Abstract: A bridge circuit includes a microprocessor having a first I/O port which couples to a SCSI bus and a second I/O port which is coupled through transceivers to an EISA bus. Also, the bridge circuit includes an EISA interface controller, having control lines coupled to the EISA bus and the transceivers, which enable the microprocessor to request and use the EISA bus in time-shared fashion. In order to achieve a high speed of operation, the bridge circuit further includes a memory module, coupled via a private bus to the second I/O port of the microprocessor, which sends instructions on the private bus directly to the microprocessor, without generating any signals on the EISA bus. In addition, in order to prevent deadlocks on the private bus, the bridge circuit includes a deadlock prevention circuit which is coupled to the microprocessor and the private bus and the EISA interface controller.

Abstract: An emulator is comprised of a host processor, an emulator, assist unit, and a memory which are closely coupled together over a co-processor bus. Stored in the memory is a user program which is a sequence of instructions from a user instruction set that is to be emulated, and a control program which is a mixture of host processor instructions and emulator assist unit instructions. In operation, the host processor reads and executes the hosts instructions, and it reads and passes the emulator assist unit instructions to the emulator assist unit for execution in that unit. By this means, the host processor and the emulator assist unit share the emulation tasks; and those tasks which are most difficult for the host are performed by the emulation assist unit.

Abstract: A color cathode ray tube is provided in a color monitor of a video display terminal. The red, green and blue color video input lines are connected to novel control circuits which permit the selection of several different shades of colors for the background or cursor. The circuits which control the background colors are pulse modulated to provide digital shade control of the background color selected and automatically control the color of the cursor so that a contrasting color is provided.

Abstract: An electrical circuit for allowing the use of a TV receiver to display alpha/numeric data includes a pair of monostable multivibrators, logic circuitry and a tri-state gate for shaping and mixing digital horizontal and vertical retrace sync signals and alpha/numeric video signals to create a properly proportioned composite thereof. The circuit further includes an oscillator for generating a RF carrier signal, a field-effect transistor (FET) coupled between the oscillator and the output of the circuit which is adapted to be coupled to the antenna terminal of the TV receiver, and an emitter-follower device which feeds the composite signal to the FET for producing amplitude modulation of the RF carrier signal by the FET and transmission of the modulated signal to the TV receiver antenna terminals.