention.
FIG. 4 is a block diagram showing a configuration of a bus arbitration device according to the embodiment of the present invention, and FIG. 4 is a flow chart of processing of a bus arbitration method according to the second embodiment of the present invention.

The configuration of FIG. 3 in the second embodiment is basically the same as that of FIG. 1 shown in the first embodiment, but a bus use right acquisition priority assigning unit 340 and a bus use right acquisition request confirming unit are provided. 1 in that it has 341.

The processing flow of the basic bus arbitration method according to the second embodiment is the same as the processing flow of the bus arbitration method according to the first embodiment, but a candidate bus master to grant the bus use right. To assign each bus master a new priority for bus usage right acquisition, confirmation of whether the bus usage right acquisition priority has been changed, and whether or not a bus usage right acquisition request has been issued. The processing to do is added. In FIG. 4, the processing elements given the same reference numerals as those in FIG. 2 indicate the same processing elements as those in FIG.

First, regarding the configuration of the bus arbitration device according to the second embodiment of the present invention, only the blocks newly added to the bus arbitration device according to the first embodiment of the present invention will be described with reference to FIG. However, the description of the same block will be omitted.

The newly added blocks are the bus use right acquisition priority assigning unit 340 and the bus use right acquisition request confirming unit 341 shown in FIG. The bus use right acquisition priority assigning unit 340 monitors the bus use permission time setting unit and the bus use time measuring unit for the priority order for the bus arbitration control unit 140 to select a bus master candidate to which the bus use right is given. Perform new allocation processing. The bus use right acquisition request confirmation unit 341 confirms whether or not the bus mastership acquisition request is issued from the bus master to the bus arbitration unit 14.

Subsequently, the processing flow of the bus arbitration method in the bus arbitration device according to the second embodiment of the present invention is newly added to the bus arbitration method according to the first embodiment of the present invention. Figure 4 only for processing and different processing
Will be described and the description of the same processing will be omitted.

In step S201 of FIG. 4, each bus master issues a bus use right acquisition request to the bus arbitration device 14 when it wants to use the bus 13. Step S20 of FIG.
In 2, the bus arbitration control unit 140 selects a bus master candidate to which the bus use right is given. Bus master 1
It is assumed that each bus master is given a fixed priority for bus usage right acquisition in case a bus usage right acquisition request for the bus 13 is simultaneously issued from 0, 11, and 12. If the bus usage right acquisition request is issued at the same time, the bus arbitration control unit 140 uses the bus master with the highest priority for bus usage right acquisition as the candidate, and if the bus usage right acquisition request is not issued at the same time. A bus master that has requested acquisition of the bus use right is selected as the candidate.

In step S401 of FIG. 4, the bus use right acquisition priority assigning unit 340 executes step S401 of FIG.
At 402, it is confirmed whether or not the bus use right acquisition priority order has been changed. As a result of the confirmation in step S401 in FIG.
When the priority order of bus use rights has not been changed, Fig. 4
In step S203 of FIG.
The set value of the bus use permission time setting unit corresponding to the bus master selected in step 3 is compared with the measurement value measured by the bus use time measuring unit. For example, if the selection result of step S202 in FIG. 4 is the bus master 10, the bus master 1
When 0 is set, the time allowed to use the bus within a predetermined time is set, and the set value of the bus use permission time setting unit 1410 is compared with the value measured by the bus use time measuring unit 1420.

On the other hand, as a result of the confirmation in step S401 of FIG. 4, when the bus use right acquisition priority is changed, step S204 of FIG. 4 is executed. Step S2 in FIG.
As a result of the comparison of 07, when the measured value is smaller than the set value, the bus arbitration control unit 140 causes the bus arbitration control unit 140 to perform step S20 in FIG.
The bus mastership of bus 13 is given to the bus master selected in 4. At this time, the bus use time measuring unit corresponding to the bus master to which the bus use right has been given, performs the step S in FIG.
At 205, the bus master starts measuring the time when the bus 13 is used.

On the other hand, as a result of the comparison in step S207 of FIG. 4, when the measured value is greater than or equal to the set value, the bus right acquisition priority assigning unit 340 causes the bus master selected in step S402 of FIG. The bus arbitration control unit 140 again selects the bus master candidate to which the bus use right is given in step S202 of FIG.

