JPH0452952A - Arbitration method between devices that use shared resources - Google Patents

Abstract

PURPOSE:To stop the arbitrating operation with a simple external circuit by transmitting the arbitration request signal of a second device to the gate circuit of a first device through the gate circuit of the second device to give priority to the first device in the use of a shared resource. CONSTITUTION:First and second devices (arbitrating circuits) 2 and 3 using a shared resource 1 are controlled by each other so that a gate circuit 7 of one device 3 is turned off by the arbitration request signal from an arbitration request holding circuit 4 of the other device 2 not to output the arbitration request signal from an arbitration request accepting circuit 9 of the device 3. At this time, the arbitration request signal of the second device 3 is transmitted to a gate circuit 6 of the first device 2 through the gate circuit 7 of the device 3 to give priority to the first device 2 over the second device 3 in occupation of the shared resource 1. When both devices 2 and 3 are not operated, a control signal is applied to gate circuits 6 and 7 of devices 2 and 3 to turn off them together. Thus, the arbitrating operation is stopped with the simple external circuit.

Description

[Detailed Description of the Invention] [Summary] Concerning an arbitration method between devices that use shared resources, only two external signal lines are required for the arbitration operation for exclusive rights to the shared resources between both devices, and the method is simple. The purpose of the external circuit is to stop the arbitration operation, and includes an arbitration request holding circuit that outputs an arbitration request signal to each of the first device and the second device that use the shared resource. This arbitration method includes an arbitration circuit consisting of an arbitration request acceptance circuit that outputs a request acceptance signal and a gate circuit that connects both circuits, and in which the arbitration request signal of each device turns off the gate circuit of the other device. The arbitration request signal of device 1 is
The arbitration request signal of the second device is transmitted to the gate circuit of the second device without passing through the device gate circuit, and the arbitration request signal of the second device is transmitted to the gate circuit of the first device via the gate circuit of the device. and has a configuration in which the first device has priority rights to use the shared resource.

[Industrial application field]

The present invention relates to a method for arbitrating resource exclusive rights of each processor when a memory or an input/output device is shared and used by a plurality of devices that use shared resources, for example, two processors.

[Conventional technology]

Conventionally, when a plurality of devices use a shared resource, there is a method 5 for arbitrating the resource exclusive rights of each device, as shown in FIGS. 6 and 7.

That is, as shown in FIG. 6, each of the first device 61 and the second device 62 has two external signal lines, a request line for requesting arbitration and an acceptance line for accepting arbitration requests.
It is connected to the arbitration circuit 63 using a total of four external signal lines. In addition, in another arbitration method, as shown in Figure 7, the second
An arbitration circuit 73 is built into the first device 72, and the external signal lines for the first device 71 are two, a request line and an acknowledge line.

[Problem to be solved by the invention]

As mentioned above, in the conventional arbitration method shown in Fig. 6, the arbitration circuit is provided outside both devices, which complicates the structure on the /'t-plane and requires four external signal lines. ,
In addition, in the arbitration method shown in FIG. 7, when the arbitration circuit 73 built in the second device 72 is checked from the outside and the arbitration operation is to be stopped, a new signal line is required. There were some problems.

Therefore, in the present invention, an arbitration request holding circuit that outputs an arbitration request signal, an arbitration request reception circuit that outputs an arbitration request acceptance signal, and both circuits are provided to each of the first device and the second device that use the shared resource. The arbitration request signal of the first device is directly transmitted from the output side of the arbitration request holding circuit to the gate circuit of the second device. The signal is transmitted to the gate circuit of the first device via the gate circuit of its own device, and each arbitration request signal turns off the gate circuit of the other device, so that the first device uses the shared resource. By giving priority to the use of shared resources, only two external signal lines are required for arbitration for the exclusive right of shared resources between both devices, and open external connections can be used for arbitration using circuits. The purpose is to be able to stop the operation.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1, 1 is a shared resource, such as a memory or an input/output device.

Reference numeral 2 denotes a first device, which includes an arbitration circuit including an arbitration request holding circuit, a gate circuit, and an arbitration request receiving circuit.

A second device 3 includes an arbitration circuit including an arbitration request holding circuit, a gate circuit, an arbitration request reception circuit, and the like.

Reference numerals 4 and 5 denote arbitration request holding circuits, from which an arbitration request signal is taken out. 1° is a gate circuit provided in the first device 2, which receives an arbitration request signal from the arbitration request holding circuit 4. is input, and the second
It is turned off by the output signal of the gate circuit provided in the device 3.

