RU1787285C - Multichannel device for user connection to common bus - Google Patents

Abstract

The invention relates to computer and communications technology and can be used in LANs and multi-machine computing systems to control access to a common backbone. The purpose of the invention is to increase the reliability of the device in operation by eliminating the possibility of re-capturing the common trunk by one subscriber. An And element is introduced into a multi-channel device for connecting subscribers to a common trunk, and two pulse shapers, a single vibrator, a delay element, an OR element, an amplifier, and a transmission control unit, are introduced into each channel. The device allows for priority exchange between subscribers with the organization of a decentralized arbitration of requests for the subsequent capture of the common highway during the current transmission of information with the exception of the possibility of re-capturing the common trunk by one subscriber f-ly, 2 ill. AND

Description

The invention relates to computer and communications technology and can be used in LANs and multi-machine computing systems to control access to a common backbone.

The aim of the invention is to increase the reliability of the device in operation by eliminating the possibility of re-capture the common trunk by one subscriber.

In FIG. a functional diagram of the device is presented; in FIG. 2 - block diagram of the control block.

The device contains an element I1, form. pulse train 2, counter 3, trigger 4, pulse shaper 5, element 6, block 7 for monitoring the presence of transmission, element 8, single vibrator 9, 10 pulse generator, element OR 11, trigger 12, element

delays 13, AND element 14, trigger 15, amplifier 16, channel 17, common line 18, polling input 19, installation input 20, request input 21, capture confirmation input 22, polling output 23, input 24 of control unit 7, output of 25 unit 7 control

 The control unit 7 (Fig. 2) contains isolation elements 26 and 28, an RC chain 27, and a trigger 29.

The device operates as follows.

At the first time after the power is turned on, there is no request signal to capture the common resource in all channels 17, which corresponds to a low signal level at the input 21 of the request of each channel 17. Thus, triggers 4 and 15 are set to the initial (zero) coVI

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standing. In addition, at the time of formation of the initial installation system signal, which is input to input 20 in each channel, trigger 12 and counter 3 are set to their initial state. At the time of recording the initial setup signal, the output of the common element 17 for all channels 17 will generate a positive voltage drop, which through the pulse shaper 5 is fed to the triggering input of the one-shot 9. From the inverse output of the one-shot 9, a negative pulse is transmitted through the And 14 and the amplifier 16 will go to the output 23 of the survey of the first channel 17; then this pulse will go to the input of the next channel 17, etc. From the output 23 of the polling of the last channel 17, the polling pulse is fed to the second input of the element And 1 common to all channels and from its output to the input 19 of the polling of the first channel 17. In this way, the channels 17 are polled.

At the moment of polling each channel 17 from the direct output of the one-shot 9, a positive pulse arrives at the clock input of trigger 15. However, trigger 15 does not change its state, since it is blocked at the input of the initial setting by the absence of a signal at the input 21 of the request. In addition, a positive pulse from the direct output of the one-shot 9 through the delay element 13 and the OR element 11 is fed to the clock input of the second trigger 12, confirming its zero state. If there is a request signal at the input 21 of the request at the moment of operation of the single-vibrator 9, the trigger 15 will switch to the single state and the low-level potential from its inverse output will block the further propagation of the polling pulse through the element And 14. From the direct output of the trigger 15, the high-level signal arrives at the second input of AND element 8, allowing the clock frequency to pass from the output of the generator 10 to the counting input of the counter 3. In the case of transmitting information along a common 18 highway, there are 2 pulses at the output of the pulse shaper sequence of pulses, whose frequency is equal to the carrier frequency of the transmitter.

For each pulse at the output of the pulse shaper 2, the counter 3 is reset. Thus, the presence of a clock sequence at the counting input of the counter 3 comp. is affected by the presence of a clock pulse train at its installation input, i.e. at the time of the transmission of information along the common highway 18, the counter 3 is kept in its initial state. In the absence of transmission on a common trunk

18, at the output of the pulse shaper 2, a resolving potential is set for the counter mode of operation of the counter 3. The conversion factor of the counter 3 determines the minimum pause between adjacent transmissions of information on a common highway.

The pulse from the output of the overflow counter 3 is fed to the clock input of the trigger

0 4, setting it to a single state. In this case, the low potential from the inverted output of the trigger 4 goes to the output 22 of the confirmation of the capture of this channel 17. allowing the subscriber to transmit information.

