Matrix keyboard scanning and coding circuit

Abstract

The invention discloses a matrix keyboard scanning and coding circuit. The circuit comprises a matrix keyboard, a first shift register, a second shift register, a status code register and a coder; according to the circuit, through control of a scanning pulse and a shift pulse which satisfy a specific time sequence demand, the single-key operations, combined key operations or maintained statuses of the matrix keyboard are converted into valid status codes and invalid status codes with the same binary length; after the codes are coded by the coder, a valid key number corresponding to each valid status code is output or invalid key numbers corresponding to all invalid status codes are output; different single-key operations, combined key operations or maintained statuses are only reflected in the differences of the status codes; if key operation functions need to be reduced or increased, or if the key operation functions need to be adjusted, the structure of the keyboard scanning circuit does not need to be modified; and only the coder needs to be modified according to the corresponding relationships between the increased or reduced status codes and the key numbers. According to the circuits disclosed by the invention, it is unnecessary to compile and operate programs; and the work is reliable.

Description

technical field [0001] The invention relates to a keyboard scanning circuit, in particular to a matrix keyboard scanning and coding circuit. Background technique [0002] With the continuous development of embedded technology, various electronic products generally use microcontrollers as the control core, and keyboards as the main input device, which have been widely used. [0003] The current keyboard scanning is mainly controlled by the microcontroller, which needs to be carried out by running the program in the microcontroller. When encountering interference, the program will run away, and the scanning program will not work normally. [0004] The invention patent with the application number CN201010153560.2 "A Quick Scanning and Positioning Method for a Matrix Keyboard" adopts the method of keyboard interrupt triggering to enter the scanning and positioning process of the keyboard, and uses the method of repeating the keyboard scanning steps several times to determine whe...

AI Technical Summary

Problems solved by technology

However, the single-key operation and the combined key operation of the method need to be processed separately; the keyboard operation function of effective operation is not performed after the keyboard state is maintained for a period of time; when increasing or decreasing the key operation function or adjusting the key operation function, it is necessary to modify the keyboard scan Locate program structure

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