Packet-based mouse data protocol
First Claim
1. In a method of operating a cursor control device having plural buttons, at least one position sensor, and circuitry for encoding data from said buttons and sensor into plural byte packets for transmission to an associated computer, an improvement comprising formatting each byte of the packet to include plural data bits, with a sync bit at an end thereof, the sync bit in the first byte having a value of "1" and the sync bit in succeeding bytes having a value of "0," wherein the first byte of the packet can be unambiguously distinguished from later bytes of the packet.
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Accused Products
Abstract
Data is transmitted from a mouse to a host computer in accordance with a 3-byte packet protocol. The first byte includes bits indicating the status of first and second buttons on the mouse. The first bit of each byte serves as a sync bit. The sync bit has a value of "1" in the first byte and a value of "0" in each of the second and third bytes. Data representing movement of the mouse in two dimensions is encoded as two 8-bit twos-complement integers which are transmitted as part of the three-byte packet.
144 Citations
29 Claims
- 1. In a method of operating a cursor control device having plural buttons, at least one position sensor, and circuitry for encoding data from said buttons and sensor into plural byte packets for transmission to an associated computer, an improvement comprising formatting each byte of the packet to include plural data bits, with a sync bit at an end thereof, the sync bit in the first byte having a value of "1" and the sync bit in succeeding bytes having a value of "0," wherein the first byte of the packet can be unambiguously distinguished from later bytes of the packet.
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12. In a method of operating a cursor control device having plural buttons, at least one position sensor, and circuitry for encoding data from said buttons and sensor into plural byte packets for transmission to an associated computer, an improvement comprising generating an 8-bit, signed two'"'"'s complement representation of relative displacement in the X-direction comprising bits X7, X6, X5, X4, X3, X2, X1, and X0, and generating an 8-bit, signed two'"'"'s complement representation of relative displacement in the Y-direction comprising bits Y7, Y6, Y5, Y4, Y3, Y2, Y1 and Y0, and in which the method further includes:
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formatting the first byte to include successive bits X6, X7, Y6, and Y7 in sequence; formatting the second byte to include successive bits X0-X5 in sequence; and formatting the third byte to include successive bits Y0-Y5 in sequence wherein the 8 bit representation of the relative displacement fits into a byte of less than 8 bits reducing the overall number of bits transmitted by the cursor control device.
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13. A cursor control device comprising:
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plural buttons; first means for providing data relating to relative position; second means for encoding data from said buttons and said first means into plural byte packets for transmission to an associated computer, each byte consisting of seven bits B0-B6, said second means formatting the first three bytes of the packet as follows;
space="preserve" listing-type="tabular">______________________________________ B6 B5 B4 B3 B2 B1 B0 ______________________________________ Byte 1 1 Left Right Y7 Y6 X7 X6 Byte 2 0 X5 X4 X3 X2 X1 X0 Byte 3 0 Y5 Y4 Y3 Y2 Y1 Y0 ______________________________________where Left is a bit corresponding to a state of a left cursor control button, Right is a bit corresponding to a state of a right cursor control device button, Y0-Y7 is an ordered sequence of bits representing, in signed two'"'"'s complement from, a displacement in the Y-direction, and X0-X7 is an ordered sequence of 8 bits representing, in signed two'"'"'s complement form, a displacement in the X-direction wherein the first byte of the packet can be unambiguously distinguished from later bytes of the packet. - View Dependent Claims (14)
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- 15. In a cursor device having plural buttons, at least one position sensor, and formatting circuitry for encoding data from said buttons and sensor into plural byte packets for transmission to an associated computer, an improvement wherein said formatting circuitry formats each byte of the packet to include plural data bits, with a sync bit at an end thereof, the sync bit in the first byte having a value of "1" and the sync bit in succeeding bytes having a value of "0," wherein the first byte of the packet can be unambiguously distinguished from later bytes of the packet.
Specification