JP4906178B2 - keyboard - Google Patents

Description

例えば、図７のようなメモリマップでは、コラム２が「２４ｈ」、コラム３が「Ｄ０ｈ」であり、これら各コラムは２キー以上の押下があるものと判定される。
上述の方法で、ステップ５０３で２キー以上のＯＮキーが存在するラインが存在しないと判定された場合は回り込み現象はないということであり、キーが確定され、確定スキャンメモリに記憶される。
【００３９】
また、ステップ５０３で２キー以上のＯＮキーが存在するラインが少なくとも１つ存在すると判定された場合はステップ５０４へ進む。
次に、ステップ５０４において、ロウ側の各ラインのキーのＯＮ数をカウントし、２キー以上のＯＮキーが存在するラインが少なくとも１つ存在するか否かを判定する。
【００４０】
図８は、本実施例によるロウ側のラインのカウントを説明する図である。この図は、図７と同様に一時スキャンメモリのメモリマップの一例を示しており、「１」はキーのＯＮ状態、「０」はキーのＯＦＦ状態をそれぞれ表す。図７同様、各ロウと各コラムは入れ替えて対角表示している。
本実施例では、各ロウ毎にカウンタを用いてデータを足し込み、カウンタの値が２以上であるか否かで２キー以上の押下を検出する。例えば図８においてはロウ２のカウンタの値は２であるので、ロウ２は２キー以上の押下があると判定される。
【００４１】
上述の方法で、ステップ５０４で２キー以上のＯＮキーが存在するラインが存在しないと判定された場合は回り込みはないということであり、キーが確定され、確定スキャンメモリに記憶される。
また、ステップ５０４で２キー以上のＯＮキーが存在するラインが少なくとも１つ存在すると判定された場合はステップ５０５へ進む。
【００４２】
ステップ５０５では新規に押下されたキーによるＯＮ状態の検出が同時に２個以上あったかどうかをチェックする。図５を参照して既に説明したように、ロウ側に２キー以上のＯＮキーが存在するラインが少なくとも１つ存在していても、必ずしも回り込みが発生しているとは限らない。正常なキー操作では、キーは１つずつ順次押下されるので、一時スキャンメモリにはキーのＯＮを示す「１」が１つずつ現れるが、キーの多重打鍵の場合は一時スキャンメモリにはキーのＯＮを示す「１」が同時に２以上現れることになる。従って、ステップ５０５において新規に押下されたキーによるＯＮ状態の検出が同時に２個以上あったかどうかを検査することでこのような誤認識を防ぎ、回り込み現象の有無の判定をより確実なものにする。
【００４３】
図９は、本実施例による新規に押下されるキー数のカウントを説明する図である。この図は、図７又は８と同様に一時スキャンメモリのメモリマップの一例を示しており、「１」はキーのＯＮ状態、「０」はキーのＯＦＦ状態をそれぞれ表す。図７及び８同様、各ロウと各コラムは入れ替えて対角表示している。
本実施例では、上述のようにキーボードのスキャンの結果はメモリマップ形式で一時スキャンメモリに一時的に記憶されている。ステップ５０５では、これを確定スキャンメモリと比較し、差分をとることで図９に示す変化ビットとして抽出する。ロウ側のラインのビット値が００ｈではないようなラインが２つ以上で存在すれば、キーが同時に２以上押下されたということになる。
【００４４】
上述の方法で、ステップ５０５で同時に２個以上はないと判定された場合は、回り込みはないということなのでキーが確定され、確定スキャンメモリに記憶される。
また、ステップ５０５で同時に２個以上あったと判定された場合は場合は、回り込み現象が発生したということになる。
【００４５】
このように、本発明の第２の実施例によれば、例えば点字入力を行う場合などのような、６キーあるいは８キーといったような、複数キーの正常なキー入力が可能なキーボードに対しても回り込み検査を実現することができる。
【００４６】
【発明の効果】
以上説明したように、第１の発明によれば、回り込み検査のためのＦキーロールオーバー技術を、１回のキースキャン内に実現するので、高速なキースキャン処理を実行でき、また、第三者によるキースキャンの解析を困難にすることが可能であり、安全性が高まる。
【００４７】
第２の発明によれば、例えば点字入力を行う場合などのような、６キーあるいは８キーといったような、複数キーの正常なキー入力が可能なキーボードに対しても回り込み検査を実現することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例によるキーボード制御ファームウェアの概略図である。
【図２】本発明の第１の実施例によるフローチャートを示す図である。
【図３】「Ａ」キーが押下された場合を説明する図である。
【図４】「Ｂ」、「Ｃ」、「Ｄ」キーが同時に押下された場合を説明する図である。
【図５】複数のキーが押下された場合の一時スキャンメモリのメモリマップを例示する図である。
【図６】本発明の第２の実施例によるフローチャートを示す図である。
【図７】本実施例によるコラム側のラインのカウントを説明する図である。
【図８】本実施例によるロウ側のラインのカウントを説明する図である。
【図９】本実施例による新規に押下されるキー数のカウントを説明する図である。
【符号の説明】
１…キーボード制御ファームウェア
１０１…キーバッファ
１０２…確定スキャンメモリ
１０３…第１のカウンタ
１０４…第２のカウンタ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scan type keyboard in which a plurality of key switches are arranged in a matrix.
[0002]
[Prior art]
In recent years, keyboards used in personal computers and the like have been required to have a higher speed of key scan processing as applications become more multifunctional and communication speeded up.
In a scan-type keyboard in which a plurality of key switches are arranged in a matrix, generally, the membrane switch key matrix has 8 lines on the column side and 16 to 18 lines on the row side. In such a key matrix, key scanning is performed by sequentially setting the row line on the low side to the low level and reading the eight column side states corresponding to the row side.
[0003]
