Abstract: A method for activating one of a plurality of devices coupled to a communications medium at a first address location and controlled by a host computer. A plurality of extended addresses are provided to the devices, each of the devices having a unique extended address. A command is transmitted from the host computer to the first address. One of the plurality of devices is activated by transmitting the unique extended address of the device on the communications medium, the activated device responding to further commands sent to the first address location.

Abstract: A method for transferring data on a communication medium between a host computer and a plurality of peripheral devices coupled to the medium at a plurality of first address locations, including first and second peripheral devices at a one of the first address locations. The host computer transmits a plurality of first signals to the one of the first address locations requesting any peripheral devices at the one of the first address locations to transmit data to the host computer. The first peripheral device senses the medium to determine if the medium is currently in use. The second peripheral device senses the medium to determine if the medium is currently in use. The first peripheral device transmit data to the host computer when the medium is not in use. The second peripheral device discontinues the transmission of data when the medium is in use and sets an internal collision flag.

Abstract: A communications medium for transmitting data between a plurality of peripheral devices and a host computer. Only one device may talk on the bus at a time and only in response to a command from the host. When a peripheral device needs to be serviced, it sends out a service request signal by holding the bus low after any command signal. The device continues to request service until it receives a talk command from the host computer. When more than one device are the same type (for example, two mice) are coupled to the bus, the host computer assigns new addresses to the devices. Devices detect collisions by sensing a low signal on the bus when they attempt to send a "1".

Abstract: A method for requesting service by a device coupled to a host computer through a communication medium. The host computer sets a service request bit of the device to a first logical value to allow the device to produce a service request signal if the device requires servicing. The device determines that it requires servicing and the device sets an internal flag bit to a first logical value to indicate that the device requires servicing. The device monitors a command from the host computer to see if the command is addressed to the device. If the command is not addressed to the device and if the service request bit is set to a first logical value, then the device generates a service request signal on the medium after the command by holding the communication medium low for a first period of time.

Abstract: A system for detecting the presence of trailing zeros in a number. The number is divided into a plurality of consecutive groups, each group having an address. The system also determines the address location of the lowest order group which contains at least one non-zero bit and which precedes any trailing zeros of the number. Such group defines a target group. The system includes a first circuit for dividing the number into a plurality of consecutive words where each word contains more bits than any group. The first circuit also determines the lowest order word which contains one or more non-zero bits and which precedes any trailing zeros of the number. The system includes a second dividing circuit for dividing each word into a plurality of segments each having a number of bits equal to or greater than the number of bits in the target group.

Abstract: A barrier height voltage reference includes two field-effect transistors which are substantially identical except for their gate-to-channel potential barrier characteristics and which are biased to carry equal drain currents at equal drain voltages. The resulting difference in potential between the gate contacts of the two field effect transistors produces a voltage reference which is substantially independent of operating point, supply potential, and temperature.

Abstract: A barrier height voltage reference includes two field-effect transistors which are substantially identical except for their gate-to-channel potential barrier characteristics and which are biased to carry equal drain currents at equal drain voltages. The resulting difference in potential between the gate contacts of the two field effect transistors produces a voltage reference which is substantially independent of operating point, supply potential, and temperature.

Abstract: A display having variable resolution includes a plurality of discrete light emitting elements arranged in an array. Intervals between elements are quantized into a plurality of levels representing information to be displayed. Selected light emitting elements disposed about the levels are energized by a signal having a duty cycle varied in response to displayable information having a magnitude within a particular one of the plurality of levels.

Abstract: A flat-band voltage reference includes two insulated-gate field-effect transistors, hereinafter IGFETs, which are substantially identical except for their flat-band voltage characteristics and which are biased to carry equal drain currents at equal drain voltages. The resulting difference in potential between the gate contacts of the IGFETs produces a voltage reference which is substantially independent of variances in operating points, supply potentials, and temperature.