| 摘要 |
A video display terminal is disclosed for use in displaying images of data characters on a display screen. Multi-bit coded data words are supplied by a data source, such as a memory, to a character generator circuit which controls the display of data characters on the face of a video display screen. The coded data words generally fall into three categories; to wit, character codes, control codes and attribute codes. Character codes describe the type of character to be presented on the screen. Attribute codes present modifications or special conditions to be used in conjunction with a displayed character. Control codes are used in conjunction with the control circuitry employed by the character generator. A programmable logic array is interposed between the data source and the character generator and the logic array is programmed so as to interpret the various coded words in various ways to provide output coded words having bit patterns which may be the same or different from that which was inputted from the data source. Consequently, the meaning of an inputted data word may be changed, so that for example, a data word representative of a particular control code may be interpreted to mean a particular character, thereby increasing the available codes to describe characters. |