In such a keyboard, when a plurality of key switches are pressed at the same time, a signal wraps around and a pseudo input state is entered as if another key other than the pressed key is operated. In order to avoid such a wraparound phenomenon, various solutions have been conventionally used by using keyboard control firmware.
One of them is the method using the F key rollover technique. This is the key already pressed When This is a method for determining that a wraparound has occurred when the total number of pressed keys including the newly pressed key is 4 or more and the newly pressed key is 2 or more.
[0004]
[Problems to be solved by the invention]
In the conventional method using the F-key rollover technique for the wraparound determination, first, a key scan is performed for each key to check whether or not the key is pressed. The key scan is executed again from the pressed key, and after checking the pressed state of other keys, it is determined whether or not the key can be input. For this reason, there is a problem that the time required for the key scan becomes longer. In addition, there is a problem in that an output by pressing a key is easily analyzed by a third party by inputting an external signal by analyzing the timing of key scanning. Further, in the method using the F-key rollover technique, when four or more keys are pressed, it is always determined that a wraparound has occurred. For example, when a braille input is performed with a keyboard, 6 It cannot respond to normal key input that combines keys or 8 keys at the same time.
[0005]
Accordingly, a first object of the present invention is to realize a higher-speed key scan in a key scan method for performing a wraparound inspection using the F key rollover technique in view of the above problems.
In view of the above problems, a second object of the present invention is to provide a key scanning method capable of performing a loop check corresponding to a plurality of key inputs that can be input as normal key operations.
[0006]
[Means for Solving the Problems]
In order to achieve the first object, according to the first invention, the detection means for scanning the keys one by one to detect the newly pressed key, and the newly pressed key is a normal key. A key memory for temporarily storing the address of a newly pressed key and a key memory for temporarily storing the address of the newly pressed key when it is determined that the input is confirmed. The address is stored in the key buffer, which is stored only when the address is not yet stored in the key buffer, and when the address of the newly pressed key is already stored in the key buffer. If the sum of the number of addresses and the number of confirmed keys stored in the confirmed memory is 4 or more and the number of addresses stored in the key buffer is 2 or more, there is a wraparound And a flag for requesting transmission of a code with respect to the confirmation key and storing the newly pressed key as a confirmation key when it is determined that there is no wraparound. Key determining means for setting and moving to the next key scan.