As a result of the selection in step S202 of FIG. 4, if there is no candidate to grant the bus use right, step S2 of FIG.
In 06, the bus arbitration control unit 140 enters a waiting state for a bus usage right acquisition request. In the bus arbitration unit 14, while measuring the bus use time in step S205 of FIG.
In step S207 of FIG. 4, the bus arbitration control unit 14
0 is the set value of the bus use permission time setting unit for the bus master currently using the bus 13 and step S2 of FIG.
The measured value measured in 05 is compared.

As a result of the comparison in step S207 of FIG. 4, when the measured value is greater than or equal to the set value, the bus use right acquisition request confirmation unit 34 in the bus arbitration control unit 140 is confirmed.
In step S403 of FIG. 4, the first node confirms whether or not a bus use right acquisition request has been issued by another bus master.

As a result of the confirmation in step S403 of FIG. 4, when the bus use right acquisition request is not issued, the processing of step S209 of FIG. 4 is performed.

On the other hand, as a result of the confirmation in step S403 in FIG. 4, when the bus use right acquisition request is issued, the bus arbitration control unit 140 determines in step S208 in FIG. 4 that the bus master currently using the bus 13 is in use. The bus use right is deprived and the process of step S202 of FIG. 4 is performed.

As a result of the comparison in step S207 of FIG. 4, when the measured value is smaller than the set value, the bus arbitration control unit 140 checks in step S209 of FIG. 4 whether the bus master is using the bus 13. To do.

As a result of the check in step S209 in FIG. 4, when the bus master is using the bus 13, the measurement of the bus use time in step S205 in FIG. 4 is continued. On the other hand, when the bus master has finished using the bus 13, the bus use time measuring unit, which was measuring the bus use time in step S205 of FIG. 4, suspends the measurement,
The bus arbitration control unit 140 enters a waiting state for the bus use right acquisition request in step S206 of FIG.

The bus arbitration method according to the second embodiment will be specifically described. In FIG. 3, the bus master 1
0 is G. It is assumed that the audio / video communication system is such that the audio encoding unit is 723.1, the bus master 11 is an image encoding unit whose image encoding method is MPEG-4, and the bus master 12 is a CPU. In the system, the predetermined time is 10 ms.

The time required for each bus master to transfer data is set in the bus use permission time setting section. If the voice coding rate of the bus master 10 is 6.3 kbps, the coded voice coded data can be transferred if 1.2 ms can be used within the 10 ms. 723.1 needs to be available for 3.6 ms within the 10 ms in order to output encoded data once in 30 ms. The time required for the bus master 11 to use the bus may be 5 ms within 10 ms when the image coding rate is 32 kbps. The remaining 1.4 ms of the 10 ms is given to the bus master 12.

In addition, when the bus mastership acquisition requests for the common bus are simultaneously issued from the respective bus masters, the bus master 10 of the audio encoding unit, the bus master 11 of the image encoding unit, and the bus master are assigned in descending order of priority. It is assumed to be 12.

In this embodiment, when the bus master 11 transfers the voice coded data during the predetermined time 1 as shown in FIG. 5, the next voice coded data is transferred at the predetermined time 4. In this way, during the predetermined times 2 and 3, the bus use permission time of 3.6 ms given to the bus master 11 can be used by other bus masters.

If the bus master 10 issues a bus use right acquisition request at a predetermined time 2 in FIG. 5, the bus arbitration control unit 140 selects the bus master 11 as a candidate for the bus master to which the bus use right is given (see FIG. 4). Step S20
2), the priority is the bus use right acquisition priority assigning unit 34
It is confirmed whether it has been changed by 0 (step S401 in FIG. 4). In this case, since the priority order has not been changed, the bus arbitration control unit 140 grants the bus mastership right to the bus master 11 (step S204 in FIG. 4), and the bus usage permission time setting unit 1421 corresponding to the bus master 12 uses the bus mastership time. Time measurement starts, and the bus master 11
While using, the time is measured (step S205 in FIG. 4).

