SU1226627A1 - Device for eliminating contact chatter effects - Google Patents

Abstract

The invention relates to the field of automation and computing technology. And can be used in devices for keyboard input of information in a computer. The purpose of the invention is to increase reliably. The operation of the device is achieved by introducing into it the logical element (LE) NOT 7 and LE AND 6. In addition, the device contains contact 1, triggers 2 and 5, LZ OR-NOT 3, generator 4. At the output device high potential appears only after blocking the last contact bounce. In this case, the trigger 5 enters the logical state O only after the termination of the last bounce pulse. The operation of the device is explained in timing diagrams in the description of the invention. 2 Il. § (Л с: V с

Description

The invention relates to automation and computing technology and can be used in devices for keyboard input of information in a computer,

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

FIG. 1 is a diagram of an apparatus for eliminating the influence of contact bounce; in fig. 2 - time diagrams of his work.

The device contains a contact 1, the first trigger 2, the element R-CHI-NOT 3, the generator A, the second trigger 5, the elements AND 6 and NOT 7, and the contact 1 is connected to the information input of the first trigger 2 and the first input of the element OR-NOT 3 The output of which is connected to the input of the installation in O of the trigger 2, the clock input of which is connected to the output of the generator 4, and the output is connected to the information input of the trigger 5, the output of which is the output of the device. The output of the trigger 5 is connected to the second input of the element OR-NOT 3 and to the second input of the element 6 and the first vhched of which is connected to contact 1, and the output to the input of the installation in 1 of the trigger 2. The output of the generator 4 is connected through the element HE 7. with a trigger trigger input 5.

The device for eliminating contact bounce works as follows.

In the initial state, the information inputs of the flip-flops 2 and 5 and the output of the flip-flop 5 contain a logical O (FIG. 26, ..., g), the inputs of the installation into 1 and O of the flip-flop 2 are respectively the logical O and 1. The clock frequency from the generator 4. (Fig. 2 a) arrives. to the input of the trigger 2, blocked on the input of the installation in

 ABOUT

and through the element NOT 7 to the clock input of the trigger 5.

When contact 1 closes, a signal (logical 1) with bounce arrives at the information input of trigger 2 and through the OR-NOT 3 element on it. the input of the installation in O. Element I 6 is blocked by the output signal of the trigger 5, that is, the input to the installation in 1 of the trigger 2 is logical, the coincidence of the leading edge of the clock frequency with the level of logical 1 on the information input of the trigger 2 (Fig. 2 a, s) puts it in the logical 1 state (fig.

and 1 at this moment is logical. In the case of continuation of the bounce (26), since its inputs are set to O and 1

, t, -. I -

cues about ga trigger 2 through the element OR NOT 3

is reset to O (Fig. 25, B); Trigger 5 does not change its state, since the frequency of the clock pulses of the generator is selected less than the frequency of bounce. If at the next

r (the transition of trigger 2 to state 1 at the input of the installation in O does not appear for a time equal to half the period of the clock frequency, logical 1 arising from bounce

contact, the trigger 3 goes to state 1 (Fig. 2a, d), the OR-NOT 3 element is blocked, the Andb element is unblocked, the corresponding O inputs are set to the inputs O and 1 of the trigger-2

T

Thus, at the output of the device, a high potential appears only after the last bounce.

When the contact is opened at the information input and through the element 6, the input of the installation into 1 of the flip-flop 2 receives a logical O (Fig. 28) with a bounce on the area. If the leading edge of the clock frequency coincides with the level O of the input signal, trigger 2 goes to the zero state. However, the first bounce pulse returns trigger 2 to its original, i.e. single state (Fig. 2 &). Thus, the trigger 5 enters the state of logical O only after the end of the last bounce pulse. Further, the cycle of operation of the device is repeated.

Claims (1)

Invention Formula A device for eliminating the influence of contact bounce, containing a contact, a HH-NE, element, two triggers and a clock pulse generator, the first input of the OR element NOT connected to the contact and to the information input of a nepiaoro trigger, and the output to the installation input on the first the trigger, the clock of which is connected to the output of the clock pulse generator, and the output to the information input of the second trigger, characterized in that, in order to increase the reliability of operation, the element is NOT and the element AND whose first input is connected to the infor with the input of the first trigger, the output is with the installation input of 1 of this trigger, and the second input is with the second 12,66627 The input input of the element is OR NOT and with the direct output of the second trigger, the clock input of which is NOT connected to the output of the generator of clock pulses through the element. Ф1Аг.2. Editor N. Rogulich Order 2146/57 Circulation 816 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5  1LUL .-. JJ-- | L-r-T - r -1--.- --.- - - - Production and printing company, Uzhgorod, st. Project, 4 Compiled by M. Tsygankov Tehred V. Kadar Proofreader G. Reshetnik