[0007]
In order to achieve the second object, according to the second invention, there is provided a scan memory for temporarily storing a result of key scanning of a computer keyboard in a memory map format corresponding to one bit per key; In the confirmed memory for storing the confirmed key input in a memory map format corresponding to 1 bit per key, and in the memory map stored in the scan memory, at least one line on which two or more ON keys exist is on the low side. In the memory map stored in the scan memory, it is determined whether or not there is at least one line on the column side where two or more ON keys exist. Both the column side determination means, the row side determination means and the column side determination means have at least a line on which two or more ON keys exist. One when it is determined to be present, and a wraparound and determining key determination means.
[0008]
According to the first invention, since the F key rollover technique for the loop inspection is realized in one key scan, a high-speed key scan process can be executed, and a key scan analysis by a third party can be performed. Can be difficult.
According to the second aspect of the present invention, it is possible to realize a wraparound inspection even for a keyboard capable of normal key input of a plurality of keys, such as 6 keys or 8 keys, for example, when performing braille input.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to the key scanning method of the first embodiment of the present invention, the presence or absence of key depression is checked for each scanned key, and a wraparound inspection is performed as necessary.
FIG. 1 is a schematic diagram of keyboard control firmware according to a first embodiment of the present invention.
[0010]
The keyboard control firmware 1 according to the present embodiment is determined in a memory buffer format in which a key buffer 101 that stores the address of a newly pressed key as 1 byte per key for 4 keys and a key corresponding to 1 bit. A fixed scan memory 102 that stores the key input, a first counter 103 that counts the number of addresses stored in the key buffer 101, and the number of "1" that represents the fixed key in the fixed scan memory 102. And a second counter 104 that counts.
[0011]
FIG. 2 is a flowchart illustrating the first embodiment of the present invention.
First, the keyboard control firmware 1 checks whether or not it is time to perform key scanning in step 200, and executes key scanning in and after step 201 when it is time to perform key scanning. In general, chattering is likely to occur at the key contact until 8 to 10 ms after the key is pressed. In order to avoid this chattering, the key scan is executed every 8 to 10 ms in this embodiment. In other words, in this embodiment, the timing is set so that the key scan start cycle is 8 to 10 ms in step 200. The time required for the key scan processing itself after step 201 is shorter than this.
[0012]
The key scan is started by performing a scan initialization process (step 201) such as initialization of the scan port and clearing of the counters 103 and 104. Thereafter, by the processing from step 202 onward, each key is scanned, the presence / absence of key depression is checked, and a wraparound inspection is performed as necessary.
In step 202, it is determined whether there is a change in the key state. If there is no change in the state of the key, the process proceeds to step 208 and the scan is set for the next key.
[0013]
If it is determined in step 202 that the key state has changed, the process proceeds to step 203. There are two types of changes in the state of the key: a change from OFF to ON when the key is pressed, and a change from ON to OFF when the finger is released from the key. , It is determined which is the case.
If it is determined in step 203 that the key state has changed from ON to OFF, it means that the finger has been released from the key. In other words, the pressing of the key is completed, the wraparound inspection described later is completed, and the key is confirmed, so that the process proceeds to step 204, and the key-off process is performed.
[0014]
In step 204, the confirmed scan memory 102 is cleared and a data transmission flag is set. That is, since it is determined in step 203 that the key state has changed from ON to OFF, in step 204, an OFF code indicating the key OFF is set as a data transmission flag. Thereafter, the process proceeds to step 208, where the scan is set for the next key.
[0015]
If it is determined in step 203 that the key state has changed from OFF to ON, this means that the key has been newly pressed, and the process proceeds to step 205.
In step 205, the address of the newly pressed key is compared with the address of the unconfirmed key already stored in the key buffer 101, and it is determined whether or not there is a match. The key buffer 101 temporarily stores an address of a newly pressed key as an unconfirmed key address for detection of wraparound described later. The key buffer is present in the microcomputer, but its capacity is preferably as compact as possible due to restrictions on the hardware of the microcomputer. The key buffer 101 in this embodiment has a capacity of 4 bytes, which is the minimum necessary for detecting the wraparound, with the key address being 1 byte per key, but may have a capacity larger than that.
