System for selecting a key by comparing the key code data of predetermined priority corresponding to key input flag of simultaneously pressed plurality of keys

• US 5,734,928 A
• Filed: 04/19/1995
• Issued: 03/31/1998
• Est. Priority Date: 04/19/1994
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Nakasuji, Masataka
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Chen, Anderson I.
• Application Number:
  US08/424,083
• Time in Patent Office: 1,077 Days
• Field of Search: 341/22, 341/23, 341/24, 341/26, 345/168, 364/709, 364/927.2, 364/928, 364/948.1
• US Class Current: 710/67
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes

Abstract

A CPU outputs a signal from an output port group, and receives an input signal from input port group, whereby a pressed key of input key group is detected. When there are a plurality of keys which are pressed, CPU selects a key with priority based on valid key information in a ROM, and stores code data of the selected key in a key code portion. Consequently, only one of the plurality of keys pressed simultaneously is selected as an input key.

Claims

1. A key input apparatus, comprising:

a keyboard provided with a plurality of keys;

key input detecting means for detecting a key which is pressed among said plurality of keys;

plural key input detecting means for detecting, based on a result of detection by said key input detecting means, pressing of at least two keys simultaneously among said plurality of keys;

key priority storing means for storing predetermined priority of each of said plurality of keys;

comparing means for comparing said predetermined priority of each of said at least two keys detected by said plural key input detecting means to generate a compared result; and

key selecting means for selecting one of said at least two keys as a pressed key based on said compared result;

said key input detecting means including

reading means for reading an output from each of said plurality of keys, and

data storing means for storing prescribed data in accordance with an output from said reading means, and

said plural key input detecting means refers to the data stored in said data storing means, for detecting plural data being stored;

wherein the data stored in said data storing means includes a key input flag indicative of a pressed key; and

said plural key input detecting means detects pressing of at least two keys of said plurality of keys, when a plurality of said key input flags are stored; and

wherein said comparing means includes

key code data reading means for reading key code data corresponding to said key input flag, and

key code data selecting means for successively comparing

said priority of the key code data read by said key code data reading means, and

said key selecting means selects key code data having highest priority.

2. A method for selecting a valid key input from a plurality of key inputs, comprising:

establishing priority data for each of a plurality of keys;

detecting which one of said plurality of keys has been pressed;

determining whether at least two keys have been pressed based on said detecting step;

comparing said priority data of each of said at least two keys to generate a compared result; and

selecting one of said at least two keys as a valid key based on said compared result,

wherein said detecting step includes,

reading an output from each of said plurality of keys,

storing prescribed data in accordance with said output read in said reading step, and

referring to the data stored in said storing step, for detecting plural data being stored,

wherein the data stored in said storing step includes a key input flag indicative of a pressed key, and

said determining step determines pressing of at least two keys of said plurality of keys, when a plurality of said key input flags are stored; and

wherein said comparing step includes

reading key code data corresponding to said key input flag, and

successively comparing said priority of the key code data read in said reading step, and

said selecting step selects key code data having highest priority.

3. A key input apparatus comprising:

a plurality of keys;

a key priority generating unit generating priority data for each of said plurality of keys;

a plural key input detecting unit detecting pressing of at least two of said plurality of keys simultaneously;

a comparing unit comparing said priority data of said at least two keys; and

a selecting unit selecting one of said at least two keys based on a comparison in said comparing unit,

wherein said plural key detecting unit includes,

a reading unit reading an output from each of said plurality of keys,

a data storing unit storing prescribed data in accordance with said output read by said reading unit, and

a referring unit referring to the data stored in said data storing unit, said referring unit detecting plural data being stored;

wherein the data stored in said data storing unit includes a key input flag indicative of a pressed key, and

said plural key input detecting unit detects pressing of at least two keys of said plurality of keys, when a plurality of said key input flags are stored, and

wherein said comparing unit includes

a key code data reading unit reading key code data corresponding to said key input flag, and

a key code data selecting unit successively comparing said priority of the key code data read by said key code data reading unit,

said key code data selecting unit selects key code data having highest priority.