DATA PROCESSING TERMINAL WITH ADDRESSABLE CHARACTERISING STORE

摘要

A data processing terminal incorporates a microprocessor (1) to which various input/output devices such as a communications adapter (5), and a keyboard (7) are connected. A set up store (9) containing terminal characterisation data, a read only store (10) containing microcode, and a random access memory (11) for containing microcode, data, and characters to be displayed on a cathode ray tube (17) are also connected to the data and address busses (2 and 3) of the microprocessor. Refresh control (18) refreshes the CRT. The terminal feature characterisation data in the set up store (9) can be changed from the keyboard when additional features are installed or when the terminal is first installed. Various sequences which are used when the terminal is in ALTER mode are described. The set up store (9) can suitably be formed from a battery-powered CMOS random access memory which will retain data stored therein when the power to the terminal is off. This allows the microprocessor or operator to reconfigure the terminal when power is switched on.