WO2006137642A1

WO2006137642A1 - Method for transmitting scan data of wireless input device and ir protocol therefor

Info

Publication number: WO2006137642A1
Application number: PCT/KR2006/001514
Authority: WO
Inventors: Jae Kwan Lee
Original assignee: Celrun Co., Ltd.
Priority date: 2005-06-22
Filing date: 2006-04-21
Publication date: 2006-12-28
Also published as: KR100701326B1; KR20060134345A

Abstract

The present invention relates to a method for transmitting the scan data of a wireless input device. The method comprises the steps of: when a general key is pressed while a function key remains pressed, successively transmitting a make code for the function key and a make code for the general key; transmitting a break code for the general key when the general key is depressed; and, when the function key remains pressed after the depressing of the general key, re¬ transmitting the make code for the function key before transmitting a make code for a general key to be pressed afterward. When general keys are pressed and depressed for several times while a function key remains pressed, a make code for the function key is generated after the depressing of one general key and before the pressing of another general key. Thus, the transmission error of the make code for the function key can be avoided and the IR protocol can be simplified. Specifically, inputs of two different general keys can be distinguished with a time interval of about 14.4 msec.

Description

METHOD FOR TRANSMITTING SCAN DATA OF WIRELESS INPUT DEVICE AND IR PROTOCOL THEREFOR

Technical Field

[1] The present invention relates to a method for transmitting scan data of a wireless input device. More particularly, the present invention relates to a method for transmitting scan data of a wireless input device used for data input to a set top box. The present invention also relates to an IR protocol for the same. Background Art

[2] Typical examples of input devices are keyboard, mouse, remote control, etc.

Depending on the way of input, they are divided into wired and wireless. Wired input devices are advantageous in that the possibility of data loss is quite low. Thus, whether a general key is used alone or it is used in combination with a function key, they transmit only scan data of each key. But, the wired input devices require cabling and should be located near the electronic devices. Especially, in case the input device is away from the electronic apparatus that receives the input signal from the input device, like a set top box, etc., utilization of wired input devices is quite restricted.

[3] Accordingly, wireless input devices have been used for data input to a set top box.

U.S. Patent No. 4,628,541 discloses a wireless keyboard using IR signals. But, data input using wireless input devices has the risk of data loss during transmission. For example, sometimes, a scan code for a function key (Shift key, Ctrl key, Alt key, etc.) may be loss during the transmission to the set top box even when the function key has been pressed. Differently from general keys, the pressing of a function key affects all the following key codes, not just the key code itself. Thus, the transmission error in the scan code for the function key is much more dangerous than that for the general key.

[4] To solve this problem, Korean Patent No. 196665, owned by Sejin Electronics Co.,

Ltd., discloses a method for transmitting scan data of wireless input device comprising, when the general key is pressed along with the function key, transmitting a make or break code of a function key, and then transmitting a scan code of a general key containing a flag corresponding to the pressed function key to inform that the function key has been pressed. The description of the Korean Patent No. 196665 is incorporated herein by reference.

[5] Table 1 below shows a specific example of the IR (infrared) protocol for a wireless keyboard used in the patent.

[6] Table 1 Byte bit 7 bit 6 bi t 5 bit 4 bit 3 bi t 2 bi t 1 bit O 1 Devi ce ID appl icat ion I -wi ndows P-windows

2 Make = 0

Rredk - 1 FN L-sh i f t R-shift L-AI t R-AI t L-Ur I R-Ct r l

3 key posi t ion code

4 Usei - ID Checksum

[7] As shown in Table 1, the IR protocol used in the patent consists of 4 bytes, the first byte (Byte 1) consisting of device ID and application flags, the second byte (Byte 2) consisting of a make/break flag and function key flags, the third byte (Byte 3) consisting of a key position code and the fourth byte (Byte 4) consisting of a user ID (identifier) and checksum. The IR protocol disclosed in the patent checks the transmission error by transmitting the scan code of the general key including the function key flag, thereby reducing the transmission error of the function key.

