The computer system of this invention has, a simple processing unit for providing most data processing by the computer system under control of a read-only memory which contains instructions and other data for the CPU. The system also includes a random access memory, a keyboard, a video terminal, and a port device in the form of a tape recorder/player. A master clock initiates timing used throughout the system. A multi-line data bus interconnects the CPU and the different memories of the system including the keyboard and the video RAM. Bi-directional communication is possible on the data bus. The addressing of these different memories is by way of an address bus from the CPU, which is a uni-directional bus. Data to be operated upon is stored in the random access memory. The keyboard is used for inputting data to the CPU and the video terminal is used for displaying data. A reset switch is operable by the operator of the computer system to reset the system by forcing the CPU to a known address. Also, at power-up, the CPU is reset starting at a preselected address. The CPU may also be restarted by means of the manual reset switch starting with execution of instructions from a predetermined address in the ROM. The reset switch couples to the interrupt input of the microprocessor. The power-up circuit couples to the reset input of the microprocessor.
This application is a continuation of application Ser. No. 466,207, filed Feb. 14, 1983, now abandoned, which is a continuation of Ser. No. 168,427, filed July 10, 1980, now abandoned, which is a division of Ser. No. 926,957, filed July 21, 1978, now abandoned.
A system architecture of a personal computer is modified to increase overall performance including the display of video signals while maintaining PC compatibility. A video control circuit is positioned onto a motherboard so that it directly interfaces with a local bus of a processing unit. The processing unit may include, for example, a 80386 microprocessor and a 82396 cache controller or simply a 80386 or 80486 microprocessor. As a result, the processing unit can directly read data from and write data to the video controller without always having to traverse the peripheral bus. Video data is thus transferred at the rate at which the processing unit operates and not at the slower rate of the peripheral bus.
A clock circuit for a microcomputer having a clock input, a halt mode state output and an interrupt input, comprises: a clock pulse generator having an output, a switch for applying a pulsed output to the interrupt input of the microcomputer to indicate a start of operation; a latch receptive of the output of the switch to change from a first state to a second state, gates receptive of the output of the clock pulse generator and the latch for applying clock pulses to the microcomputer when the logic is in the second state and preventing the application of clock pulses to the microcomputer when the logic is in the first state and circuitry for applying the halt mode state output to the logic circuit to disable same from the second state to the first state.
A video card for processing a video signal comprises an interchangeable connector module and a video processing module. The interchangeable connector module has a specific configuration. The video processing module has a connector for coupling the interchangeable connector module. The specific configuration of the interchangeable connector module sets the characteristics of the video processing module.
A workstation for processing and producing a video signal comprises a video input system, a video graphics processor, and a video output system. The video input system may comprise a video input module, a first video pipeline, and a second video pipeline. The video output system may comprise a receiver, a video pipeline and a video output module. In addition, the video input system may comprise a video input module having a specific configuration and a video processing module having a connector for coupling the video input module, the specific configuration of the video input module setting the characteristics of the video processing module. The video output system may comprise a video processing module having a connector for coupling a video output module and a video output module having a specific configuration, the specific configuration of the video output module setting the characteristics of the video processing module.
A workstation for processing and producing a video signal comprises a video input system, a video graphics processor, and a video output system. The video input system may comprise a video input module, a first video pipeline, and a second video pipeline. The video output system may comprise a receiver, a video pipeline and a video output module. In addition, the video input system may comprise a video input module having a specific configuration and a video processing module having a connector for coupling the video input module, the specific configuration of the video input module setting the characteristics of the video processing module. The video output system may comprise a video processing module having a connector for coupling a video output module and a video output module having a specific configuration, the specific configuration of the video output module setting the characteristics of the video processing module.