7 is a gate circuit provided in the second device N3, into which the arbitration request signal from the arbitration request holding circuit 5 is input;
It is turned off by the output signal of the arbitration request holding circuit 4 provided in the device 2.

Reference numeral 8.9 denotes an arbitration request acceptance circuit, into which the output signals of each gate circuit are input, and an arbitration request acceptance signal is taken out from its output.

Here, the arbitration request operation is performed depending on the state of each circuit when the arbitration request is generated. The arbitration request signal of the arbitration request signal 4 is applied via the signal path A (without passing through the gate circuit 6) to the gate circuit 7 of the device 3 to turn off the gate circuit.

And, since the gate circuit 6 of device 2 is on, it is installed! The arbitration request signal No. 2 is sent to the arbitration request receiving circuit 8 of the own device.
, an arbitration request acceptance signal will be output, and the device 2 will have exclusive rights to the shared resource.

Note that the arbitration request signal of the device 3, which is the output signal of the gate circuit 7, is applied to the gate circuit 6 of the device 2 via the signal path B, but this output signal is turned off as described above. In the controlled contract, even if an arbitration request signal is output from the arbitration request = M rejection 5 of the apparatus 3 after the apparatus 2 starts using the shared resource, the gate circuit 6 is turned off and the gate circuit 7 is turned on. Such a situation does not occur, and the exclusive right of the first device 2 to the shared resource 1 remains secured.

■ When the second device 3 generates an arbitration request while the first device W12 is not operating, the arbitration request signal from the arbitration point W path 5 of the device 3 enters the on-state gate circuit 7, and the output side The arbitration request signal from the device 3 is applied to the arbitration request reception circuit 9, and the arbitration request reception signal is output. As a result, device 3 has exclusive rights to the shared resource.

Note that if the arbitration request receiving circuit 9 is made into a self-holding type circuit, its output signal can be applied to the gate circuit 6 of the device 2 via the signal path C, so that the arbitration request receiving circuit 9 can be used after the device 3 starts using the shared resource. Even if the device 2 issues an arbitration request and the gate circuit 7 of the device 3 is turned off, the gate circuit 6 will not be turned off, and the exclusive right of the second device [3 with respect to the shared resource 1] will be secured. can do.

■ When the first device 2 generates an arbitration request while the second device 3 is operating, the output signal of the arbitration request reception circuit 9 of the device 3 is sent to the gate of the device 2 via the signal path C. By adding it to the circuit 6, it is possible to secure the exclusive right of the second device 3 to the shared resource 1 until the operation of the device 3 ends and the arbitration request receiving circuit 9 is reset.

■ When the second device [3 issues an arbitration request while the first device 2 is operating] As mentioned above, while the device 2 is operating, the gate circuit 7 of the device 3 is off, so the device 2 gate circuit 6 is device 3
The exclusive right of the first device 2 to the shared resource 1 is secured until the operation of the device 2 ends and the arbitration request holding circuit 4 is reset.

■ When device 2 and device 3 generate arbitration requests at the same time, a control operation to turn off the gate circuit of the other device is started by the arbitration request signal from the arbitration request holding circuit of each device, but device 2's arbitration request Gate circuit 7 (of device 3) directly controlled by the output signal of holding circuit 4
is immediately turned off, the arbitration request signal from the device 3 is not applied to the gate circuit 6 of the device 2, and therefore the gate circuit 6 is set to a specific state such as on and gate circuit 7 is off, and the shared resource is 1 is preferentially secured for the first device 2.

become that way.

Note that, as shown in FIG. 2, the gate circuit 7 provided in the second device 3 having a lower priority is connected to the first gate circuit 17 which controls the gate circuit 6 (of the device 2) to turn off with its output signal. ,
It may also be configured with a second gate circuit 27 whose output signal is applied to the arbitration request receiving circuit 9 of the device itself. At this time, both gate circuits 17 and 27 receive the same control based on the arbitration request signal from the device 2.

Alternatively, a plurality of each of the devices 2.3 may be provided and grouped, and the arbitration method may be used between a group with a high priority and a group with a low priority.

