SU1656517A1 - Data input device - Google Patents

Abstract

The invention relates to automation and computing and can be used in devices for entering information from the keyboard. The aim of the invention is to increase the reliability of the input information. The device contains a counter 1, a decoder 2, bpok 3 switching elements, an encoder 4, the element AND 5, the elements OR 6, 7, the trigger 8, the register 9, the block 10 load elements. The device allows you to eliminate the bounce of the contacts of the switching elements, as well as to exclude the possibility of reading false information when you press two or more keys simultaneously 1 sludge.

Description

The invention relates to automation and computing and can be used in keyboard input devices.

The purpose of the invention is to increase the reliability of the input information.

The drawing shows a block diagram of the device.

The device contains a counter 1, a decoder 2, a block 3 of switching elements, an encoder 4, an element AND 5, a first 6 and a second 7 elements OR, a trigger 8, a register 9, a block 10 of load elements on resistors 10, a device synchronization input 11, a control input 12 devices, synchronization output 13, information outputs 14 and 15 of the device.

The device works as follows.

At the synchronization input 11 of the device, clock pulses are received from the device into which information is entered. In the initial state at the second input

element 5 has a level 1, and the pulses arriving at its first input pass to the element OR 6 and to the input of counter 1. The code at the output of counter 1 changes with the arrival of the clock pulse and through the decoder 2 turns on one of the groups of block 3 alternately switching elements. In the initial state, all switching elements are open, at all inputs of the element OR 7 and register 9 there is level O. Register 9 and trigger 8 are in the reset state, therefore, at the inverse output of trigger 8 is level 1. which goes to the second input element and 5.

When one of the switching elements of unit 3 is closed, counter 1 continues counting clock pulses until the code at its output matches the code corresponding to the group of switching elements of unit 3 in accordance with the decoder state table 2. At that, level 1 from the decoder 2 output pass

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Dit through the closed switching element of the block 3 and goes to one of the inputs of the element OR 7 and to one of the information inputs of the register 9. From the output of the element OR 7, level 1 is fed to the input of the trigger setup 8 in 1, the key is pressed. From the inverse output of the trigger 8, the level O arrives at the second input of the element And 5. After that, the element 5 does not pass the clock pulses through the element OR 6 to the input of the counter 1, fixing the state of the last corresponding to the group in which the switching element is closed. At the same time, one of the triggers of register 9 is set. The signal from it is fed to the input of the encoder 4, and the code is set at the output of the latter. corresponding to the number of the closed switching element in the group.

The bounce of the contacts of the switching element when the key is pressed is eliminated by inserting trigger device 8 into the circuit.

After reading the information, the computer sends a signal to the input 12 of the device, which is set to O of the trigger 8 and register 9. This signal, having passed through the OR 6 element, transfers into the next state counter 1, due to which the bounce effect is set at pressing the key if the information is read by the computer from the counter until the switching element is opened.

The resistance value of the resistors is selected so that when two or more keys are pressed simultaneously, a sufficient change in the voltage level at the output of the switching elements of the switching elements 3 and the operation of the OR 7 element and the register 9 does not occur.

Claims (1)

Invention Formula A device for inputting information, comprising a counter, a decoder, an encoder, a block of switching elements, an element whose first input is a synchronization input of the device, the outputs of the counter are connected to the inputs of the decoder and are the first group of information outputs of the device, the outputs of the decoder are connected to the inputs of the switching block elements of the encoder outputs are the second group of information outputs of the device, characterized in that, in order to increase the reliability of the input information, pty and second elements OR, register, trigger, block of load elements on resistors, some of whose outputs are connected to the corresponding outputs of the block of switching elements, information inputs of the register, inputs of the second an OR element whose output is connected to a trigger setup input, the forward output of which is a device sync output, an AND element output connected to the first input of the first OR element whose output is connected to the counter input, the encoder inputs are connected to the register outputs, a reset input which is connected to the second input of the first element OR, the reset input of the trigger and is the control input of the device, the inverse output of the trigger is connected to the second input of the AND element, the other terminals of the resistors are connected to the zero bus about the potential.