[0016]
If it is determined in step 205 that the address of the newly pressed key does not match the address of the unconfirmed key already stored in the key buffer 101, the process proceeds to step 206, where it is determined that they match. If yes, go to Step 210.
In step 206, the first counter 103 counts the number of addresses stored in the key buffer 101, and determines whether or not it is full.
[0017]
If it is determined in step 206 that the key buffer 101 is full, it means that the total number of keys is already 4 or more, which means that a wraparound phenomenon has occurred, so the key is not confirmed. Then, go to Step 208.
If it is determined in step 206 that the key buffer 101 is not full, the process proceeds to step 207.
[0018]
In step 207, the address of the newly pressed key is stored in the key buffer 101 as the address of the unconfirmed key. Then, the process proceeds to step 208, where the scan is set for the next key.
In step 210, a roundabout inspection is performed. In this wraparound check, first, the second counter 104 counts the number of new keys including other newly pressed keys (including unconfirmed keys) and the keys that have already been confirmed and stored in the confirmed scan memory 102. The number is counted as the total number of pressed keys. Then, it is determined whether or not the total number of pressed keys is 4 or more and the number of newly pressed keys is 2 or more.
[0019]
Here, the wraparound phenomenon will be described. In a scan-type keyboard in which a plurality of key switches are arranged in a matrix, for example, the membrane switch key matrix has 8 lines on the column side and 16 to 18 lines on the row side. Each line on the column side is connected to a 5V power source via a resistor. In the key scan in such a key matrix, when the low level is detected by sequentially setting the row line on the low side to the low level (0V), reading the eight column side states corresponding to the low side. It is determined that the key has been pressed.
[0020]
FIG. 3 is a diagram illustrating a case where the “A” key is pressed, and FIG. 4 is a diagram illustrating a case where the “B”, “C”, and “D” keys are pressed simultaneously.
In order to facilitate understanding of the wraparound phenomenon, in FIGS. 3 and 4, it is assumed that there are two column-side lines and two row-side lines, and the column-side lines as detection lines are X1 and X2, and the detection lines. Let Y1 and Y2 be the low-side lines that intersect with.
[0021]
The column side lines X1 and X2 are connected to a 5V power supply through resistors. Normally, the keyboard scan sequentially sets the low side lines to the low level (0V) and sets the voltage levels of the column side lines X1 and X2 to the low level. A key scan is made by looking.
FIG. 3 shows a case where the normal “A” key is normally pressed. When Y1 is set to a low level and viewed as the voltage level of X1, it is 0 V, so it is detected that the “A” key has been pressed.
[0022]
On the other hand, in FIG. 4, when Y1 is set to the low level, the current flows to the ground through the switches in the order of “C”, “D”, and “B”. At this time, since the voltage level of X1 is 0 V, it is erroneously detected that the “A” key is pressed.
This is a wraparound phenomenon.
Therefore, as described above, as the sneak condition for detecting the sneak phenomenon, the number of new keys including other newly pressed keys (including unconfirmed keys) is already confirmed and stored in the confirmed scan memory 102. The number of keys pressed is counted as the total number of pressed keys, and it is determined whether or not the total number of pressed keys is 4 or more and the number of newly pressed keys is 2 or more.
[0023]
If it is determined in step 210 that the above wraparound condition is met, the newly pressed key may have been generated by the wraparound, so the key is not confirmed. At this time, for example, a code “FF” may be output, and when the host receives the code, an alarm may be sounded to alert the user. Thereafter, the process proceeds to step 208, where the scan is set for the next key.
[0024]
If it is determined in step 210 that the above wraparound condition is not met, no wraparound phenomenon has occurred, and the process proceeds to step 211 in order to confirm the newly pressed key as a key input.
In step 211, the contents of the key buffer 101 are cleared, the newly pressed key is stored in the fixed scan memory 102 in the memory map format as the fixed key, and an ON code indicating key ON is set as a data transmission flag. Thereafter, the process proceeds to step 208, where the scan is set for the next key.