[Effect]

In the present invention, between a first device and a second device that use a shared resource, an arbitration request signal from an arbitration request holding circuit of one device turns off the get circuit of the other device. When controlling each other so that the arbitration request acceptance signal is not output from the arbitration request acceptance circuit of the device, the arbitration request signal of the second device is transmitted to the gate circuit of the first device via the gate circuit of the own device. By doing so,
A first device is given higher priority than a second device for possession of the shared resource. Further, when both devices are not operating, the arbitration operation can be stopped by applying a control signal from the outside to the gate circuits of each device to turn off both gate circuits.

〔Example〕

The present invention will be described in detail with reference to FIGS. 3 to 5.

FIG. 3 is an explanatory diagram showing an embodiment corresponding to the arbitration method shown in FIG. 1, FIG. 4 is an explanatory diagram showing an embodiment corresponding to the arbitration method shown in FIG. 2, and FIG. It is an explanatory diagram showing an example of a time chart in the example of a figure.

In FIG. 3, a first device 32a and a second device 33
is implemented as an LSI, and each device has an arbitration request holding circuit 34.
．． 35, gate circuit 36.37, arbitration request reception circuit 38
．． It is composed of 39 mag. The arbitration request holding circuits 34.35 and the arbitration request reception circuits 38.39 are each made of a D flip-flop or the like, and the gate circuits 36.37
are each composed of an AND gate.

Here, the arbitration process between the devices 32 and 33 is the same as the process in FIG. For example, when a set signal is applied to the set terminal 32S in the first device 32, at that point the D flip-flop of the arbitration request holding circuit 34 operates to output an arbitration request signal. Then, this arbitration request signal is applied to the gate circuit 37 of the second device 33 via the OR gate 40 and the signal path A, and is applied to the gate circuit (AND gate 4).
2) is turned off so that even if the second device 33 generates an arbitration request, the arbitration request signal from the arbitration request holding circuit 35 is not supplied to the arbitration request receiving circuit 39. and,
D of the arbitration request receiving circuit 38 at the next clock timing.
The flip-flop operates and outputs the arbitration request acceptance signal to terminal 3.
2E, the first device 32 can secure exclusive rights to the shared resource 31. And shared resources 3
1, a reset signal is applied to the reset terminal 32H, and the D flip 70 knobs of the arbitration request holding circuit 34 and the arbitration request reception circuit 38 are in the state before the start of arbitration creation, and an arbitration request is sent to the terminal 32E. The reception signal is no longer output, and the gate circuit 37 of the second device also returns to the on state, and the second device 3 is turned on while the first device 32 is in operation.
If the arbitration request is pending on the device 33 side, internal processing on the device 33 side is started.

Further, when a set signal is applied to the set terminal 33S in the second device 33, the circuit operation is similar to that in the first device 32, and the arbitration request signal from the arbitration request holding circuit 35 is applied to the gate circuit 37. Signal path B.

The gate circuit 3 of the first device; 32 via the OR gate 41
In addition, the gate circuit is turned off lJm. (,
(,,,,,,at the next clock timing, the arbitration request reception circuit: 390) 1] The flipflop L] operates and outputs the arbitration request and reception signal to the terminal 33E, and the device: 33 receives the shared resource 3Hr. -:) 1, at this time, the arbitration request received at terminal 33E (
=j times signal Jingo inscription, C'.

during the operation of the second device 33, the first device 32 generates an arbitration request and the gate (of the second device 33) Even when the circuit 37 is turned off, the gate circuit 36 (of the first device 32) remains switched off, and this off state is applied to the second device 33.
After the operation is completed, a reset signal from the reset terminal 33R causes the arbitration request holding circuit 35 and the arbitration request receiving circuit 39.
This continues until each of the first D flip-flops is reset, so that the second
33 occupancy rights remain secured, leaving 5. In this case, the arbitration request of the first device 32 will be put on hold.

Further, the first device 32 and the second device 1 simultaneously generate arbitration requests, and the arbitration request holding circuit 34. When a set signal is applied to each set terminal of the arbitration request holding circuit 35, the arbitration request signal is applied to both the gate and gate circuits 36 and the gate and gate circuits 37, but the output signal of the arbitration request holding circuit 34 gate circuit 37 which is directly controlled by
(AND game, g42) is turned off first. To become, the second
The arbitration request signal from the device 33 is applied to the gate circuit 361 through the OR gate 41 and the operation ends immediately, and the gate circuit 36 is turned on.

Gate circuit: 37 is turned off. Then, at the next clock timing, the D flip-flop of the arbitration request reception circuit 38 (of the first device 32) operates 1. Then, the first device 32 can start using the common resource 31 in priority over the second device 33 by outputting an arbitration request acceptance signal to the terminal 1'32E.