[8] However, because the make/break flag and each of the function key flags for each function key are expressed as one bit, the transmission protocol of the patent is susceptible to data transmission error. In other words, the patent suffers from data loss of the function key flags in the transmission of the scan code of the general key. Besides, the protocol of this patent requires 4 bytes of a packet data, which results in slow code transmission. For example, 24.8 msec of time interval is required for distinguishing two adjacent key inputs, thereby retarding data input speed. Disclosure of Invention Technical Problem

[9] The present invention has been made to solve these problems. An object of the present invention is to provide a method that effectively prevents errors involved in the transmission of the function key during the data input and that provides enhanced data input speed. Technical Solution

[10] According to a preferred embodiment of the present invention, there is provided a method for transmitting scan code of a wireless input device, along with a leader informing the transmission of the scan code, which comprises the steps of: when a general key is pressed while a function key remains pressed, successively transmitting a make code for the function key and a make code for the general key; transmitting a break code for the general key when the general key is depressed; and, when the function key remains pressed after the depressing of the general key, re-transmitting the make code for the function key before transmitting a make code for a general key to be pressed afterward.

[11] According to another preferred embodiment of the present invention, there is provided a method for transmitting scan code of a wireless input device, wherein a packet data of the scan code consists of 3 bytes, a first byte being allocated to device ID, flags for left and right mouse clicks and checksum data, a second byte being allocated to application flag data, and a third byte being allocated to key position code data.

[12] According to further another preferred embodiment of the present invention, there is provided a method for transmitting scan code of a wireless input device, wherein the device ID and the flags for left and right mouse clicks consist of 2 bits, respectively and the checksum data consists of 4 bits.

[13] According to yet another preferred embodiment of the present invention, there is provided a method for transmitting scan code of a wireless input device, wherein the checksum data is a value obtained from the XOR operation of five 4-bit units which are obtained by dividing the remaining 20 bits, excluding the 4 bits allocated to the checksum data, into 4 bits each.

[14] According to further yet another preferred embodiment of the present invention, there is provided a method for transmitting scan code of a wireless input device, wherein both the first byte and the second byte of the packet data of the make code are respectively the same with the first byte and the second byte of the packet date of the break code, while the third byte is different each other.

[15] The present invention also provides an IR protocol used for the transmission of scan data of a wireless input device, which consists of a 3-byte packet data, a first byte being allocated to device ID, flags for left and right mouse clicks and checksum data, a second byte being allocated to application flag data and a third byte being allocated to key position code data.

Advantageous Effects

[16] The method for transmitting a scan data of a wireless input device in accordance with the present invention provides the following advantageous effects:

[17] (1) When several general keys are successively pressed and depressed while a function key remains pressed, the make code for the function key is generated again between after depressing of one general key and before pressing of the next general key, and transmitted before transmitting a make code for the second general key. Therefore, the transmission error of the make code for the function key can be avoided.

[18] (2) When a general key is pressed while a function key remains pressed, a make code for the function key and a make code for the general key are transmitted successively. This simplifies the IR protocol. That is, the IR protocol for each key has a 3-byte packet data, which improves the data processing and data input speed. Specifically, inputs of two different general keys can be distinguished with time interval of about 14.4 msec. [19] (3) Since each of the make code and the break code of the packet data for a certain key can have the same data in the first byte (byte 1) and the second byte (byte 2), excluding the third byte (Byte 3) to which the key position code data is allocated, the process of checking packet data errors of the make code and the break code for the same key can be simplified and the data processing speed can be further improved. Brief Description of the Drawings

[20] Fig. 1 is a flow chart illustrating the method for transmitting a scan data of a wireless input device, in accordance with the present invention. Mode for the Invention

[21] The method for transmitting scan data of a wireless input device along with a leader informing the transmission of the scan data in accordance with the present invention, comprises the steps of: the steps of: when a general key is pressed while a function key remains pressed, successively transmitting a make code for the function key and a make code for the general key; transmitting a break code for the general key when the general key is depressed; and, when the function key remains pressed after the depressing of the general key, re-transmitting the make code for the function key before transmitting a make code for a general key to be pressed afterward.

