SU860073A2 - Device for priority connection of data sources to the bus - Google Patents

Description

(54) DEVICE FOR PRIORITY CONNECTION OF INFORMATION Sources to the TRACK

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The invention relates to computing and can be used to interface the computing systems with the data communication backbone.

By bus No. 599,261 discloses a device for priority connection of information sources to a trunk, which contains in each channel a synchronization node, a trigger, a priority analysis node, a delay element, four diode elements for matching electrical signals, as well as prohibit and poll lines

The first input of the synchronization node through the first diode element matching the electrical signals is connected to the input of the prohibition device, the request input and the reset input of which are connected respectively to the second and third inputs of the synchronization node, the trigger output through the second and third diode elements of the electrical signal matching is connected respectively to the prohibition input and a polling output of a device which, via a barring diode element, is connected to a polling input connected via a fourth electric matching diode element cic signals with the first

the input of the priority analysis node, the second and third inputs of which are connected respectively to the vi; 1 trigger input and the output of the delay element, the input of the delay element connected to the trigger output, the inputs of which are connected. with the corresponding outputs of the synchronization unit connected with the fourth input with the first output of the priority analysis node, the second output of which is connected to the output of the exchange of the device.

The device accepts requests for triggers from sources of information (requests can arrive asynchronously). k: ak only one or several requests will be accepted, the prohibition line will be raised, and further requests will be stopped. At the same time, the priority analysis of the accepted triggers of the bid begins to be performed. As a result, all triggers reset the TC, except for one corresponding to the highest priority request. This analysis is implemented using the priority analysis nodes connected to the priority analysis block via the polling buses. After the time specified by the delay element, the priority analysis node is activated, corresponding to

request with the highest priority, and generates a signal to allow the exchange of this source of information. The delay element opens the priority analysis node only after the transient has cleared all low priority requests. After the Data Transfer session has ended, the source of information issues a reset signal to the appropriate trigger. The latter is reset, as a result of which the device is denied reception of the following requests by the device.

It is not excluded that a source that has just been served may, at the same time as a higher priority source, specify another request. It is also possible that the delay value may exceed the time of the transmission session. In such a case, the priority analysis node, which previously received the exchange enable signal, may issue a false exchange enable signal upon repeated request. This will happen because the corresponding delay element, due to its inertia, will still maintain a single signal at the control input of the corresponding output valve. Thus, before the request trigger is reset, the valve will have time to make a false signal that can lead to connecting this source to the trunk at the same time as the higher priority source, which is not permissible. All of this is a disadvantage, resulting in low reliability of the device.

The purpose of the invention is to increase the reliability of the device.

This goal is achieved by the fact that a threshold element is inserted into each channel of the device for priority connection of information sources to the bus, the input and output of which are connected respectively to the output of the channel delay element and to the input of the first diode element of the channel electric signals.

The block diagram of the device shown in the drawing.

The device contains diode elements 1-4 for matching electric signals, prohibition diode element 5, element NOT 6, element AND 7, triggers 8 and 9, element OR 10, elements 11 and 11; 12, HE elements 13 and 14, delay delay elements MeHTjilS, interdiction input 16, interrogation input 17, interrogation exit 18, interrogation input 19, reset input 20, exchange resolution output 21, synchronization node 22, priority analysis node 23, threshold element 24, channels 25-27, line 28 of the ban, line 29 of the survey.

The device works as follows.

When appearing at input 19, for example, channel 26 of a request signal from an information source, trigger 9 of channel 26 is switched to one state. If at the input 16 of the channel 26 the potential is zero, then the And element 7 of the channel 26 generates a signal that sets the trigger 8 of the channel 26 into one state. At the same time, a single signal appears through the input 16 of channel 26 and the output 18 of channel 26 on barring lines 28 and polling 29. If the interrogation signal at input 17 of channel 26. Is earlier than :: and the output of channel delay element 15 of channel 26, then triggers 8 and 9 of channel 26 are reset through elements 10, 11 and 13 of channel 26. This means that at the inputs The device is waiting for service at least one source with a higher priority.

If the demand signal at input 17 of channel 26 is more long than the output of element 15 of channel 26 delay, then output 21 of channel 26 through elements 12 and 13 of this channel transmits a signal allowing the source of information to connect to the trunk for data transmission. During the operation of the source in the line 28 of the prohibition using the trigger 8 of channel 26 and the diode element 2 of channel 26 there is a signal that blocks the connection of other sources. This signal due to the threshold element 24 of the channel 26 is valid until the output of the channel delay element 15 of the channel 26 does not have a logical zero signal. This will lead to the unlocking of the next request reception and to the temporary blocking of the exchange resolution signals using diode cells 4 and 5 of channel 26. A nepsection of the interrogation signal to the output 18 of channel 26 is carried out.

After completion of the operation, the source sends a signal to input 20, which resets the triggers 8 and 9 of the corresponding channel. After a time equal to the delay time of the element 15, the channel returns to its original state.

By connecting the output of the channel delay element 15, the channel threshold element 24 locks the next request reception until its corresponding delay element 15 returns to its original zero state. As a result, the possibility of the occurrence of false exchange resolution signals is excluded.

Thus, the invention increases the reliability of the operation of a known device for prioritizing the submission of information sources to a highway.

Claims (1)

1. USSR author's certificate 599261, cl. G 06 F 9/18, 1976 (prototype). 18 29 L IS II VG