| 摘要 |
PURPOSE:To remove transmitting interruption to an upper processor and to reduce receiving interruption by providing a CRT terminal interface circuit with a CRT character information accumulating area and a receiving data accumulating area for one packet. CONSTITUTION:Ket input data from a terminal 300 are inputted to an interface circuit 100 through a serial transmission port 150. A received character is registered in an FIFO register constituting a receiving buffer 140. If the FIFO register 140 is filled with data, receiving interruption from the terminal 300 is inhibited and data are transmitted to the upper processor 200. The upper processor 200 writes the data in a picture element RAM 120A and a screen property RAM 120B. The interface circuit 100 scans the contents of the RAMs 120A, 120B at a fixed time frequency and transmits the scanned data to a CRT300C of the terminal 300 through a serial transmission port 150.
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