While the bus use permission time setting unit 1421 performs the measurement, the bus master 11 sets the set value 5.0.
When it is attempted to use the bus 13 for more than ms, the measured value becomes the set value or more (step S in FIG. 4).
207), the bus arbitration control unit 140 deprives the bus master 11 of the bus use right, and stops the bus master 11 from using the bus 13 (step S208 in FIG. 4), and the bus arbitration control unit 140 waits for the bus use right acquisition request. Enter (step S206 of FIG. 4).

Next, when the bus arbitration control unit 140 is waiting for the bus use right acquisition request, the bus master 11
Assume that the bus usage right acquisition request is issued only by
Step S201) and the bus arbitration control unit 140 selects the bus master 11 as a bus master candidate to which the bus usage right is given (step S202 in FIG. 4).
As a result of comparing the set value with the measured value (step S203 in FIG. 4), the bus arbitration control unit 140 has the lowest priority for bus master 11 to acquire the bus use right because the measured value is equal to or larger than the set value. The order is changed (step S402 in FIG. 4).

After the above change, the bus arbitration control unit 140 is again used.
Selects a bus master candidate to which the bus usage right is given (step S202 in FIG. 4). However, since the bus usage right acquisition request is issued only from the bus master 11, the bus arbitration control unit 140 selects the bus master 11 as the candidate. And After the selection, it is confirmed whether or not the priority order for obtaining the bus use right is changed (step S401 in FIG. 4), and since it has been changed, the bus master 11 is granted the bus use right.
After the permission, while the bus master 11 is using the bus 13, the bus use permission time set value is compared with the bus use time measured value (step S207 in FIG. 4), but the set value is smaller than the measured value. Therefore, the bus usage right acquisition request confirmation unit 341 continues to check whether or not the bus usage right acquisition request is issued (step S4 in FIG. 4).
03). As a result of the confirmation, if a bus use right acquisition request has been issued, the bus arbitration control unit 140 causes the bus master 11 to stop using the bus (step S20 in FIG. 4).
8) Then, a bus master candidate to which the bus use right is given is selected (step S202 in FIG. 4).

According to the above-mentioned processing, the bus master is given a common priority for acquiring the bus use right, so that the bus use time required for the processing of the bus master can be effectively utilized while effectively utilizing the time when the common bus is not used. It can be ensured and can be executed without breaking the processing of the bus master.

As described above, in the bus arbitration method according to the second embodiment, a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In a bus arbitration method for arbitrating conflicts of rights, each of the plurality of bus masters is
A bus use permission time in which the common bus can be used within a predetermined time is preset for each of the bus masters, and each of the plurality of bus masters measures the bus use time of using the common bus. When the bus usage time exceeds the bus usage permission time for a certain bus master, a priority order for acquiring the bus usage right is assigned to each of the plurality of bus masters. The bus use time required for the processing can be secured, and the bus usage right contention can be arbitrated without breaking the processing of each bus master.

The image coding method is not limited to the above method, but may be MPEG1, MPEG2, MPEG-4,
ITU-TH. Other methods such as H.261 and Wavelet conversion may be used. Also, the audio encoding method is not limited to the above method, but may be MPEG1, MPEG2, M
PEG-4, G.I. Other methods such as 729 may be used. Further, the image coding rate and the audio coding rate are not limited to the numbers described in this embodiment.

The set value set in the bus use permission time setting unit is not limited to the time required for each bus master to transfer data, and may be another set value. Further, the set value set in the bus use permission time setting unit is not limited to the number described in this embodiment.

Note that the priority order assigned when the bus mastership acquisition requests for the common bus are simultaneously issued from the respective bus masters is not limited to the order described in this embodiment. Further, the method of measuring the bus usage time by the bus usage time measuring unit is not the method of actually measuring the time but another method such as calculation using the data transfer rate of the common bus and the data transfer amount from each bus master. May be

Further, the method of selecting a bus master candidate which gives the bus use right when the bus use right acquisition requests of the common bus are simultaneously issued from the respective bus masters to the bus arbitration device is not limited to the above method. The bus mastership is given priority to acquire the bus mastership, and when the bus master with the highest priority among the bus masters that issued the bus mastership acquisition request acquires the bus mastership and the bus master uses the bus, the priority mastership is determined. Another method such as a method using a round robin method of sequentially moving to another bus master may be used.

