SU1661978A1 - Device for protection against contact bounce - Google Patents

Abstract

The invention relates to a pulse technique and can be used in devices for forming, issuing and processing information in computing and telephony when developing devices with push-button testics. The aim of the invention is to increase the reliability and enhance the functionality of the device by generating an additional signal containing information on two features of the input command, namely, its supply and removal. The device contains the first 1, second 2 and third 3 elements OR - NOT, two (4 and 5) one-shot with restart, input bus 6 and output tires 7 - 10. Moreover, on bus 7, a signal is generated, which characterizes the bounce on the falling front of the input command , on bus 9 - on the front, and on tires 8 and 10 - respectively, the output bezbezgovy signal and signals that characterize both the front and rear edges of the input signal.

Description

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The invention relates to a pulse technique and can be used in devices for forming, issuing and processing information in computing and telephony when developing devices with push-button testics.

The purpose of the invention is to increase the reliability and enhance the functionality of the device by generating an additional signal containing information about two analyzed features of the input command, namely, its supply and removal.

Figure 1 shows an electrical functional diagram of the device; 2 shows timing diagrams for the operation of the device.

The device for protection against chattering of contacts contains the first 1, second 2 and third 3 elements OR NOT, the first 4 and second 5 one-shot with restart, input bus 6, output tires 8 - 10. Moreover, the first input of the element OR NOT

1 is connected to the input bus 6 and the input of the one-shot 5, the inverse output of which is connected to the output bus 10 and through the element OR-NOT 3 with the output bus 7 and the second input of the element OR-NOT 1, the output connected through the element OR-NOT

2k output bus 8, and through the one-shot 4 - to the bus 9 and the second inputs of the elements OR NOT 2 and 3.

The device works as follows.

In the initial state, the contacts of the switch (not shown) are open. In this case, bus 6 has a level 1 (Fig. 2a), buses 7 and 9 have levels O (Fig. 2 c and e), at the output of the element OR NOT 1 - level O (fig. 2 g), and at the output of the element OR-NOT 2 and tires 8 and 10 - level 1 (fig.2e).

At the moment the command is given on bus 6, the O level is set. At the same time, at the output of the OR-NOT 1 element, the signal level changes from O to 1, and at the output of the OR-NOT 2 element and output bus 8, from 1 to O, which corresponds to the front the front of the pulse generated on the bus 8. Under the action of a positive voltage drop formed at the output of the element OR NONE 1, a one-shot 4 is started, which generates a pulse with a duration longer than the period of the bounce pulses on the bus 6. This pulse is released by bus 9, as well as doing t to the second inputs of the elements OR-NOT 2 and 3, carried out their reliable blocking for the duration of its duration. The bounce pulses generated on the input bus 6 at the moment of issuing the command are inverted by the OR-NOT 1 element and fed to the first input of the OR-NOT 2 element and the one-shot 4 input, sequentially making its nauseous starts, which excludes the effect of contact bounce on the signal, selecting on bus 8. In addition, the bounce pulses on bus 6, under the action of growing edges, sequentially initiate and restart one-shot 5, which forms this at its inverse output, i.e. 5 output bus 10 (FIG. 26), a negative impulse arriving at the first input of an element OR NONE 3. Since the time parameters of the driver circuits of the single vibrators 4 and 5 are the same, and it is also assumed that these single vibrators are started as part of the device on different fronts of the original signal, the pulse produced by the one-vibrator 5 when an input command is given is always in time 5 lies inside the pulse generated by the single-oscillator 4, which eliminates the possibility of changing the state of the signal at the output of the element OR-HE 3 and the output 7, After the contact bounce stops, level O is established on bus 6, the output of the OR-NOT 1 element is level 1, and at the outputs of the elements LINE 2 and 3 and tires 8 and 7 the levels A. On the trailing edge of a 5 pulse generated by a one-shot. 4, the level O is set on the bus 9. At the time of the removal of the input command on the bus 6, the level 1 is set. At the same time, the output voltage OR-NOT 1 generates a voltage drop from 1 to O, and the output element OR-NOT 2 and the output bus 8 is from O to 1, which corresponds to the falling edge of the pulse generated on the bus 8. Under the action of the positive 5 voltage drop formed on the bus 6, the one-shot starts up, which on the output bus 10 and, therefore, the input element OR NOT 3 forms a negative impulse with a duration of 0 It increases the period of the following pulses of doebezg on the she-6. Since, as a result, O levels are acting on both inputs of the OR-NO 3 element, a level of 5 is set at its inputs, which goes to the bus 7 and simultaneously blocks its the duration of the element is OR NOT 1 by its in, its input. The bounce pulses generated by bus 6 when the input command is removed arrive at the first input element of the OR-NOT 1 and input of the one-shot 5, sequentially making its repeated starts. As a result, level 7 continues to act on bus 7, which eliminates the influence of bounce pulses on tires 8 and 9 at which levels 1 and O act, respectively. After contact bounce stops, level b is set on bus b On the falling edge of the pulse generated by the apparatus 5, level O is set on bus 7, level 1 on bus 10, and the device returns to its original state.

Thus, as a result of the cycle of operation of the device on the bus 8, a pulse is formed with a duration equal to the time interval between the moments of submission and removal of the input command to be executed. On tires 9 and 7, pulses are generated, the leading fronts of which coincide with the times of the same command feed and remove, and on the output bus 10, pulses containing information about both the feed and the removal of the input command.

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Formula of invention

A device for protection against chatter of contacts, containing the first element OR — NOT, the first and second inputs of which are connected respectively to the input and first output buses of the device, the second element OR — NOT, the first input of which is directly, and the second through the first one-shot, combined with the output the first element OR-NOT, the second one-shot and the second and third output tires, combined respectively with the output of the second element OR-NOT and the output of the first one-shot, characterized in that, in order to increase reliability and the device’s functionality, a third OR-NOT element and a fourth output bus combined with the inverse output of the second one-vibrator connected to the input bus and the first input of the third OR-NOT element, the second input of which is connected to the output of the first single-vibrator and the output combined with the first output bus device

Claims (1)

Claim A device for protection against contact bounce, containing the first element OR5 NOT, the first and second inputs of which are connected respectively to the input and first output buses of the device, the second element OR-NOT, the first input of which is direct, and the second through the first 10 one-shot, combined with the output the first OR-NOT element, the second one-shot and the second and third output buses, combined with the output of the second OR-NOT element and the output of the first one-shot, respectively, characterized in that. in order to increase the reliability and expand the functional capabilities of the device, the third OR-NOT element and the fourth output bus are combined into it, combined with the inverse output of the second one-shot connected to the input bus input and the first input of the third OR-NOT element, the second input of which is connected to the output of the first one-shot 25 ra, and the output is combined with the first output bus of the device.