[0025]
In step 208, setting of the MCU port, setting of the address to be scanned next, and the like are executed.
In step 209, it is determined whether or not it is a scan end, that is, whether or not all keys on the keyboard have been scanned.
If it is determined in step 209 that the scan end has not been reached, there is a key that has not been scanned yet, so the process returns to step 202.
[0026]
If it is determined in step 209 that the scan has ended, all keys have been scanned, and the process proceeds to step 212.
For example, during one key scan cycle, it is determined that there is a key change in step 202, it is determined that the key change is from OFF to ON in step 203, and it does not match the address stored in the key buffer 101 in step 205. When the process of determining in step 206 that the key buffer 101 is not full is passed four times, four key addresses are stored in the key buffer 101, and a wraparound phenomenon occurs. Means that.
[0027]
In step 212, it is determined whether the data transmission flag is set. The determined key data is stored in the transmission buffer for transmitting the key data. When the transmission flag is set, the data is output from the transmission buffer. As described above, the data transmission flag is set in step 204 or step 211. That is, the data transmission flag is set in step 204 because the key change is from ON to OFF, and the data transmission flag is set in step 211 because it is determined that there is no wraparound by the wraparound inspection in step 210. This is because the newly pressed key is the confirmation key.
[0028]
If it is determined in step 212 that the data transmission flag is set, the corresponding key code is output, and the process returns to step 200.
If it is determined in step 212 that the data transmission flag is not set, it means that no operation is performed on the keyboard, and the process returns to step 200.
[0029]
As described above, in this embodiment, in step 200, the timing is taken so that the key scan cycle becomes a predetermined time, for example, 8 to 10 ms, and the next key scan is started. Further, according to the present embodiment, since the key scan is executed every predetermined time, only the address is stored or deleted in the key buffer 101 even if the key state is changed. There is almost no difference in the ON / OFF processing time, and the key scan can always be executed in a substantially constant time. As a result, it is possible to make it difficult to analyze key scans by a third party, and a highly reliable keyboard can be realized.
[0030]
As described above, according to the present embodiment, the F key rollover technique for the wraparound inspection is executed within one key scan, so that high-speed key scan processing is possible.
Next, a key scanning method according to the second embodiment of the present invention will be described.
In this embodiment, the key matrix includes 8 lines on the column side and 10 to 18 lines on the row side, and the state of each line on the column side is temporarily changed for each scan of the row side line. Temporary scan memory is provided for automatic recording.
[0031]
As described in the first embodiment, the keyboard scan is performed by setting the low-side lines one by one to the low level (or high level), and the column-side eight lines corresponding to the low side. This is done by reading the state of. In the present embodiment, the state of each read key is temporarily stored in a temporary scan memory. Temporary scan memory is stored in a memory map format in which one key is stored per bit. The column side has 8 bits and the row side has the number of lines (for example, 10 to 18 bits) corresponding to the key matrix. Is done.
[0032]
FIG. 5 is a diagram illustrating a memory map of the temporary scan memory when a plurality of keys are pressed. In this figure, the state in which the key is ON is indicated by “1”.
When a key wraparound phenomenon occurs when a plurality of keys are pressed, the ON state of the keys appears at the grid positions on the column side and the row side, as shown in FIG. 5A. That is, in any one line on the column side and any one line on the row side, the ON state of two or more keys occurs simultaneously.
[0033]
FIG. 5B is also a diagram exemplifying a case where two or more ON states occur in any one line on the column side and any one line on the row side. In this case, the key is turned on. The state does not appear at the lattice positions on the column side and the row side, and therefore, no wraparound phenomenon occurs. Actually, in normal key operation, the keys are sequentially pressed one by one. Therefore, in the matrix pattern shown in FIG. 5B, “1” indicating ON of the keys appears one by one.
[0034]
As described above, in both (a) and (b) of FIG. 5, the ON state of two or more keys is detected in any one line on the column side and any one line on the row side. The difference is how many ON keys are detected simultaneously when a new key is pressed.
