Stand-alone keyboard scanning circuit and coding circuit

• Main Authors: LING YUN, GUO YANJIE, TANG WENYAN, ZHOU WEILONG, ZENG HONGBING, YUAN CHUANLAI, WANG BING
• Format: Patent
• Language: Chinese; English
• Published: 15.06.2016
• Subjects: BASIC ELECTRONIC CIRCUITRY; CALCULATING; CODE CONVERSION IN GENERAL; CODING; COMPUTING; COUNTING; DECODING; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; PHYSICS

The invention relates to a stand-alone keyboard scanning circuit and a coding circuit. The stand-alone keyboard scanning circuit and the coding circuit are composed of a stand-alone keyboard, a first shifting register, a second shifting register, a state code register and a coder. The scanning circuit is controlled through scanning pulses, first shifting pulses and second shifting pulses meeting a specific timing sequence requirement, single-key operation, combined-key operation and a stand-alone keyboard maintaining state are scanned and transformed into valid state codes and invalid state codes, the valid state codes and the invalid state codes are equal in binary system length and are coded through the coder of the coding circuit, and then a valid key number corresponding to each valid state code or an invalid key number corresponding to all the invalid state codes is output; different kinds of single-key operation, combined-key operation and the stand-alone keyboard maintaining state are only reflected in