JPS6084653A - Daisy chain type interruption requesting circuit - Google Patents

Abstract

PURPOSE:To prevent the influence of a power break of one unit from extending to other chained units by providing a relay contact which forms a short circuit between the input side and output side of the interruption permission line of each I/O unit. CONSTITUTION:Relay contacts S1, S2... make direct short-circuit connections between input sides G1, G2... and output sides G2, G3... of interruption permission lines of respective I/O units U1, U2.... Those relay contacts S1, S2... are normally closed contacts and closed while power sources P1, P2... are off. When the power sources P1, P2... generate outputs normally, the relays S1, S2... are broken with their outputs. Consequently, only the I/O unit whose power source is broken is stopped with a function.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a daisy-chain interrupt request circuit for processing multiple interrupt requests with priority.

A conventional general configuration of a daisy-chain interrupt request circuit is shown in FIG. The center of the computer is the CPU
(central processing unit) / and memory 2, etc., and various input/output units μ are directly connected to the CPU bus 3.
A plurality of 10 units U/-Un are connected to the bus O. The 10 units U/--Un of this process are handled by a daisy-chain interrupt circuit.

Interrupt request output terminals R/~Rn (logic output terminals 0/~C) of U/~Un are
It is hooked up to a common interrupt request line included in the bus B, and connected to the OPU/ via the controller S of the machine 10. When the interrupt request signal in a certain I10 unit Ul (1-/~n) reaches the R level or the H level, the logic becomes 0.
1's output R1 becomes L level, and an interrupt request is transmitted to CPU/.

The interrupt permission signal from OPU/ goes through the engineering 10 controller S and the engineering 10 bus O, and then goes to the interrupt permission line ()/ in a chain structure via the logic group ()AI and B1 in each engineering 10 unit U/~Un. %Gn. That is, the interrupt permission signal (H level) is first transmitted to the highest priority unit U/ via the permission line G/, and the output 0/ of the logic gate Al becomes L level. When this process is performed (R8/ is H level), the output of logic gate B/, that is, σ, can be m
The signal c+2 remains at the L level, and interrupt permission ('gi is not transmitted to the units U-U of the 10th unit Ul).

Mari, engineering 10 units) If U/ is rejected after 1 te of interrupt request (R8/ is L level), the output of logic gate B/ is H level, which takes the next priority based on permission line G2. 10 unins) [Transmitted to J, 2.

In this way, in the chain configuration of the permission lines G/ to Gn, the unit closest to the CPU 1 has the highest priority, and the lower the priority is, the closer to the end of the chain. The operating principle of the daisy chain is that the interrupt permission signal for the low priority unit is transmitted through the chain only when no interrupt request is made in the high priority unit.

The conventional daisy-chain type interrupt JM ice circuit described above has the following problems. 8181 In figure P/~P
n indicates the operation 'T & Lox of each I10 unit U/-Un, and pl is an independent wire device that converts AC power into a predetermined Do power. For example, if rhsp/ of unit 10) U/ breaks down and there is no DC output,
The logical groups (A/, B/, O/ in this unit U/) become inoperable. logic) A/ and B/ are interrupt enable lines Gl
- Since it is inserted in the middle of the Gr1 chain, if it stops working, it will be in the same state as if the chain was broken.

In other words, the interrupt request signal from OFU/ is not transmitted to the metalworking units U/--Un, and the entire system stops functioning. Even if the power supply Pi of a VC unit (Unison) with a low priority is cut off, the same phenomenon described above occurs for units with a lower priority. In addition, not only when the power supply P1 breaks down, but also when replacing the printed board of the sx/" unit Ul, the power supply P1 of the unit υ1
The same thing happens when you intentionally turn off 1, resulting in the same system failure situation as described above.

In this way, in conventional circuits, when the power to one unit is cut off, not only does the function of that unit stop, but it is also the same as if the chain had been broken in that unit, and the functions of other units also stop. I'll let you.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to
An object of the present invention is to provide a daisy-chain type interrupt request circuit that does not affect other units connected in a chain.