[22] Fig. 1 is a flow chart illustrating the method for transmitting the scan data of a wireless input device according to the present invention. First, the pressing of a certain key of a wireless input device is detected. If the pressed key is a general key, a make code for the general key is generated in the same manner with the conventional method. Then, if the general key is depressed, a break code for the general key is generated. If the general key remains pressed for an extended time, the make codes for the general key are successively regenerated with a predetermined time interval (e.g., 100 msec). Then, if the general key is depressed, a break code for the general key is generated. If the pressed key is a function key, a make code for the function key is generated. Then, if a general key is pressed while the function key remains pressed, a make code for the general key is generated. If the general key remains pressed for an extended time while the function key remains pressed, make codes for the function key are regenerated with a predetermined time interval (e.g., 50 msec) and make codes for the general key are generated again. If the general key is depressed, a break code for the general key is generated. Unless the function key is depressed, a make code for the function key is generated again before transmitting a make code for a general key to be pressed afterward. In other words, if the function key remains pressed after the general key has been depressed, a make code for the function key is generated again, before transmitting a make code for a general key to be pressed later, and then a make code for the general key to be pressed later is transmitted. This allows continuous transmission of the activation or deactivation of the function key, and thus, minimizes the scan code transmission error for the function key.

[23] Suppose that a character key "a" and a character key "b" are being pressed successively while the Shift key remains pressed. When the Shift key is pressed, a make code for the Shift key is generated. Thereafter, if the character key "a" is pressed and depressed while the Shift key remains pressed, a make code and a break code for the character key "a" are generated in sequence. The receiving part receives the scan code for the Shift key and the make code and the break code for the character key and determines that the input character is "A". If the Shift key remains pressed after the character key "a" has been depressed and the character key "b" is pressed, a microprocessor of the wireless input device generates a make code for the Shift key again and generates a make code for the character key "b". If the character key "b" is depressed, a break code for the character key "b" is generated. If the Shift key is depressed after the character key "b" has been depressed, a break code for the Shift key is generated.

[24] As shown in the example, the method for transmitting scan data of a wireless input device in accordance with the present invention is characterized in that, when several keys are pressed and depressed successively while a function key remains pressed, a make code for the function key is generated again between the depressing of one general key and the pressing of another general key. As a result, the transmission error relevant to the make code for the function key can be minimized and the IR protocol can be simplified. More detailed descriptions will be given referring to Table 2 and Table 3 below.

[25] Table 2 shows a specific example of a structure of a packet data used in the transmission of the scan code in accordance with the present invention. [26] Table 2

[27] As shown in Table 2, the packet data used in the transmission method of the present invention consists of 3 bytes. The first byte (Byte 1) comprises device ID, flags for left and right mouse clicks and checksum. Specifically, 2 bits (bit 7, bit 6) of the first byte (Byte 1) are allocated to the device ID (identifier) which informs the kind of an input device. For example, "00" is allocated as the device ID for a keyboard, "01" for a remote control, and "11" for a mouse. [28] The next 2 bits (bit 5, bit 4) are assigned to the flags for left and right mouse clicks.

For a keyboard or a remote control, "00" is allocated. For a left or right mouse click, " 1" is allocated to one of the bits 5 and 4 of the first byte and "0" is allocated to the other.

[29] The next 4 bits (bit 3, bit 2, bit 1, bit 0) are allocated to the checksum. The checksum data checks if the transmitted IR data is a normal one. The checksum data is, preferably, obtained from the XOR operation of five 4-bit units, obtained by dividing the remaining 20 bits, excluding the 4 bits allocated to the checksum data, into 4 bits each. Specifically, the checksum data is obtained from the following Equation 1 :

[30] Equation 1

[31] Checksum = (Left 4 bits of Byte 1)

[32] XOR (Right 4 bits of Byte 2)

[33] XOR (Left 4 bits of Byte 2)

[34] XOR (Right 4 bits of Byte 3)

[35] XOR (Left 4 bits of Byte 3)

[36] If the data allocated to the checksum equals the value obtained from this operation, the IR data in question is recognized as a normal one. To the contrary, if the data allocated to the checksum is different from the operation result, the IR data is an erroneous one and the transmitted data is ignored.

