Abstract: A passive coupling structure constructed using printed circuit board traces is used to separate the low and high frequency components of an incoming digital signal. The low and high frequency components of the signal are sent to separate receivers on an integrated circuit. The low frequency receiver may be a conventional level based receiver. The high frequency receiver is a Schmitt-trigger with hysteresis around a DC level or two comparators with separate reference voltages. The outputs of these receivers are combined to produce a receiver output that has increased reliability and noise immunity.

Abstract: Parity and mask bit(s) are stored in a random access memory (RAM) that is coupled to a CAM. This CAM may be part of a TLB. The parity and mask bits(s) are stored in conjunction with the CAM entry write. Upon a CAM query match, the reference parity bit(s) and mask bit(s) stored at the address output by the CAM are output from the RAM. These reference parity bit(s) are compared to parity bit(s) generated from a query data value that is masked by the retrieved mask bit(s). In the absence of a CAM or RAM bit error, the reference parity bit(s) from the RAM and the parity bit(s) generated from the masked query data will match. If a CAM or RAM bit error occurred, these two sets of parity bit(s) will not match and thus an error will be detected. This error may be used as an indication that a false CAM match has occurred.

Abstract: A passive coupling structure constructed using printed circuit board traces is used to separate the low and high frequency components of an incoming digital signal. The low and high frequency components of the signal are sent to separate receivers on an integrated circuit. The low frequency receiver may be a conventional level based receiver. The high frequency receiver is a Schmitt-trigger with hysteresis around a DC level or two comparators with separate reference voltages. The outputs of these receivers are combined to produce a receiver output that has increased reliability and noise immunity.

Abstract: An embodiment of USB device comprises a lookup table in a fixed electronically readable medium comprising a plurality of product identification information entries. The USB device also has an electronically readable index that selects one of the plurality of product identification information entries, and the vendor identification information is stored in a location separate from the index.

Abstract: Via simple electronic circuitry, an analog voltage that tracks the LED light output is produced. This analog voltage is read by an A/D converter to ascertain an approximate relative light output of the LED so that light output compensation can be quickly calculated. A resistor-capacitor circuit is used to approximate the behavior of the LED light output. The output voltage from this circuit is sampled and used along with a sensed ambient temperature to adjust the exposure time of an image capture system.

Abstract: DMA requests from at least one DMA channel with a higher priority than the floppy-disk controller are disabled for at least a portion of a write to floppy DMA operation that includes the transfer of the last byte. This helps ensure that DMA requests generated by the floppy-disk controller will be responded to in under 14 ?S preventing an undetected underrun condition on systems with flawed floppy disk controllers from occurring. An estimate of when the last byte of a write to floppy DMA operation is going to be transferred is made. This estimate may be based upon a fixed interval from the start of the write operation. This estimate may also be based upon readings taken from the byte counter and of the DMA controller and the system timer.

Abstract: The time required to boot a computer is reduced by reducing or eliminating the need to discover many or all devices within the computer and the machine topology. Access panels are monitored so that it is detected when they are opened. For the access panels that have not been opened, it is assumed that the system configuration, topology, devices, etc. have not changed since the last boot process and there is no need to spend time discovering these devices and machine topology. Stored, instead of discovered, configuration information is then used to configure these devices. This reduces the time required to boot since discovery of devices is not performed. A service processor or other logic may be used to detect which access panels are opened. Also, only those elements of the configuration that may be affected by the particular access panels that were opened need to be re-discovered.

Abstract: A pulse clock is generated by a pulse generator from a system clock. This pulse determines when the output of a high fan-in gate is to be latched. The pulse clock also feeds a latch with no pass gate and sets the timing of the high fan-in dynamic gate. Because of the length of the active time of the pulse clock, the high fan-in dynamic gate does not have a holder.

Abstract: Two reference voltages and two differential receivers are used to detect low-to-high and high-to-low transitions on an input signal and set a received signal output. One reference voltage is set near but under the electrical high voltage level and the other is set near but above the electrical low voltage level. The reference voltage that is closest to the input signal is designated as the active reference voltage. When the input signal crosses the active reference voltage digital value of the received signal output is changed. When the input signal then crosses the inactive reference voltage, the inactive reference voltage is made the active reference voltage. A dead-time is then waited where input signal crossings of the active reference voltage are ignored. After the dead-time, input signal crossings of the active reference voltage will change the received signal output.

