Abstract: A method of determining a type of touch plane operator input device comprises sensing the impedance across first and second terminals of a touch plane operator input device to distinguish the touch plane operator input device as being one of at least two different types of touch plane operator input devices. A method of processing an input from a touch plane operator input device comprises determining a first location of a first touch on the touch plane operator input device; determining a second location of a second touch on the touch plane operator input device; comparing the first and second locations to obtain an indication of an amount of difference between the first and second locations; and determining whether the indication of the amount of difference exceeds a predetermined amount. These steps are performed by discrete logic circuitry that provides an event notification to a microprocessor when the indication of the amount of difference exceeds the predetermined amount.

Abstract: A method of determining a type of touch plane operator input device comprises sensing the impedance across first and second terminals of a touch plane operator input device to distinguish the touch plane operator input device as being one of at least two different types of touch plane operator input devices. A method of processing an input from a touch plane operator input device comprises determining a first location of a first touch on the touch plane operator input device; determining a second location of a second touch on the touch plane operator input device; comparing the first and second locations to obtain an indication of an amount of difference between the first and second locations; and determining whether the indication of the amount of difference exceeds a predetermined amount. These steps are performed by discrete logic circuitry that provides an event notification to a microprocessor when the indication of the amount of difference exceeds the predetermined amount.

Abstract: A method of determining a type of touch plane operator input device comprises sensing the impedance across first and second terminals of a touch plane operator input device to distinguish the touch plane operator input device as being one of at least two different types of touch plane operator input devices. A method of processing an input from a touch plane operator input device comprises determining a first location of a first touch on the touch plane operator input device; determining a second location of a second touch on the touch plane operator input device; comparing the first and second locations to obtain an indication of an amount of difference between the first and second locations; and determining whether the indication of the amount of difference exceeds a predetermined amount. These steps are performed by discrete logic circuitry that provides an event notification to a microprocessor when the indication of the amount of difference exceeds the predetermined amount.

Abstract: An improved raster engine adapted to render video data from a frame buffer to one of a plurality of disparate displays is disclosed which comprises an integral bounded video signature analyzer, a hardware cursor apparatus supporting dual scanned displays, programmatic support for multiple disparate display types, multi-mode programmable hardware blinking, programmable multiple color depth digital display interface, and programmable matrix controlled grayscale generation.

Abstract: An arbiter system comprises a plurality of hardware resources, a common resource, and an arbiter. The plurality of hardware resources are divided into groups of hardware resources and are coupled to the common resource and the arbiter. The arbiter controls which of the plurality of hardware resources has priority to access to the common resource. The arbiter includes a group shifting arbiter which shifts priority among the groups of hardware resources and a level shifting arbiter which separately shifts priority among the hardware resources within each of the groups. An error checking value generator system comprises a general purpose DMA controller and an arithmetic circuit. The arithmetic circuit is coupled to receive data from the general purpose DMA controller. The arithmetic circuit generates an error checking value based on the data received from the general purpose DMA controller and based on a polynomial equation.

Abstract: A method of determining a type of touch plane operator input device comprises sensing the impedance across first and second terminals of a touch plane operator input device to distinguish the touch plane operator input device as being one of at least two different types of touch plane operator input devices. A method of processing an input from a touch plane operator input device comprises determining a first location of a first touch on the touch plane operator input device; determining a second location of a second touch on the touch plane operator input device; comparing the first and second locations to obtain an indication of an amount of difference between the first and second locations; and determining whether the indication of the amount of difference exceeds a predetermined amount. These steps are performed by discrete logic circuitry that provides an event notification to a microprocessor when the indication of the amount of difference exceeds the predetermined amount.

Abstract: Driving circuitry for a switch matrix provides a reset voltage to all rows of the matrix in between scans to recharge switch capacitance. Column detection circuitry is disabled in between scans so that column driving circuitry may also `reset` the charge on capacitors reducing the scan time and/or allowing a greater number of switch elements, element size, or EMI suppressing capacitances. Pull-up resistors are supplemented or eliminated through the use of active current sourcing and sinking for the drivers.