Further, the number of common buses is not limited to one and may be plural.

(Third Embodiment) The third embodiment of the present invention will now be described.
The embodiment will be described. FIG. 6 shows a third embodiment of the present invention.
7 is a block diagram showing the configuration of the bus arbitration device according to the embodiment of the present invention, FIG. 7A, FIG. 7B, and FIG.
8 is a flow chart of the processing of the bus arbitration method according to the third embodiment of the present invention.

The configuration of FIG. 6 in the third embodiment is basically the same as that of FIG. 1 shown in the first embodiment, but as shown in FIGS. 7 (a) to 7 (c), the bus use time is measured. Part 641
0, 6411, 6412 are different from the configuration of FIG. 1 in that they have bus usage time history storage units 740, 741, 742, respectively.

Further, the processing flow of the basic bus arbitration method according to the third embodiment is the same as the processing flow of the bus arbitration method according to the first embodiment, but each bus master has a predetermined period of time. A process of storing a history of time using the common bus and a process of optimally changing the bus use permission time of each bus master by using the stored history are added. Note that, in FIG. 8, the processing elements given the same reference numerals as those in FIG. 2 indicate the same processing elements as those in FIG.

First, regarding the configuration of the bus arbitration device according to the third embodiment of the present invention, only the blocks newly added to the bus arbitration device according to the first embodiment of the present invention will be described with reference to FIGS. 6 and 7. , And description of the same block will be omitted.

The newly added blocks are the bus use time history storage units 740 and 74 shown in FIG. 7 in the bus use time measuring units 6410, 6411 and 6412 shown in FIG.
1, 742.

Bus use time history storage units 740, 74
In Nos. 1 and 742, the bus use time used by the bus master within a predetermined time is stored at each predetermined time.

Next, regarding the processing flow of the bus arbitration method in the bus arbitration device according to the third embodiment of the present invention, the processing newly added to the bus arbitration method according to the first embodiment of the present invention. And only for different processing
Will be described and the description of the same processing will be omitted.

From the processing of issuing a bus use right acquisition request to the bus arbitration device 14 when each bus master wants to use the bus 13 in step S201 of FIG. 8, step S208 of FIG.
The process up to the process of depriving the bus mastership of the bus master currently using the bus 13 is the same as that shown in FIG.

The processing newly added to the bus arbitration method shown in FIG. 2 is the processing after the processing of step S208 of FIG. 8 and the processing of step S209 of FIG. 8 by the bus arbitration control unit 140.

After the bus arbitration control unit 140 deprives the bus mastership of the bus master currently using the bus 13 in step S208 of FIG. 8, step S801 of FIG.
In step S205 of FIG. 8, the bus usage time measuring unit, which was measuring the bus usage time, stores the measurement result in the bus usage time history storage unit.

As a result of the check in step S209 in FIG. 8, when the bus master that has acquired the bus use right in step S204 in FIG. 8 is using the bus 13, the bus use time measurement in step S205 in FIG. 8 is continued. To do. On the other hand, when the bus master has finished using the bus 13, the bus usage time measurement unit stores the measurement result in the bus usage time history storage unit in step S802 of FIG. After the storage, in step S803 of FIG. 8, the bus usage time measuring unit interrupts the measurement, and the bus arbitration control unit 140
Confirms whether the time has passed or not.

As a result of the confirmation in step S803 of FIG. 8, when the predetermined time has not passed, the bus arbitration control unit 140 waits for the bus use right acquisition request of step S206 of FIG. On the other hand, as a result of the confirmation in step S803 of FIG. 8, when the predetermined time has passed, step S8 of FIG.
In 04, the bus arbitration control unit 140 calculates the value to be set in the bus use permission time setting unit using the measurement result stored in the bus use time history storage unit provided for each bus master, and uses the bus. Set in the permission time setting section.

After setting the value in the bus use permission time setting unit in step S804 of FIG. 8, the bus arbitration control unit 140 waits for the bus use right acquisition request of step S206 of FIG.

A specific bus arbitration method in this embodiment will be described. In FIG. 6, the bus master 10 uses the G. 723.1 speech encoding unit,
It is assumed that the bus master 11 is an image encoding unit whose image encoding method is MPEG-4, and the bus master 12 is a CPU. In the system, the predetermined time is 10 ms.