Abstract: A reference voltage is moved dynamically towards a voltage level of the last received value. The movement takes place over a predetermined fraction of a bit-time. The amount of movement is limited so that successive logical values don't result in an unusable reference voltage level. When the output of a receiver changes, a state machine sequences the selection of analog reference voltage inputs to a multiplexer to move an output reference voltage towards a steady-state signal voltage level for the value that was just received. When the sequence is complete, the state machine keeps the last value selected on the output until the output of the receiver changes value.

Abstract: A method of guaranteeing a minimum sustained data transfer rate to a chosen device connected to a USB bus. A set of filter drivers are inserted in the driver stacks for at least two USB devices. These filter drivers are controlled by a filter driver controller that provides and receives information from the filter drivers. When a particular device needs a minimum sustained bandwidth for a transaction, the filter driver for that device notifies the filter driver controller. The filter driver controller then instructs the filter drivers for at least one other device to start interfering with USB transactions. This interference prevents the interfered with devices from using any of the USB bus bandwidth thereby providing a minimum sustained bandwidth to the non-interfered with device.

Abstract: A reference voltage is moved dynamically towards a voltage level of the last received value. The movement takes place over a predetermined fraction of a bit-time. The amount of movement is limited so that successive logical values don't result in an unusable reference voltage level. When the output of a receiver changes, a state machine sequences the selection of analog reference voltage inputs to a multiplexer to move an output reference voltage towards a steady-state signal voltage level for the value that was just received. When the sequence is complete, the state machine keeps the last value selected on the output until the output of the receiver changes value.

Abstract: A tuned circuit is used to detect wobble clock inversions. The tuned circuit reacts to a wobble inversion with a change in amplitude that may be detected by a threshold detector. A bandpass tuned circuit is used to detect wobble clock inversions. The output of the bandpass tuned circuit is input to a saturating high-gain amplifier such as a comparator. The output of the saturating high-gain amplifier reacts to wobble inversions with a half-cycle that has an increased duration as compared to half-cycles without wobble inversions.

Abstract: A method of operating a static random access memory (SRAM) having a column clear function by performing write operations using a two step process. To perform a write, each cell in a row to be written is preset during a first step. Then, each cell that is to have a zero written to it is cleared using a column clear operation. A column of cells may be cleared by enabling all the rows for clearing, then asserting column clear control signals for each of the columns in the array to be cleared. A subset of columns of a plurality of rows may be cleared by asserting a plurality of column clear signals corresponding to the subset of columns and a plurality of work lines corresponding to the plurality of rows.

Abstract: The junction temperature of an LED is determined. This result is used to determine an initial brightness value of the LED. The initial brightness value is derated by a long-term degradation amount that is determined using a stored indication of the lifetime total on time. The derated brightness value is used to determine an exposure for a capture system. The junction temperature is determined by measuring the ambient temperature and then keeping a running junction temperature determined from the on and off times.

Abstract: A six-drop bus has each driver or receiver terminated at the characteristic impedance of Z0. Each driver or receiver is connected to a segment of transmission line with a characteristic impedance of Z0. Three of these segments are connected at a first point. The other three of these segments are connected at a second point. The first and second points are connected by a central transmission line with a characteristic impedance of Z0/3.

Abstract: A four-drop bus has each driver or receiver terminated at the characteristic impedance of Z0. Each driver or receiver is connected to a segment of transmission line with a characteristic impedance of Z0. Two of these segments are connected at a first point. The other two of these segments are connected at a second point. The first and second points are connected by a central transmission line with a characteristic impedance of Z0/2.

Abstract: A low-cost EMI shield that fits around an integrated circuit package to absorb electromagnetic energy and dissipate it as heat. The shield is not ohmically conductive so it may contact electrically active conductors without affecting the operation of the circuit. EMI is prevented from being radiated by and around an integrated circuit package by a perimeter of material that is lossy to high-frequency electromagnetic currents. This perimeter is fitted around an integrated circuit package such that the gap between a heat sink or other top conductor and the printed circuit board is completely closed by the lossy material. This provides not only a line-of-sight obstruction to RF currents, but also provides a lossy return path to close the circuit loop for currents on the skin of the heat sink. Since the material is lossy, rather than purely conductive, it can be used with a less than perfect ground attachment.

Abstract: A module array includes a lead-in transmission line from a driving source. The lead-in transmission line ends with a series impedance between the lead-in transmission line and a star node. The star node has a terminating impedance between it and a termination voltage. At least two branch transmission lines diverge from the star node. Modules connect to the branch transmission lines in a comb topology.

Abstract: A set of discrete transistor sizes spread in an exponential manner over a specified range is the basis for adjusted transistor sizes used to optimize a circuit. One of the discrete transistor sizes may be the original transistor size or other starting point for the optimization.