SU1388865A2 - Device for servicing requests - Google Patents

Abstract

The invention relates to computing and can be used in computing systems. The purpose of the invention is to increase the functional reliability by eliminating the POSSIBILITY of violation of the discipline of cyclical survey of objects. The device can operate in two modes specified by the binary code of the numbers in the second register. In one mode, with the zero code in the second register, the subscriber is selected for service by cyclically polling the subscriber who submitted the requests. In the other mode, in the second register, the binary code of the number of the subscriber having the highest priority is set. In this case, the polling of subscribers begins in each cycle from the subscriber whose number is taken in the second register. 1 il. with s

Description

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The invention relates to computing, can be used in computing systems and is additional to the author. St. No. 1196870.

The aim of the invention is to increase the functional reliability of the device by eliminating the possibility of violation of the discipline of cyclic polling of subscribers.

The drawing shows a block diagram of the device.

The device contains a register 1 ,, group of elements AND 2, sj eMeHT OR 3, decoder 4, delay element 5 ,, element AND 6, element OR 7, counter, 8, element OR 9, element And 10, trigger 1 1 blocking, element NOT 12, delay element 13, driver 14 pulses, EL; ment OR 15, register 16, element 17, trigger 18, group of response inputs-19 devices, group of device request inputs 20, device setup input 21, signal output 22 Devices, groups: Pu outputs 23 devices, a group of co- (Dual inputs 24 devices, a clock input 25 devices and inputs 26 start devices but.

Consider the principles of construction and operation of the device.

The device provides service for the sources of requests both in the cyclic polling mode, starting each next cycle with the source polling, the number of which is one more than the source number served in the previous cycle, and in the relative priority mode, when the search starts in each cycle with the source polling, which has the highest authority.

The selection of the polling mode is determined by the state of register 16, from where the subscriber's binary code is transmitted to counter 8. In the first case, a zero code is received in register 16, and in the second case the binary code of the subscriber number.

To bring the device back to its initial state, input 21 is given a pulse, through which triggers 18 and 11 and register 1 are set to state O. In addition, through this pulse, through the element OR 7 fed to the control input of counter 8, the contents of register 16 is transmitted to counter 8. Let requests from the 1st and 2nd subscriber be fixed

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respectively, in the 1st and 2nd bits of register 1, and in register 16, the zero code was set.

After the device returns to its initial state, if it is necessary to service the requests, input 26 receives a pulse, which triggers 18 and 11 are set to the first state.

After setting to 1 flip-flop 11, a single signal level from its single output appears at the third inputs of the And 2 elements after a certain time, determined by the delay element 5. The delay time by the delay element 5 is selected by: a move from reliable reception of a pulse from the output of the element OR 3 by the serving device.

Since the contents of counter 8 are zero, there are no signals on all outputs of the decoder 4. Therefore, at the output of the IL 3 element, a zero signal is generated, which opened element AND 17 on the inverse input. Since this element is also opened with a single signal from the single output of the trigger 18, the binary pulse of the unit is formed by the first pulse from output 25. In this case, at the first output of the decoder 4, a single signal occurs, which opens the element AND 2, and at the input of the element OR 3, a single signal is generated, which arrives at the output 22. By a positive differential, the pulse shaper 14 is triggered, the trigger 18 is closed and the element And 17 on the inverse input. According to the signal from the code 22, the binary code of the first subscriber from the outputs 23 is received in the serving device. The delayed signal from the pulse generator 14 by the delay element 13 is set to the state O of the trigger 11 and, since the AND 10 element is opened with a single signal from the output of the HE 12 element, one is added to the counter 8 through the OR 9 element. The contents of counter 8 become two. At the same time, at the second output of the decoder 4, a single signal is formed, which opens element 2 at the second input, which is open at the first input with a single signal from the output of the second register bit 1. But since trigger 11 is set to state O, the zero signal from single him

output AND 2 is closed at the third input, so a single signal from the output of the element OR 3 is removed. The delay time by the delay element 13 is determined by the reliability of receiving in the serving device the binary code of the subscriber number from the outputs 21.

After the service of the first subscriber is completed, its request is removed by a pulse at input 19. The next polling cycle starts after a pulse is applied to input 26. Since element 2 is opened by a delayed single signal from a single output of trigger 11, the single signal from the output of element OR 3 closes down on the inverse input element AND 17 signal from output 25 to the counting input of the counter 8. In the future, the operation of the device is similar to that considered. As a result of polling the second subscriber, a binary code of the number three is formed in the counter, from which the polling begins in the next cycle.

After completing the service of the second subscriber, at input 19, the response signal is set, which is set to the second bit of register 1. When the next pulse arrives at input 26, the flip-flops 18 and 11 are set to 1 and, since the output of the OR 3 element is zero, element 17 is open at the inverse input, and counter 17 is sent to the counting input of counter 8, and elements 17 and OR 9 are clocked from output 25. The polling of subscribers begins with the number, for the larger unit served in the second cycle.

Thus, the presence of the blocking trigger 11 and the delay element 5 ensures the formation of a positive difference of a single signal by the element OR 3 when there are requests to the adjacent bits of the register 1, which is necessary to start the pulse generator 14 pulses.

In the service mode with relative priority, the operation of the device differs from the operation of the device in the cyclic polling mode and consists of the following.

At the beginning, the binary code of the subscriber who is assigned the highest priority, i.e. priori code

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theta corresponds to the subscriber's number code. In addition, each next cycle of operation of the device begins with a survey of this subscriber. The signal from output 21 is set to state O register 1 and triggers 18 and 11, and the binary code of the subscriber number from register 16 is transmitted to counter 8.

The delayed pulse of the driver 14 through the open element AND 6 with a single signal from the output of the element OR 15 and through the element OR 7, arriving at the control input of the counter S, the binary code of the subscriber number from the register 16 is transmitted to the counter 8. Thereby ensures the interrogation of subscribers in the next cycle from the subscriber having the highest n priority. In this mode, the AND 10 element is closed with a zero signal from the output of the NOT 12 element, therefore only the clock pulses from the output 25 through the AND 17 element can be sent through the OR 9 element to the counting input of counter 8.

In the proposed device, due to the presence of the blocking trigger 11 and the delay element 5, it is possible to create the starting conditioner 14 pulses for any combination of requests in register 1, which eliminates the possibility of a violation of the cyclic polling discipline.

Claims (1)

Invention Formula Device for servicing requests for auth. St. No. 1196870, characterized in that, in order to increase functional reliability by eliminating the possibility of violating the cyclical discipline of polling subscribers, a blocking trigger and an additional delay element, the output of which is connected to the third inputs of the And group elements, are added to the additional delay element to the single output of the blocking trigger, the zero input of which is connected to the output of the delay element, the single input of the trigger of the blocking connected to the input start of the device, the output of the second element OR is connected to the inverse input of the first element AND, the installation input of the blocking trigger is connected to the installation input of the device. 1Vp 5,