Further, when both the first device 32 and the second device 9133 are inactive, the external terminal 45 connects the ○R game +-44, 43
The arbitration operation can be stopped by applying an arbitration stop signal 6 to the gate circuits 36 and 37 of each device via the gate circuit 6 and turning off the gate circuit.

In addition, regarding the function of the gate circuit 37, 1. Arbitration request receiving circuit 3 receives arbitration request signal from arbitration request holding circuit 35
9 and the gate circuit 36 at the same time, the output signal of the ΔAND gate 42 is A,
The third
In the illustrated embodiment, both of these controls can be performed using only the A and ND gates 42, and the ND gate 43 may be omitted.

41st! l is in front! i:1. This is an example in which transmission control is shared between each gate circuit. In the embodiment shown in FIG. 3, the output signal of the A N D gate 1j''A (corresponding to the AND gate 43 in FIG. 7 in that the arbitration request signal from the arbitration request holding circuit 35 is directly input. That is, the transmission of the arbitration request signal from the arbitration request holding circuit 35 to the arbitration request reception circuit 39 is performed by the A, ND gate 53. The transmission to the gelt circuit 36 is controlled by an AND gate 52.

[Effects of the Invention] The present invention provides an arbitration request holding circuit that outputs an arbitration request signal to each of a first device and a second device that use a shared resource, an arbitration request receiving circuit that outputs an arbitration request acceptance signal, and An arbitration circuit consisting of a gate circuit connecting these two circuits is provided, and the arbitration request signal of the first device is directly transmitted from the output side of the arbitration request holding circuit of the M device to the gate circuit of the second device. The arbitration request signal of the second device is transmitted to the gate circuit of the first device via the gate circuit of the device, and each arbitration request signal turns off the gate circuit of the other device, The first device has priority over the second device regarding the exclusive use of shared resources, and only two external signal lines are needed between the devices for arbitration, and a simple external connection is possible. It is possible to provide an arbitration method in which the arbitration operation can be stopped using a circuit.

[Brief explanation of the drawing]

1 and 2 are diagrams explaining the principle of the present invention, and FIG. 3 is the 1I! An explanatory diagram showing an embodiment corresponding to the arbitration method of l,
FIG. 4 is an explanatory diagram showing an embodiment corresponding to the arbitration method shown in FIG. 2, FIG. 5 is an explanatory diagram showing a time chart of the arbitration method of the present invention, and FIGS. FIG. In FIG. 1, 1...shared resource 2...first device 3...second device 4.5...arbitration request holding circuit 6.7...gate circuit 8. 9...Arbitration request reception circuit 8~C Gate circuit control signal path patent applicant Pfn Co., Ltd. agent Patent attorney Long bath writer (2 others) $-Munkuni ■Other Mr. Waki Kishi, bashing country纂21!1 This book is also the principle of sun and moon - a map of the book

Claims (3)

[Claims] (1) An arbitration request holding circuit that outputs an arbitration request signal to each of the first device and the second device that use the shared resource;
An arbitration method includes an arbitration circuit including an arbitration request acceptance circuit that outputs an arbitration request acceptance signal and a gate circuit that connects both circuits, and turns off the gate circuit of the other device with the arbitration request signal of each device, the arbitration method comprising: The arbitration request signal of the first device is transmitted to the gate circuit of the second device without going through the gate circuit of the device, and the arbitration request signal of the second device is transmitted to the gate circuit of the second device without going through the gate circuit of the device. 1. An arbitration method between devices using shared resources, characterized in that the information is transmitted to a gate circuit of one device, and the first device has priority over the use of the shared resources. (2) The gate circuit is configured with an AND gate, the arbitration request holding circuit is configured with a flip-flop, and a set signal and reset signal are inputted, and the arbitration request reception circuit is configured with a flip-flop, The reset signal is inputted, an OR gate is provided in the signal path from the gate circuit of the second device to the gate circuit of the first device, and the output signal of the gate circuit of the second device is provided to the OR gate. 2. The arbitration method between devices using a shared resource according to claim 1, wherein the output signal of the arbitration request receiving circuit of the second device is added. (3) The AND gate of the second device is connected to the first AND gate, into which the arbitration request signal is input and whose output signal is transmitted to the gate circuit of the first device; 3. The arbitration method between devices using a shared resource according to claim 2, further comprising a second AND gate which is transmitted to an arbitration request receiving circuit of the device itself.