[37] For a keyboard, the second byte (Byte 2) is allocated to application flag data such as

"Normal/Extend", "Power" and "Sleep", etc. In the example shown in Table 2, "Normal/ Extend" which stands for normal and extended keys, respectively, is allocated at the bit 2 of the second byte, "Power" at the bit 1 and "Sleep" at the bit 0. A variety of application flags can be allocated to unassigned bits (bit 7, bit 6, bit 5, bit 4, bit 3), expressed as blank. For a keyboard, the third byte (Byte 3) is allocated to the key position code data. When a key is pressed, a microprocessor of the keyboard checks the key position code and allocates it to the third byte (Byte 3). For a mouse, the second byte (Byte 2) and the third byte (Byte 3) are allocated to X-direction movement data and Y-direction movement data, respectively.

[38] In contrast to the embodiment of Korean Patent No. 196665 shown in Table 1, the packet data in accordance with the present invention does not include function key flags. And, the packet data used in the present invention consists of 3 bytes, which increases the data processing speed and the data input speed. According to the specific embodiment of the present invention, code distinction was carried out with time interval of 14.4 msec when two different general keys were pressed in sequence (Korean Patent No. 196665: about 24.8 msec). Therefore, the data input speed can be increased to accomplish effective data input.

[39] Table 3 shows a specific example of the English- version IR codes in accordance with the present invention. As shown in Table 3, of the 6 code values of the make code and the break code for each of the keys, the first 4 code values are identical. This indicates that both the first byte and the second byte of the packet data of the make code are respectively the same with the first byte and the second byte of the packet date of the break code for the specified key, excluding the third byte (Byte 3) of the packet data to which the key position code data is allocated. In the table 3, the break code was obtained from the equation 2:

[40] Equation 2

[41] Break code = OxFF (hexadecimal) - make code

[42] Because the make code and the break code for an identical key have identical data at the first byte (Byte 1) and the second byte (Byte 2) of the packet data, error checking for the packet data of the make code and the break code is simplified and the data processing speed is further improved.

[43] Table 3

[44]

[45]

Claims

[1] A method for transmitting a scan code of a wireless input device, along with a leader informing the transmission of the scan code, which comprises the steps of: when a general key is pressed while a function key remains pressed, successively transmitting a make code for the function key and a make code for the general key; transmitting a break code for the general key when the general key is depressed; and, when the function key remains pressed after the depressing of the general key, re-transmitting the make code for the function key before transmitting a make code for a general key to be pressed afterward.

[2] The method as set forth in claim 1, wherein a packet data of the scan code consists of 3 bytes, a first byte being allocated to device ID, flags for left and right mouse clicks and checksum data, a second byte being allocated to application flag data, and a third byte being allocated to key position code data.

[3] The method as set forth in claim 2, wherein the device ID (identifier) and the flags for left and right mouse clicks consist of 2 bits, respectively and the checksum data consists of 4 bits.

[4] The method as set forth in claim 3, wherein the checksum data is a value obtained from the XOR operation of five 4-bit units which are obtained by dividing the remaining 20 bits, excluding the 4 bits allocated to the checksum data, into 4 bits each.

[5] The method as set forth in claim 2, wherein both the first byte and the second byte of the packet data of the make code are respectively the same with the first byte and the second byte of the packet date of the break code, while the third byte is different each other.

[6] The method as set forth in claim 2, wherein the break code is obtained by an equation: Equation Break code = OxFF (hexadecimal) - make code

[7] A wireless input device transmitting a scan code based on an IR (infrared) protocol, wherein the IR protocol has a packet data consisting of 3 bytes, a first byte being allocated to device ID, flags for left and right mouse clicks and checksum data, a second byte being allocated to application flag data, and a third byte being allocated to key position code data.