SU1208548A1 - Information input device - Google Patents

Abstract

The device relates to the field of automation and computer technology and can be used in keyboard consoles of various systems and in information input devices. The purpose of the invention is to increase the reliability of the device. The purpose of the invention is achieved by introducing into the device a controlled multivibrator, a second, AND-NOT element and a register. The introduction of new elements protects the device from false positives: due to the bounce of the contacts of the switching elements of the keyboard. 1. il.

Description

one

The invention relates to automation and computing and can be used in keypads of various systems and in information input devices.

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

The drawing shows a block diagram of the device.

The device for entering information contains a matrix of 1 switching elements, the first element IS-NOT 2, switch 3, controlled multivibrator 4, triggers 5-7, the second element IS-HE 8, counter 9, element 10, register 11, decoder 12. At input 13, a signal is sent to enable polling, to input 14 - clock pulses. In addition, the device contains an output 15 End of the formation of the code and information outputs 16 and 7 "

The device for entering information works with a computer (or any other discrete initiating device. In the mode of request-response,

In the initial state, all the switching elements of the matrix 1 are closed and the outputs O and NOT 2 and switch 3 have a potential O, Potential O, coming from the output to the switch 3, time ™ decides the operation of the multivibrator 4, input 13 has a potential O, which sets a reset trigger on input 5 to the zero state, the output of which sets reset reset 6 on the input also to the zero state. The first pulse of the multivibrator 4 arriving at the trigger input of trigger 7, at. In the absence of a potential O on the information input, this trigger sets to the zero state. He himself allows 8 clocks to pass through the IS-NOT element to: and the input of counter 9 and to the synchronization inputs of triggers 5 and 6, Counter 9 successively changes its state positive fronts of clock pulses coming from the input 14, Potential 1, coming from the output of the element And 10 to the input of the register 11, allow the code combination from the output of the counter 9 to the input of the decoder 12 to pass through the register 1, With the arrival of the request to the input 13

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potential 1, the device maintains its state before the closure of the switching element of the matrix 1,

When the switching element is closed in one of the horizontal groups O from the output of the decoder 12, through this switching element, it enters the input of the AND-HE element 2, on whose exit it is set

10 arriving at the input of the trigger 5, which is on the negative front. the clock pulse is set to one. Logical zero with inverse output trigger 5

15 walks through AND 10 and enters the input of register 11, which in this case stores the binary code of counter 9, corresponding to this horizontal group of switching elements. Counter 9 continues to change its state until a code appears corresponding to a vertical group of switching elements, the closed contact of one of which causes the appearance at the output of the switch 3 1, which is written down the negative edge of the clock pulse to trigger 6. The inverse output of trigger 6 sets at the entrance

30 trigger 7 in one state. A logical zero from the inverted output of the trigger 7 prohibits the passage of 8 clock pulses through the NAND element arriving at the input of the counter ka 9 and to the inputs of the flip-flops 5 and 6, the logical unit from the output of the switch 3 prohibits the operation of the multivibrator 4. corresponding to the single state of flip-flop 6, indicates that the code generation is completed and at outputs 16 and 17 there is a binary code corresponding to the closed switching element of the matrix} 5 tsi 1 ". In response to this signal, an external device (for example, the computer reads AET information and then sets the potential at the input 1-3 O, which sets the flip-flops 5 and 6

5Q to zero and output 15

potential O is set. Regardless of the signal level at input 13, information at outputs 16 and 17 is stored until the switching element 55 is opened. In this case, the output of the switch 3 is set to 1, which enables the operation of the multivibrator 4. But the first 40

3

The pulse from the output of the multivibrator 4 sets the trigger 7 to the zero state at the input, and the device returns to the initial state.

The reliability of the proposed device is compromised by the fact that the counter and triggers change their state at different points in time, in particular, the counter changes its state along the positive front of the input clock pulses, and the first and second triggers - negative, and this does not allow apply special measures of protection against impulse pickups on the chains coming from the matrix.

The introduction of new elements, in particular, a controlled multivibrator, protects the device from spurious events due to the bounce of the contacts of the switching elements of the matrix. The protection is performed by setting the period of oscillation of the output pulses of the multivibrator to longer than the time of possible bounce of the contacts of the switching elements of the matrix.

Claims (1)

Invention Formula A device for entering information containing a matrix of switching elements, the first IS-NOT element, a multiplexer, three triggers, a counter, an AND element and a decoder, the outputs of which are connected to horizontal buses of the matrix of switching elements of which are connected to the information inputs of the multiplexer and the inputs of the first AND element NOT, counter outputs are connected to 08548 the multiplexer inputs and are the first informational: device outputs, the Reset input of the first trigger is an input 5 of the device polling, the inverse output of the first trigger is connected to the first input of the AND element, and the direct output is connected to the Reset input of the second trigger, the direct output of which is output by the output of the output of the formation of the device code, which is This is because, in order to increase reliability, a controlled multivibrator has been introduced into it, the second The tS NAND element and the register, whose information inputs are connected to the corresponding outputs of the counter, and the outputs are connected to the inputs of the decoder and are the second information 20 outputs of the device, the register strobe input is connected to the output of the element I, the output of the multiplexer is connected to the information input of the second trigger and the control input 25 controlled multivibra, the output of which is connected to the synchronization input of the third trigger, the setup and information inputs of which are connected respectively to 30 inverse and forward outputs of the second trigger, and the inverse output is connected to the second input of the AND element and the first input of the second AND-NOT element, the second input of which is the input 35 clock pulses of the device, and the output is connected to the counter input and the synchronization inputs of the first and second triggers, the information input of the first trigger is connected to the output of the first NAND element,