Accordingly, in the second embodiment according to the present invention, first, the number of ONs of the keys of the respective lines on the column side and the respective lines on the row side is counted, and at least one line is counted in each of the column side line and the row side line. Count whether there are two or more ON keys. If there are two or more ON keys on one line, it is further counted whether or not there are two or more ON state detections by the newly pressed key. Is determined to have occurred.
[0035]
FIG. 6 is a flowchart according to the second embodiment of the present invention.
First, the keyboard firmware checks whether it is time to scan, and starts scanning when it is time to scan. First, in step 501, the scan port is initialized.
Subsequently, in step 502, a key scan is executed. The row side lines are set to the low level (or high level) one by one, and the states of the eight column side lines corresponding to the row side are read and stored in the temporary scan memory. In this temporary scan memory, it is stored in a memory map format in which one key is stored per bit. The column side is 8 bits and the row side is the number of lines (for example, 10 to 18 bits) corresponding to the key matrix. Only prepared.
[0036]
Next, in step 503, the number of ON keys of each line on the column side is counted, and it is determined whether or not there is at least one line having two or more ON keys.
FIG. 7 is a diagram for explaining the counting of lines on the column side according to the present embodiment. This figure shows an example of a memory map of the temporary scan memory, where “1” represents the key ON state and “0” represents the key OFF state. For simplicity, each row is called row 1, row 2, row 3,..., Row 8, each column is called column 1, column 2, column 3,. Each column is swapped and displayed diagonally.
[0037]
As described above, the ON / OFF state of each key is stored in the temporary scan memory in a memory map format, and the 8 lines in each column of the key matrix correspond to the 8 bits of each column in the temporary scan memory. Yes.
Table 1 shows the case where one or zero key is ON in each column of 8 bits, and each of them is displayed as a hexadecimal number such as “** h”. In step 503, based on Table 1, pressing of two or more keys is detected for each column stored in the temporary scan memory. That is, in step 503, when the key status of each column stored in the temporary scan memory does not apply to any of 00h, 01h, 02h, 04h, 08h, 10h, 20h, 40h, and 80h, 2 keys are used. It is determined that the above has been pressed.
[0038]
[Table 1]

For example, in the memory map as shown in FIG. 7, column 2 is “24h” and column 3 is “D0h”, and it is determined that each column has two or more key presses.
If it is determined in the above-described method that there is no line in which two or more ON keys exist in step 503, there is no wraparound phenomenon, and the key is determined and stored in the determined scan memory.
[0039]
If it is determined in step 503 that there is at least one line having two or more ON keys, the process proceeds to step 504.
Next, in step 504, the number of ONs of the keys on each row line is counted, and it is determined whether or not there is at least one line having two or more ON keys.
[0040]
FIG. 8 is a diagram for explaining the counting of the line on the row side according to the present embodiment. This figure shows an example of the memory map of the temporary scan memory as in FIG. 7, where “1” represents the key ON state and “0” represents the key OFF state. As in FIG. 7, each row and each column are interchanged and displayed diagonally.
In this embodiment, data is added using a counter for each row, and pressing of two or more keys is detected depending on whether the value of the counter is two or more. For example, in FIG. 8, the value of the counter of row 2 is 2, so that it is determined that row 2 has been pressed more than 2 keys.
[0041]
In the above-described method, if it is determined in step 504 that there is no line in which two or more ON keys exist, there is no wraparound, and the key is determined and stored in the determined scan memory.
If it is determined in step 504 that there is at least one line having two or more ON keys, the process proceeds to step 505.
[0042]
In step 505, it is checked whether or not two or more ON-states are detected at the same time by a newly pressed key. As already described with reference to FIG. 5, even if there is at least one line having two or more ON keys on the low side, the wraparound does not necessarily occur. In normal key operation, the keys are sequentially pressed one by one, so “1” indicating ON of the key appears one by one in the temporary scan memory. Two or more “1” s indicating ON of the same will appear at the same time. Therefore, by checking whether or not there are two or more ON-state detections at the same time in step 505, such erroneous recognition is prevented and the determination of the presence or absence of the wraparound phenomenon is made more reliable.
