Abstract: A microcomputer terminal system having a list mode of operation for the video refresh circuit. Stored in the main memory are list address pointers. Video circuits read a list address pointer at a designated location in the main memory. The list address pointer points the video circuits to the beginning of a list. The main memory stores the list. The list comprises control data, character count and a data address pointer. The data address pointer of the addressed list is read by the video circuits. By reading the data address pointer of the addressed list, the video circuits are pointed to the storage location of the main memory for the character data to be displayed on the video screen. On each refresh cycle of the video screen, the video circuits progress element-by-element through the list generating the display. The video circuits return to the beginning of the addressed list for the next refresh cycle.

Abstract: A microcomputer terminal system in which all input/output devices communicate with a microcomputer through a system bus. The microcomputer includes a microprocessor and a memory. Programs are stored in the memory of the microcomputer. The input/output devices include a keyboard and a cathode ray tube display. Through a read/write memory for the input/output devices interconnecting the keyboard and the cathode ray tube display with the system bus, the microprocessor, the keyboard and the cathode ray tube display perform their respective internal operations independently of the other.The keyboard selectively produces signals representing character data and control data in a serial manner. The data, along with a strobe signal, are entered into a keyboard encoder circuit and from there into the read/write memory for the input/output devices and thence to the read/write segment of the microcomputer memory.

Abstract: A microcomputer terminal system in which all input/output devices communicate with a microcomputer through a system bus. The microcomputer includes a microprocessor and a memory. Programs are stored in the memory of the microcomputer. The input/output devices include a keyboard and a cathode ray tube display. Through a read/write memory for the input/output devices interconnecting the keyboard and the cathode ray tube display with the system bus, the microprocessor, the keyboard and the cathode ray tube display perform their respective internal operations independently of the other.The keyboard selectively produces signals representing character data and control data in a serial manner. The data, along with a strobe signal, are entered into a keyboard encoder circuit and from there into the read/write memory for the input/output devices and then to the read/write segment of the microcomputer memory.