In order to achieve the above object, the present invention provides a relay contact for short-circuiting and directly connecting the input side and output side of the interrupt permission line of 10 units of each factory, and the power output of 10 units of each factory is The present invention is characterized in that each of the relay contacts is opened in a normal state, and is closed in a case where the electrolytic corrosion output is cut off.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows an embodiment of the present invention, in which the same or corresponding components as in the conventional configuration of FIG. 1 are given the same reference numerals. The configuration of the computer side and the basic configuration of the daisy-chain type interrupt request circuit are the same as those of the prior art, so the above description will be used for the same parts, and no redundant explanation will be given.

In addition, in FIG. 2, only the units U/ and Ul are shown, but it goes without saying that there may be many more units, and the description will be made assuming that there are 10 units of units up to U/.

In the daisy-chain type interrupt request circuit according to the present invention, the input side G1 of the interrupt enable line of 10 units for each process is
A relay contact s1 is provided for completely short-circuiting and directly connecting the output side G1+ and the output side G1+. That is, the input terminal of the logic gate A1 and the output terminal of the logic gate A1 are connected through the relay contact S1. The relay contact S1 is a normally closed contact such as a reed relay or a mercury relay, and the contact s1 is closed when the output of the power source P1 is cut off. When the output of the power source P1 is normally generated, the output E1 drives the relay contact S1 to open the circuit.

Further, each power source P1 is provided with a power switch SWI.

For example, when replacing the printed board inside the unit,
This switch SWi can turn off the power mP1. Furthermore, when the electric power (Jl, Pl) is turned off or the telephone P1 is cut off due to an abnormality, the power cutoff signal F1 is output from this power supply P1.Each power cutoff signal F1
is input to the 10 units 4' directly connected to the CPU bus 3, and notifies the CPU of the power outage of each unit U1.

In the above configuration, if the electric wire 1211 P' = Pn of the metalwork 10 Unison) U/~Un is normal, the relay contacts S/~Sn are all open, and in this state, the conventional circuit shown in FIG. works exactly the same.

Here, for example, suppose that the power (IIP/) of I10 unit U, which has the highest priority, is turned off or disconnected. Then, this unit) A/, , B/IC/ operates and the logic in U/ is turned off. However, a relay contact is used instead! 3/ is closed, and interrupt permission lines G/ and 02 are directly connected.

Therefore, even if the function of the CPU 10 unit U/ stops, the chain is maintained, and the CPU
The interrupt permission signal from / is transmitted. In other words, IJ, 2~Un function normally, and a total system down is avoided. Also, I10 unit ≠ O through 2
Since the notification is sent to PU/, CPU/ is 10 units U.
Do not access /.

The above operation is the same when other power HPs are turned off or disconnected.

As explained in detail above, according to the daisy-chain type interrupt request circuit according to the present invention, even if the electric trace of one unit among a plurality of units connected by a chain is turned off or disconnected, the function is not maintained. Only that unit is stopped; the chain remains intact and other units are not affected.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram including a conventional daisy chain type interrupt request circuit, and FIG. 2 is a system configuration diagram including a daisy chain type interrupt request circuit according to the present invention. /...OPU, λ...Memory, 3...OPU bus% Hiro...Engineering 10 units, S...Engineering 10 controllers, t...Engineering 10 buses, ul (1= /~n )−
I/O unit, Pl...Electrical unit R1...Interrupt request output terminal, G1...Interrupt permission line, Al, B1,
01...Logic gate, Sl...Relay contact %F Sat.
...Power cutoff signal, SWl...power switch.

Claims (1)

[Claims] (Multiple I
Daisy-chain type in which the /O unit is hooked up and the interrupt permission signal from the CPTJ is transmitted to the interrupt permission line of the chain structure via the logic gates in each of the 10 units, and priority processing of interrupts is performed. In the interrupt request circuit, a relay contact is provided to directly connect the input side and output side of the interrupt permission line of each of the 10 units in each process by short-circuiting.
A cheesy chain type interrupt characterized in that each of the relay contacts is opened when the power output of the 0 unit is normal, and is configured such that each of the relay contacts is closed when the power output is cut off. request circuit.