JPH0227461A - Data transfer controller - Google Patents

Abstract

PURPOSE:To acquire an internal bus after the designated time even at the time of a low priority agent by executing a bus waiting decision, a priority changing and a bus arbitration. CONSTITUTION:A bus arbitration part 4 is provided with a bus waiting deciding part 5, a priority changing means 6 and a bus arbitrating means 7. The bus waiting deciding means 5 decides the condition in which the use of an internal bus 8 is not permitted and that a bus request signal is continued only for the designated time, and designates said bus request signal. A priority changing means 6 gives the best priority to the bus requesting signal designated by the bus waiting deciding means 5. Thus, since the use of the internal bus 8 is permitted for the highest order priority bus request signal, the internal bus can be obtained even by agents 1-3 of the low priority.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in data transfer control devices.

Especially regarding that internal bus arbitration.

(Prior Art) Conventionally, in this type of data transfer control device, internal bus arbitration is performed according to fixed priorities of each agent connected to the internal bus.

(Section III on which the invention is focused) In the internal bus arbitration in the conventional data transfer control equipment described above, the priority of the bus request signal is fixed for each agent, so the agent with a high priority If the bus continues to be used, a low priority agent cannot take the internal bus. When the use is not permitted, it is determined that the bus request signal continues for a specified time, and the corresponding bus request signal continues.

By setting the priority of the t bus request signal specified by the bus wait determination as the highest priority, and further allowing the use of the internal bus for the bus request signal with the highest priority, the above disadvantages can be solved. The object of the present invention is to provide a nine-data transfer control device configured so that even low-priority agents can use the internal bus.

(Tth Means for Solving the Problem) A data transfer control device according to the present invention includes an internal bus, a plurality of agents connected to the internal bus, and a bus arbitration section connected to a plurality of agents via the internal bus. and is configured so that each agent can send a bus request signal to the bus arbitration unit.

In the above configuration, the bus arbitration section includes a bus waiting determination means;
The system is configured to include a priority changing means and a bus arbitration means.

The bus waiting determination means determines whether the bus request signal continues for a specified time in a state where use of the internal bus is not permitted, and specifies the bus request signal.
The priority changing means is designed to give the highest priority to the t-bus request signal specified by the bus waiting determination means.

The bus arbitration means is the tth one that permits use of the internal bus to the bus request signal given the highest priority by the priority changing means.

(Example〕 Next, one embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a data transfer control device according to the present invention, and FIG. 2 is a time chart showing the operation of step 7.

In FIG. 1, l is the first agent.

2 is the second agent, 3 is the third agent, 4
5 is a bus arbitration unit, and 5 is a bus waiting determination unit.

6 is a priority changing means, 7 is a bus arbitration means, 8 is an internal bus, 9 is a first bus request signal line, and 10 is a second bus request signal line.

11 is a third bus request signal line, 12 is a first path permission signal line, 13 is a second bus permission signal line, 1
4 is a third path use permission signal line.

2, the state on the first bus request signal line 9 of the first agent 1 is l", and the state on the second bus request signal line lO of the second agent 2 is '1". It is.

At this time, the bus arbitration unit 4 gives the first bus use permission signal to the first agent 1 having a higher priority via the signal line 12, and the first agent 1 is using the internal bus 8.

2 in Figure 2, the state on the bus request signal line 9 of the first agent 1f41 is O''', tl/!,
2, the second bus request signal line 10 of agent 2
The state on the third bus request signal line 11 of the third agent 3 is "1". At this time, the bus arbitration unit 4 gives a bus use permission signal to the second agent 2J having a higher priority via the signal line 13i. At this time, the first agent 1 and the second agent 2 continue to occupy the internal bus 8 from point 2 in FIG. 2 to point 2 in FIG.

2, the pass request request unit 10 of @3 has been waiting for the bus acquisition for the specified time, and this is set as 1544J in the bus waiting determination means 5.

Therefore, the priority changing means 6 sets the priority of the bus request signal on the third bus request signal line 1O to the highest level, and the bus arbitration means 7 sends a bus use permission signal to the third agent 3, thereby granting bus use permission to the third agent 3.
Give J.

In this way, the upper agent uses internal bus 8? Even if occupied, subordinate agents can also obtain internal bus 8?1-11'J after a specified time.

(!! 6 bright effects) As explained above, the present invention has data transfer control fefu
? By performing bus waiting determination, priority change, bus arbitration, and arranging in the internal bus arbitration unit that constitutes f-, even an agent with a low priority can acquire 1 internal bus after a specified time. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a data transfer control device according to the present invention. FIG. 2 is a time chart showing the operation of the data transfer control device shown in FIG. 1-3...Agent 4-a4su U4 stop WA5
... Bus waiting determination means 6 ... Priority changing means 7 ... Bus arbitration means 8 ... Internal buses 9 to 1
4...Signal line

Claims (1)

[Claims] The device includes an internal bus, a plurality of agents connected to the internal bus, and a bus arbitration section connected to the plurality of agents via the internal bus, and a bus arbitration section is provided from each of the agents to the bus arbitration section. In a data transfer control device configured to be able to send a request signal,
The bus arbitration unit determines that the bus request signal continues for a specified time in a state where use of the internal bus is not permitted, and also includes a bus wait determination means for specifying the bus request signal, and a bus wait determination unit for determining the bus request signal. a priority changing means for giving the highest priority to the bus request signal specified by the means; and a priority changing means for giving the highest priority to the bus request signal specified by the priority changing means; 1. A data transfer control device comprising: bus arbitration means for permitting use.