Input Device With a Keyboard in Which Actuation of a Key More Than Once May Cause a Different Function to Be Performed

1. Field of the Invention

This invention relates to an input device capable of introducing a plurality of function inputs into a data processor by operation of ordinary input keys.

2. Description of Prior Arts

In the input device for conventional computer systems where a plurality of functions are assigned to a single input key, double operations are required to select one function out of a plurality of functions with another key so as to introduce such one function input into the system, with the consequence that the number of key operations increases and the circuit construction becomes increasingly complicated.

It is an object of the present invention to provide an input device which solves the abovementioned defect inherent is the conventional input device, wherein a function is made selectively introducible by an input key assigned with a plurality of functions without the necessity for operating any special input means.

According to the present invention, generally, there is provided an input device for a data processor, comprising: a plurality of keys to instruct the input of functions into the data processor; a state memory which stores therein information on the processing state of the data processor; a memory which stores therein pieces of processing state information of the state memory, a plurality of functions to be called upon and instructed for input by the keys, and pieces of processing state information to be newly stored in the state memory; and control means which renders accessible the abovementioned memory based on the combination of the keys and the pieces of processing state information stored in the state memory, and produces as outputs each one of the function and the processing state information out of a plurality of such functions and pieces of processing state information, and stores new pieces of processing state information in the state memory.

The foregoing object, and other objects as well as the detailed construction and function of the input device according to the present invention will be more apparent from the following description of a preferred embodiment thereof when read in conjunction with the accompanying drawings.

FIG. 1 is a schematic block diagram showing one embodiment of the input device according to the present invention;

FIG. 2 is a diagram showing one example of a layout of the input keys;

FIG. 3 is an explanatory diagram of a function table; and

FIG. 4A and 4B are diagrams showing examples of the input keys.

FIG. 1 shows one embodiment of a computer provided with the input device according to the present invention, which is essentially constructed with a key input device KB having a plurality of input keys such as 16 input keys K1, K2, . . . K16 arranged in a manner as shown in FIG. 2; an operation unit ALU, which renders accessible a memory based on the input keys and pieces of processing state information stored in a state memory of an auxiliary memory to be described later, produces as outputs each one of the function and the processing state information out of the abovementioned plurality of functions and pieces of processing state information, and stores new pieces of processing state information in the auxiliary memory; the auxiliary memory RAM to maintain the state of ALU (i.e., a "status memory" for storing information as to the status of the apparatus herein described); and a read-only memory ROM which is coupled with the operation unit ALU and stores therein a function table, in which the functions to be carried out by the operation unit ALU have been assigned in advance on the basis of the input states of the input keys K1 to K16 on the key input device KB and the memory state of the auxiliary memory RAM.

The auxiliary memory RAM as herein used has a memory capacity of, for example, 4 bits, and maintains 16 modes (0 to 15) of the operation unit ALU. The read-only memory ROM contains therein a function table, in which the execution functions of the operation unit ALU, each being assigned to each of the total 256 kinds of input information to be determined by the 16 input keys K1 to K16 on the key input device KB and the 16 modes (0 to 15) which the auxiliary memory RAM maintains, have been written. One example of such a function table is illustrated in FIG. 3, wherein the functions to be carried out by the operation unit ALU and the states, to which the operation unit ALU is to be shifted after its execution of the designated function, are written in a ROM address to be determined by combination of the input key Ki (i=1 to 16) and each state x (x=0 to 15). For example, if it is assumed that the input key which has been depressed is "K1", for example, and the content of RAM at this time is "1", the state of ALU is "1". Therefore, for the ROM address to be determined by the combination of (K1, 1) the second position from the top of the function table in FIG. 3 is designated. Consequently, the operation unit ALU reads out the function (or "operational signal") b from the ROM function table to execute the same, and then reads out the state "9" corresponding to the function to write the value "9" in the auxiliary memory RAM. In other words, by the input of the key K1, the function b is carried out, and the state of ALU changes from "1" to "9".

In the following, explanations will be made as to the operation for carrying out the function in the operation unit ALU when two keys, e.g., the keys K5 and K9, on the key input device KB are depressed in a certain sequence. Here, the surfaces of the keys K5 and K9 are divided into the upper and lower portions as shown in FIGS. 4A and 4B, the key K5 having a symbol (") in its upper portion and a symbol (") in its lower portion, while the key K9 having a letter (A) in its upper portion and a word (PRINT) in its lower portion. In the operation unit ALU, when a certain function is to be selected from the content of RAM and the function table to ROM with respect to these key inputs, if the function as selected from the function table in FIG. 3 is a, the character in the upper portion of the key is generated, while the character in the lower portion of the key is generated, if the selected function is b.

Now assume that, when the content of RAM is "0", the above-mentioned keys K5 and K9 in the key input device KB are depressed in the sequence of K9, K5, K9, K9, K5. Then, the operation unit ALU performs the data processing as mentioned below.

(1) The initial key input (K9):

The address (K9, 0) on the function table is determined on the basis of the combination of the key K9 and the content of RAM of "0". Since the function in this address is b according to the example shown in FIG. 3, the operation unit ALU generates the word (PRINT) in the lower portion of the key K9. Subsequently, the shifting state "0" is read out of the function table, and the content "0" is stored in RAM.

(2) The second key input (K5):

Based on combination of the key K5 and the content of RAM of "0", the address (K5, 0) on the function table is determined, whereby the function a is selected as shown in FIG. 3, and the operation unit ALU carries out the function a to generate the character ("). Subsequently, the state "1" is read out of the function table and stored in RAM.

(3) The third key input (K9):

The ROM address (K9, 1) is determined in the manner as mentioned above, and the operation unit ALU carries out the function a to generate the character (A). The state "1" is then read out of the function table and stored in RAM.

(4) The fourth key input (K9):

In the same manner as in the abovementioned third key input, the ROM address (K9, 1) is selected, and the operation unit ALU carries out the same function to generate the character (A). The content of RAM remains "1".

(5) The fifth and last key input (K5):

The address (K5, 1) is determined by the key input K5, and the operation unit ALU carries out the function b to generate the symbol ("). Then, the state "0" is read out of the function table and stored in RAM.

In the manner as mentioned in the foregoing, the word (PRINT) and the letter (A) are generated by the sequential key input by the input keys K9, K5, K9, K9 and K5.

Incidentally, in the above-described embodiment, two functions are allotted to each key, although the present invention is not limited to this mode alone, but three or more functions may be assigned to each key and the contents of the function table can be prepared in advance in conformity to such functions.

Thus, according to the present invention, it is possible to perform multifunction input operations by the operation of ordinary input keys, so that complicacy in the key operation as well as intricacy in the circuit construction which have so far been considered a defect in this kind of input device, can be solved.