Design of a microprogrammed alphanumeric terminal
F. Dromard · 1974
The development of LSI microprocessors in terminal controllers enables tasks decentralization and increases the terminal performances for a lower cost. This paper describes a small alphanumeric display giving the user the opportunity of programming in a high level language, in a conversational mode. The microprocessor manages: the control of the keyboard, the display of the current sentence, the exchanges with the main computer. It also controls a syntactic filtering of the user's sentence. The keyboard is composed of alphanumeric and function keys. The alphanumeric text is not processed, while function keys are considered as delimiters. Each keyword of the language is assigned a keyboard position. The microprocessor has a grammar defining the syntactic rules; the processor generates a coded string corresponding to the sentence. This will be transmitted only if the sentence is correct. The user can modify at any instant the elements of his sentence. The terminal performances can be extended to several languages. To change the language, one has only to replace the grammar and the corresponding microprograms. These ones, such as the grammar, can either be resident or they are sent by the main computer, according to the requirements.