The time required for each bus master to transfer data is set in the bus use permission time setting section. If the voice coding rate of the bus master 10 is 6.3 kbps, the coded voice coded data can be transferred if 1.2 ms can be used within the 10 ms. 723.1 needs to be available for 3.6 ms within the 10 ms in order to output encoded data once in 30 ms. The time required for the bus master 11 to use the bus may be 5 ms within 10 ms when the image coding rate is 32 kbps. The remaining 1.4 ms of the 10 ms is given to the bus master 12.

The bus masters 10 of the audio encoding unit are assigned in descending order of priority given when bus access right acquisition requests for a common bus are simultaneously issued from the respective bus masters.
It is assumed that they are the bus master 11 and the bus master 12 of the image encoding unit.

It is assumed that the order of the bus masters using the bus 13 and the time of using the bus 13 are as shown in FIG. 9 during the predetermined time 1 of the system.

Regarding the bus master 10, the set value of the bus use permission time setting unit 1410 and the bus use time measuring unit 14
When the measured values of 11 are compared, the measured value is equal to the set value (step S207 in FIG. 8), and the use of the bus 13 is completed.
ms is stored in the bus usage time history storage unit 740 (see FIG. 8).
Step S802). 10m after storage for a predetermined time
It is confirmed whether or not s is exceeded, but since only 3.6 ms has elapsed, the bus arbitration control unit 140 waits for a bus use right acquisition request.

As shown in FIG. 8, the bus master 12 then issues a bus use right acquisition request, and the bus master 12 acquires the bus use right and starts using the bus 13. When the set value of the bus use permission time setting unit 1412 and the measured value of the bus use time measuring unit 1422 are compared, the measured value is larger than the set value (step S207 in FIG. 8), and the use of the bus 13 is completed. In addition, the bus usage time measuring unit 1412 stores 0.9 ms in the bus usage time history storage unit 742.
(Step S802 of FIG. 8).

Finally, when the bus master 11 issues a bus use right acquisition request, the bus arbitration control unit 140 causes the bus master 11 to acquire the bus use right and starts using the bus 13.
As shown in FIG. 8, the bus master 11 uses the bus 13 longer than the set value of the bus use permission time setting unit 1411.
Therefore, the bus arbitration control unit 140 uses the bus usage time measurement unit 1
When the measured value of 421 reaches the set value of 5.0 ms
The use of the bus of the bus master 11 is stopped (step S207 in FIG. 8) (step S208 in FIG. 8). After the processing, the measured value of 5.0 ms is stored in the bus usage time history storage unit 7
The data is stored in 41 (step S801 in FIG. 8).

After the storage, since the bus mastership acquisition request is issued only from the bus master 11, the bus arbitration control unit 140 remains in the state of waiting for the bus mastership acquisition request. In the above state, when the predetermined time 1 ends, the measurement value of the bus usage time measurement unit of each bus master is initialized.
Since the bus use right is given, the 0.5 ms portion which cannot be used due to the use stop is used. After the use, when the set value of the bus use permission time setting unit 1411 and the measured value of the bus use time measuring unit 1421 are compared, the measured value is smaller than the set value, and the use of the bus 13 is finished.
The bus usage time measuring unit 1411 stores 0.5 ms in the bus usage time history storage unit 741.

After the storage, the bus arbitration control unit 140 confirms whether or not the predetermined time 1 has ended (step S803 in FIG. 8). As a result of the confirmation, since the processing is finished, the bus arbitration control unit 140 calculates the value set in the bus use permission time setting unit using the measurement result stored in each bus use time history storage unit. For the bus master 10, the value stored in the bus usage time history storage unit 740 is 3.
Since 6 ms is the same as the value of the bus use permission time setting section of 3.6 ms, no change is made. Regarding the bus master 11,
Bus use time 0.5 ms minutes Bus use permission time setting unit 7
Although longer than the set value of 41, the bus use time of the bus master 12 is 0.5 ms shorter than the set value of the bus use permission time setting section. Therefore, the bus use permission time of the bus master 12 is reduced by 0.5 ms and the amount is allocated to the time when the bus master 11 can use the bus. As a result of the allocation, the set value of the bus use permission time setting unit 741 is 5.0 ms to 5.5.
In ms, the set value of the bus use permission time setting unit 742 is 1.
It is changed from 4 ms to 0.9 ms. Even after the above process, the total bus use permission time permitted by each bus master is 10 ms, which is the same as the predetermined time.

