SU1698889A1 - Priority two-port device - Google Patents

Abstract

The invention relates to computing and can be used to access two users to a common resource. The purpose of the invention is to reduce the amount of equipment. The two-input priority device contains decoder 1, triggers 2 and 3, match element 4. In the case of simultaneous presence of active signals at the device inputs, a single signal at output 1.3 of the decoder 1 sets trigger 2 to one, with which matching element 4 blocks the decoder 1, 1 or 10 .

Description

The invention relates to computing and can be used to access two users to a common resource.

A two-input device is known that contains a NOT element, two OR elements, a threshold element, two delay control blocks, and a delay element.

The disadvantages are the complexity and lack of reliability.

The closest to the proposed technical entity is a two-input device containing a decoder, two single vibrators and two flip-flops, the first and second request inputs of the device being connected to the zero inputs of the first and second triggers, respectively, and the first and second information inputs of the decoder, the first output of which is connected to the first single input of the first trigger, whose direct output is the first output of the device, the second output of the decoder is connected to the single input of the second trigger, directly The output of which is the second output of the device, the third output of the decoder is connected to the input of the first one-oscillator, the output of which is connected to the start input of the second one-oscillator, the output of which is connected to the second single input of the first trigger, the inverse output of the second one-oscillator.

The disadvantage is a large amount of equipment.

The purpose of the invention is to reduce the equipment while maintaining the function of the device.

This goal is achieved by the fact that a two-input device containing two triggers and a decoder, the first and second request inputs of the device are connected to zero inputs of the first and second triggers, respectively, and the first and second information inputs of the decoder, the first output of which is connected to the first single input of the first trigger 00 00 00

Yu

Pa, the direct output of which is the first output of the device, the second output of the decoder is connected to the single input of the second trigger, the direct output of which is the second output of the device, contains a matching element, the output of which is connected to the control input of the decoder, the first and second inputs are connected with inverse outputs, respectively, of the first and second triggers, in which the inverse output is connected to the second single input of the first trigger, the third output of the decoder is connected to the second single input of the first trigger .

The drawing shows a functional diagram of the proposed device.

The device contains a decoder 1, the first trigger 2, the second trigger 3, the match element 4, the first and second request inputs 5 and b of the device, the first and second outputs 7 and 8 of the device. Inputs 5 and 6 are connected to the information inputs of the decoder 1 and to the zero inputs of the triggers 2 and 3. The direct outputs of the triggers 2 and 3 are connected to the outputs 7 and 8, the inverse outputs are connected to the control input of the decoder 1 via the matching element 4. First, second and the third outputs of the decoder

1 are connected respectively to the first single input of trigger 2, single input of trigger 3 and the second single input of trigger 2, Second zero input of the trigger

2connected to inverse trigger output 3.

The device works as follows.

In the initial state at inputs 5 and 6, the request signals are missing / there are zero levels, which set trigger 2 to zero states, which are present at outputs 7 and 8. Unit levels of inverse outputs of trigger 2 and 3 pass through the coincidence element 4 unit level to the control input of the decoder 1, allowing the decoder 1 to decipher the states of the inputs 5 and 6. On the first, second and third outputs of the decoder 1 are zero levels.

The request signals arrive at inputs 5 and 6 of the device in the form of levels 1. When a request is received at input 5, output 1.1 of decoder 1 shows a single signal that sets trigger 2 to one state. A single signal appears at the output 7 of the device, allowing the processing of the request received at input 5. At the same time, the zero level of the inverse output of trigger 2, the passage of the coincidence element 4, blocks the decoder 1, which removes the single signal from output 1.1. Upon completion of processing the request for input 5, the zero level arrives, which returns trigger 2 to the initial state.

When a request is received for input b, the device functions in the same way.

If, after a request to enter 5 is received, after a time exceeding the triggering of trigger 2, an input request is received

0 6. The device operates as follows.

At output 1.1 of the decoder 1, a pulse appears, the duration of which is sufficient to trigger the trigger 2, and

5, output 7, a service enable signal appears. At the end of the pulse at output 1.1, at output 1.3 of decoder 1, a single signal appears, which repeats the state of trigger 2. Appeared

0, the signal at the output of trigger 2 blocks the coincidence element 4, decoder 1. At the end of the service request for input 5, a zero signal appears at this input, which sets in O a trigger 2 and

5 returns a match element 4 and a decoder 1 to its original state. At output 1.2 of the decoder 1, a single signal appears, which sets in 1 a trigger 3, which enables the request service,

0 received at the input device b.

With simultaneous requests for inputs 5 and b of the device, or, if this time is short compared with the response time of the circuit elements, the device

5 works as follows.

When a request for input b is slightly ahead, a short pulse is generated at output 1.2 of decoder 1 with a level 1 or with a level that has not reached

0 full unit level. If this pulse does not trigger the trigger 3, then the signal at the output 1.3 of the decoder 1 sets the trigger 2 to one, which allows the processing of the request

5 at input 5, and the level O of the inverse output of flip-flop 2 blocks the decoder 1. Upon completion of its service, flip-flop 2 is set to O, and flip-flop 3 is set to output 1.2 of the decoder 1

0 to 1 and allows servicing of the request at input 6 of the device. At the end of its service, the device returns to its original state.

If this impulse triggers trigger 3, the latter blocks decoder 1 and trigger 2 and allows the request to be serviced at input 6. At the end of its service, trigger 3 is set to O, and trigger 2 by output 1.1 of the decoder 1 is set

in G and allows the service request for 5 devices.

At the end of its service, the device returns to its original state.

Thus, the proposed device in comparison with the prototype contains a smaller amount of equipment and, in operation, repeats the function of the prototype.

Claims (1)

Claims of the invention A two-input priority device comprising two triggers and a decoder, the first request input of the device connected to the first zero input of the first trigger and the first information input of the decoder, the second request input of the device connected to the second information input of the decoder and zero input five the house of the second trigger / first output of the decoder - with the first single input of the first trigger, the direct output of which is the first output of the device, the second output of the decoder is connected to the single input of the second trigger, the direct output of which is the second output of the device, characterized in that in order to reduce the amount of equipment, the device contains a coincidence element, the output of which is connected to the gate input of the decoder, the inverse outputs of the first and second triggers are connected to the inputs of the coincidence element, the third the output of the decoder - with the second unit input of the first trigger, the second zero input of which is connected to the inverse output of the second trigger.