[0043]
FIG. 9 is a diagram illustrating the count of the number of newly pressed keys according to the present embodiment. This figure shows an example of the memory map of the temporary scan memory, as in FIG. 7 or 8, where “1” represents the key ON state and “0” represents the key OFF state. As in FIGS. 7 and 8, each row and each column are interchanged and displayed diagonally.
In the present embodiment, as described above, the keyboard scan result is temporarily stored in the temporary scan memory in the memory map format. In step 505, this is compared with the definite scan memory, and a difference is taken to extract it as a change bit shown in FIG. If there are two or more lines where the bit value of the low-side line is not 00h, it means that two or more keys have been pressed simultaneously.
[0044]
If it is determined in the above-described method that there are not two or more at the same time in step 505, it means that there is no wraparound, so the key is determined and stored in the determined scan memory.
If it is determined in step 505 that there are two or more at the same time, this means that a wraparound phenomenon has occurred.
[0045]
Thus, according to the second embodiment of the present invention, for a keyboard capable of normal key input of a plurality of keys, such as 6 keys or 8 keys, for example, when performing braille input. Can also implement a wraparound inspection.
[0046]
【Effect of the invention】
As described above, according to the first invention, since the F key rollover technique for the wraparound inspection is realized in one key scan, a high-speed key scan process can be executed. It is possible to make it difficult for the person to analyze the key scan, and safety is increased.
[0047]
According to the second aspect of the present invention, it is possible to realize a wraparound inspection even for a keyboard capable of normal key input of a plurality of keys such as 6 keys or 8 keys, for example, when performing Braille input. it can.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of keyboard control firmware according to a first embodiment of the present invention.
FIG. 2 is a flowchart according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a case where an “A” key is pressed.
FIG. 4 is a diagram illustrating a case where “B”, “C”, and “D” keys are pressed simultaneously.
FIG. 5 is a diagram illustrating a memory map of a temporary scan memory when a plurality of keys are pressed.
FIG. 6 is a flowchart according to a second embodiment of the present invention.
FIG. 7 is a diagram for explaining column-side line counting according to the embodiment;
FIG. 8 is a diagram for explaining the count of the row line according to the embodiment.
FIG. 9 is a diagram for explaining the count of the number of newly pressed keys according to the embodiment.
[Explanation of symbols]
1 ... Keyboard control firmware
101 ... Key buffer
102 ... Final scan memory
103 ... 1st counter
104 ... second counter

Claims (3)

A scan memory for temporarily storing a result of key scanning of a computer keyboard in a memory map format corresponding to one bit per key;
Low side determination means for determining whether or not there is at least one line on the low side where there are two or more ON keys in the memory map stored in the scan memory;
Column side determination means for determining whether or not there is at least one line on the column side where there are two or more ON keys in the memory map stored in the scan memory;
When both the row-side determination means and the column-side determination means determine that there is at least one line having ON keys of two or more keys, two ON state detections by a newly pressed key are simultaneously performed. Simultaneous key press determination means for determining whether or not there has been,
When either the row-side determining means or the column-side determining means determines that there are no more than two ON keys, or the simultaneous key pressing determining means is turned on by a newly pressed key When it is determined that two or more states are not detected at the same time, the content stored in the scan memory is determined as a determination key, and the simultaneous key pressing determination unit is in an ON state by a newly pressed key. A key confirming means for determining that wraparound occurs when it is determined that there are two or more detections simultaneously;
A confirmation memory for storing a confirmation key confirmed by the key confirmation means;
A keyboard characterized by comprising. The keyboard according to claim 1 , wherein the simultaneous key pressing determination unit determines whether or not two or more keys are simultaneously pressed by comparing the scan memory and the fixed memory and extracting the same as a change bit. Wherein when it is determined that there is wraparound key confirmation unit, keyboard according to claim 1 or 2 further comprising an error code transmitting means for transmitting an error code indicating that it is wraparound.

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