By the above processing, the bus use time required for the bus master processing is changed by changing the bus use time required for the bus master processing according to the bus use time used by the bus master and a predetermined time. Can be ensured, and the processing of each bus master can be executed without failure.

As described above, in the bus arbitration device according to the third embodiment, a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In a bus arbitration device that arbitrates a conflict of rights, each of the plurality of bus masters is
Measuring means for respectively measuring the bus use time using the common bus, and monitoring the bus use time of each of the plurality of bus masters measured by the measuring means, and using the common bus for each bus master. Since the bus use right decision means for deciding whether or not to give the right is provided, the bus use time required for the processing of each bus master can be secured, and the processing of each bus master can be performed without failure. This has the effect of arbitrating the competition for bus usage rights.

The measurement result by the bus usage time measurement unit stored in the bus usage time history storage unit may be stored not only once but also a plurality of times. Further, the method of calculating the set value of the bus use permission time setting unit is not limited to the above calculation method. Further, the image coding method is not limited to the above-mentioned method, and MPEG1, MPEG2, MPEG-
4, ITU-TH. Other methods such as H.261 and Wavelet conversion may be used.

Further, the audio encoding method is not limited to the above-mentioned method, and MPEG1, MPEG2, MPEG-4,
G. Other methods such as 729 may be used. Further, the image coding rate and the audio coding rate are not limited to the numbers described in this embodiment. The set value set in the bus use permission time setting unit is not limited to the time required for each bus master to transfer data, and may be another set value.

The set value set in the bus use permission time setting unit is not limited to the number described in this embodiment. Further, the priority order given when the bus mastership request for the common bus is issued simultaneously from the respective bus masters is not limited to the order described in the present embodiment. Further, the method of measuring the bus usage time by the bus usage time measuring unit is not the method of actually measuring the time but another method such as calculation using the data transfer rate of the common bus and the data transfer amount from each bus master. May be

Further, the method of measuring the bus usage time by the bus usage time measuring unit is not a method of actually measuring the time, but another method such as calculation using the transfer rate of the common bus and the data transfer amount from each bus master. It may be a method.

Further, the method of selecting the candidate of the bus master that gives the bus use right when the bus use right acquisition requests of the common bus are simultaneously issued from the respective bus masters to the bus arbitration device is not limited to the above method. The bus mastership is given priority to acquire the bus mastership, and when the bus master with the highest priority among the bus masters that issued the bus mastership acquisition request acquires the bus mastership and the bus master uses the bus, the priority mastership is determined. Another method such as a method using a round robin method of sequentially moving to another bus master may be used. Also, the number of common buses may be one instead of one.

[0099]

As described above, according to the present invention (Claim 1), a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In a bus arbitration method for arbitrating bus usage right conflicts, each of the plurality of bus masters presets a bus use permission time during which the common bus can be used within a predetermined time for each of the bus masters. , Measuring the bus use time using the common bus, and if the bus use time exceeds the bus use permission time for a certain bus master among the plurality of bus masters, Since the bus usage right is not given, the bus usage time required for the processing of each bus master can be secured, and the processing of each bus master can be secured. There is an effect that it is possible to perform the arbitration of no right to use the bus contention that disrupting the.

According to the present invention (claim 2), a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In the bus arbitration method for arbitrating, each of the plurality of bus masters presets a bus use permission time for which the common bus can be used within a predetermined time for each of the bus masters, and each of the plurality of bus masters sets the common bus. The used bus use time is measured respectively, and when the bus use time exceeds the bus use permission time for a certain bus master of the plurality, the bus use right is acquired for each of the plurality of bus masters. Since the priority order for each bus master is assigned, the bus usage time required for the processing of each bus master can be secured. There is an effect that it is possible to perform arbitration without bus access conflicts that disrupting the processing register.