5 In addition, the same low-level signal through the And 6 element sets the trigger 15 to its initial state and the trigger 12 at the input of the installation in 1 - to the single state. At the same time, low potential from direct output

0 trigger 15 blocks the passage of the clock frequency through the element And 8, and the low potential from the inverse output of the trigger 12 goes to the third input of the element And 6. At the time of installation of the trigger 15 in the original

5, the state at the output of element And 14, a positive voltage drop will be formed, which through the amplifier 16 will go to the polling input 19 of the next channel, i.e. the channel polling process will resume when the subscriber who has captured the common trunk starts transmitting information.

If any of the subscribers sets a request signal at the input 21 of the request

5 of its channel 17, then, as considered

- above, this request will be satisfied only after the end of the current transmission cycle. In the absence of requests in channels 17, a circular polling of all

0 channels. At the same time, the polling pulse entering the channel 17 of the subscriber conducting the transmission will not change the state of the elements of this channel formed at the time of the capture of the common trunk.

5 After the end of the transmission session, the subscriber removes the request signal, which corresponds to the appearance of a low potential at the input 21 of the request of this channel 17. In this case, trigger 4 is set to the initial (zero) state and a high level signal from its inverse output unlocks the trigger. 12 at the input of the installation to 1. If, at the same time, the subscriber of this channel 17 sets the request signal again, then when polling this

5 channels of capture of the common highway 18 will not happen, since the trigger 15 will be kept in the zero state by the signal

low level at the input of the installation in O, coming to the third input of the element And 3 from the inverse output of the trigger 12. In this

In this case, the trigger 12 will be restored to its original state after the positive pulse is applied to the clock input of the trigger 15 at a time interval determined by the delay time of the pulse passing through the delay element 13 and the OR element 11. This ensures that one polling cycle will be skipped after the end of transmission if there is no transmission requests in other channels 17.

If there is a request in one of the remaining channels, the transmission of information by the subscriber of this channel will begin after the previous transmission ends at a time interval determined by the conversion factor of counter 3. At the same time, the beginning of the transmission of information initializes the appearance of a positive pulse at the output of the control unit 7. The pulse from the output of the control unit 7 through the OR element 11 is supplied to the clock input of the trigger 12, setting it to its initial state, determined by the state of its information input. The channel returns to its original state and may participate in further arbitration of requests.

Claims (2)

SUMMARY OF THE INVENTION 1. A multi-channel device for connecting subscribers to a common trunk, comprising a pulse generator, a counter, three triggers, three AND elements in each channel, the request input of the device being connected to the R input of the first trigger, the C input of which is connected to the overflow output a counter, whose counter input is connected to the output of the first element And, the first input of which is connected to the output of the pulse generator, the inverse output of the first trigger is connected to the first input of the second element And, the second input of which is connected is connected with the inverse output of the second trigger, and the output is connected to the R-input of the third trigger, the inverse output of which is connected to the first input of the third element And, characterized in that, in order to increase its reliability in operation by eliminating the possibility of re-capturing the common trunk by one subscriber , element And is introduced into it, and into each channel are two pulse shapers, a single vibrator, a delay element, an element OR, an amplifier and a transmission presence control unit, wherein the first input of the And element is connected to the installation inputs of the first pulse shaper, to the R-input of the second trigger and to the input. The initial installation of the device, the output of the And element is connected to the input of the second pulse shaper of the first channel, the output of amplifier 1 -th (I 1 ... (p-1), p-number of subscribers) channel is connected to the input of the second pulse former (I + 1) of the channel, the output of the amplifier of the last channel is connected to the second input of the And element, in each channel my single vibrator output is connected n with the C-input of the third trigger, the second input of the third element And is connected to the inverse output of the one-shot, the input of the start of the first pulse shaper is connected to a common highway, the output of the first pulse shaper is connected to the input of the counter installation and the input of the transmission presence control unit, the third input of the second element And connected to the request input of the device, the inverse output of the first trigger is connected to the installation input in 1 of the second trigger and to the output Confirmation of capture of the device, the information input of the second trigger with is single with the logical O bus of the device, and its clock input is connected to the output of the OR element, the first input of which is connected to the output of the transmission presence control unit, and the second input is connected to the output of the delay element, the input of which is connected to the direct output of the single-vibrator, the information inputs of the first and the third flip-flops are connected to the bus of the logical unit of the device, the direct output of the third flip-flop is connected to the second input of the first element And, the output of the second pulse former is connected to the triggering input of the one-shot, the third output on element and connected to the input of the amplifier. 2. The device according to claim 1, with the exception that the transmission control unit contains a trigger, two isolation elements and an RC chain, the input of the unit being connected to the trigger C input and through the first isolation element with the input of the RC circuit, the output of which through the second isolation element is connected to the R-input of the trigger, the output of which is connected to the output of the block. FIG. 2.