SU1555852A1 - Sensor keyboard - Google Patents

Abstract

The invention relates to input and output devices, in particular to touch sensitive keyboards. The purpose of the invention — improving the reliability of the touch pad — is achieved by eliminating the influence of touch chatter and releasing the touch pad on the operation of the touch pad. The touch keyboard contains a pulse generator 1, two elements OR 2, 10, two counters 3, 4 pulses, a multiplexer 5, touch pads 6, a register 7, address 8 and information 9 outputs. When the touch pad 6 is touched and the code combinations coincide, the logic level "1" appears at the output of multiplexer 5. This signal permits operation of counter 4, the filling time of which is longer than the period of chatter. If the bounce continues, then the output of multiplexer 5 is a logic level "0", which allows counter 3 to operate, i.e. re-search the site code 6. At the end of contact bounce, the logic level "1" at the output of multiplexer 5 does not change until a logical "1" appears at the output of counter 4, corresponding to the end of detection of the code for the touch pad 6. When you release the touch pad 6, the bounce does not affect the operation of the touch keyboard, since the first logical level "0" at the output of multiplexer 5 brings the touch keyboard back to its original state when counter 4 is zero and counter 3 counts the generator pulses. 1 il.

Description

The invention relates to a pulse technique and can be used in input and output devices.

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

The drawing shows a touch keyboard.

The touch keyboard contains the generator 1, the first element OR 2, the first 3 and second counters, the multiplexer 5, the touch pads 6, the register 7, the address 8 and the information 9 outputs, as well as the second element OR 10.

The information inputs of the multiplexer 5 are connected to the corresponding sensor pads 6, and the control inputs to the corresponding outputs of the first counter 3 and the inputs of the register 7, the outputs of which are the address outputs 8 of the device, and the synchronization input connected to the output of the second counter k and the second input of the second element OR 10, the output of which is connected to the counting input of the first counter 3, and the first input with the output of the generator 1 and the first input of the first element —OR 2, the output of which is connected to the counting the input of the second counter, and the second input connected to the output of the second counter 4, which is the information output 9 of the device.

The keyboard works as follows.

In the initial state, when there is no contact with any of the sites, the output of multiplexer 5 is a logic level O,

0

0 5

five

which contains the second counter 4 in the zero state and allows the pulse of the generator 1 to pass through the second element OR 10 to the counting input of the first counter 3, sequentially polling the information inputs of the multiplexer. The information in the register 7 and at the address outputs 8 does not change, the information output 9 maintains the logic level O.

If the operator touches one of the touch pads 6, then the output of multiplexer 5 with the code combination of the first counter 3 corresponding to the number of the selected touch pad 6, provided that the touch bounce ends, a logical level 1 appears that will allow the counter to work, the fill time of which is selected maximum bounce period to determine a reliable touch. By the voltage drop at the output of multiplexer 5, the information from the address inputs of multiplexer 5 will be overwritten in register 7. The level of logical 1 at the output of multiplexer 5 will prevent the generator 1 from passing through the second element OR 10 by stopping the filling of the first counter 3. the counter will stop filling it, passing through the first element OR 2 to the counting input of the second counter, and also allow reading information from the address outputs of the register. If, at the moment when the touch pad 6 is located, the touch bounce has not finished yet, then the very first bounce pulse will be counted by the first counter 3, thus causing the search to be repeated

6 until the bounce is complete by the time the touch pad 6 is located.

When the touch pad 6 is released, the first logical level O will reset the keyboard to its original state.

Claims (1)

Invention Formula A touch keyboard containing a generator, the first OR element, the first and second counters, a multiplexer, the information inputs of which are connected to the corresponding touch pads, and the control inputs of the multiplexer are connected to the corresponding outputs of the first counter and 0 The register, the outputs of which are the address outputs of the keyboard, and the output of the second counter, is an information output of the keyboard, characterized in that, in order to increase reliability, a second OR element is entered, the generator output is connected to the first input of the first OR element and the input of the second OR element, the output of which is connected to the counting input of the first counter, the output of the second counter is connected to the second input of the first OR element, the output of which is connected to the counting input of the second counter, the reset input of which connected to the output of the multiplexer, the second input of the second OR gate and the input of the synchronization register.