According to the present invention (claim 4), a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters requests the right to use the common bus. In the bus arbitration device that arbitrates, each of the plurality of bus masters measures a bus use time using the common bus, and a measuring unit that respectively measures the bus use time of each of the plurality of bus masters measured by the measuring unit. And a bus use right determining means for monitoring and determining whether or not to give the bus use right of the common bus to each of the bus masters. Therefore, the bus use time required for the processing of each bus master is determined. Can be secured,
There is an effect that it is possible to arbitrate the competition for the bus use right without breaking the processing of each bus master.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a bus arbitration device according to a first embodiment of this invention.

FIG. 2 is a flow chart of processing of a bus arbitration method in the bus arbitration device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a bus arbitration device according to a second embodiment of the present invention.

FIG. 4 is a flow chart of processing of a bus arbitration method in the bus arbitration device according to the second embodiment of the present invention.

FIG. 5 is a diagram showing an example of transfer of voice coded data in a bus arbitration device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a bus arbitration device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a bus usage time measuring unit according to a third embodiment of this invention.

FIG. 8 is a flow chart of processing of a bus arbitration method in the bus arbitration device according to the third embodiment of the present invention.

FIG. 9 is a diagram showing an example of bus use order and bus use time of a bus master in the bus arbitration device according to the third embodiment of the present invention.

[Explanation of symbols]

10, 11, 12 Bus master 13 Common bus 14 Bus arbitration unit 140 Bus arbitration control unit 1410, 1411, 1412 Bus usage permission time setting unit 1420, 1421, 1422 Bus usage time measuring unit 340 Bus usage right acquisition priority allocation unit 341 Bus Usage right acquisition request confirmation unit 740, 741, 741 Bus usage time history storage unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Kai             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5B061 BA01 BB16 BC10 GG13 GG15                       RR06

Claims (7)

[Claims] 1. A bus arbitration method in which a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters arbitrates a competition for a bus use right caused by a request for the use right of the common bus. Each bus master presets the bus use permission time that can use the common bus within a predetermined time for each bus master, and each of the plurality of bus masters measures the bus use time using the common bus, respectively, A bus arbitration method, wherein when the bus use time exceeds the bus use permission time for a certain bus master among the plurality of bus masters, the bus use right of the common bus is not given to the bus master. 2. A bus arbitration method in which a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters arbitrates a competition for a bus usage right caused by a request for the usage right of the common bus. Each bus master presets the bus use permission time that can use the common bus within a predetermined time for each bus master, and each of the plurality of bus masters measures the bus use time using the common bus, respectively, When the bus use time exceeds the bus use permission time for a certain bus master among the plurality of bus masters, a priority order for acquiring the bus use right is assigned to each of the plurality of bus masters. Bus arbitration method. 3. The bus arbitration method according to claim 1, wherein the bus use permission time of each of the plurality of bus masters is adjusted according to the measured bus use time of each of the plurality of bus masters. A featured bus arbitration method. 4. A bus arbitration device in which a plurality of bus masters are connected to a common bus, and each of the plurality of bus masters arbitrates a competition for a bus usage right caused by a request for the usage right of the common bus. Each bus master monitors the bus use time of each of the plurality of bus masters measured by the measuring unit, and the bus use time of each of the plurality of bus masters, and the common to each of the bus masters. A bus arbitration device comprising: a bus use right determining unit that determines whether or not to give a bus use right of a bus. 5. The bus arbitration device according to claim 4, wherein the bus use right determining unit determines a bus use time measured by the measuring unit of each bus master, and a bus use permission preset for each bus master. A bus arbitration device, which compares the time with the time, and does not give the bus use right of the common bus to a bus master whose bus use time exceeds the bus use permission time. 6. The bus arbitration device according to claim 4, wherein the bus use right determining unit determines a bus use time measured by the measuring unit of each bus master, and a bus use permission preset for each bus master. A bus arbitration device that compares the time with each other and, when the bus usage time exceeds the bus usage permission time, assigns a priority order for acquiring the bus usage right to each bus master. . 7. The bus arbitration device according to claim 5, further comprising a bus use permission time adjusting unit that adjusts the bus use permission time according to the bus use time of each of the bus masters measured by the measuring unit. A bus arbitration device characterized by the above.