Point memory graphic terminal

An image memory graphic terminal of the type comprising:

• - an image memory (14) constitutes by N memory planes (14.sub.1 . . . 14.sub.N), N being an integer at least equal to 1, each plane incorporating a matrix system of memory points, each able to store one bit, each point being defined by an address, the N bits of N points having the same address in the N planes defining a word V of N bits, said memory having an addressing input (14Ad) common to N planes, a control input (14C) common to N planes, N validation inputs (14V.sub.1 . . . 14V.sub.N) and having N binary outputs (14S.sub.1 . . . . . 14S.sub.N);
• - a sequencer (20) having a clock output (20s.sub.1) and control outputs (20s.sub.2);
• - a graphic display processor (22) having an input (22e), a first group of outputs (22s.sub.1) associated with the outputs (20s.sub.2) of the sequencer supplying control signals (SC) defining an access cycle to the memory, a second group of outputs (22s.sub.2) supplying address signals (SAd), a third group of outputs (22s.sub.3) supplying clock and synchronization signals;
• - a video signal generator (16) having N binary inputs (16e.sub.1 . . . 16e.sub.N) connected to N binary outputs of the image memory (14), a synchronization input (16e) connected to the third group of outputs (22s.sub.3) of the graphic display processor (22) and a clock input (16H) connected to the clock output (20s.sub.1) of sequencer (20) and having an output (16s) supplying video and synchronization signals;
• - a video display receiver (18) connected to the video signal generator (16);
• - a management microcomputer (10) having a first group of outputs (10s.sub.1) connected to the input (22e) of the graphic display processor and a second group of outputs (10s.sub.2), characterized in that the terminal also comprises a system (30) for writing or recording in the image memory image texture signals, said system comprising:
• (A) - a circuit (40) for processing the access cycle to the image memory, said circuit incorporating:
• (A.sub.1) - a circuit (41) for the transmission, with a time lag, of the signals for controlling the access cycle to the memory, said circuit having a first input (41e.sub.1) connected to the second group of outputs (20s.sub.2) of sequencer (20) and (22s.sub.1) of the graphic display processor (22) and receiving control signals (SC), a second input (41e.sub.2) connected to the second group of outputs (22s.sub.2) of the graphic display processor (22) and receiving address signals (SAd), a first output (41s.sub.1) supplying control signals delayed by a fixed time (Sc*) and a second output (41s.sub.2) supplying address signals delayed by the same time (SAd*), the first output (31s.sub.1) being connected to the control inputs (14C.sub.1 . . . 14C.sub.N) of the image memory (14) and the second output (41s.sub.2) to the addressing inputs (14Ad.sub.1 . . . 14Ad.sub.N) of said image memory;
• (A.sub.2) - a shaping circuit (42), which has an input (42e) connected to the second group of outputs (22s.sub.2) of the graphic display processor (22), from where it receives address signals (SAd) and an output (42s) supplying signals (x, y) representing coordinates in the planes of the image memory of the point having the address applied to input (42e);
• (B) - a circuit (50) for the determination of the word (V) to be written into the memory, incorporating:
• (B.sub.1) - an operation parametrization circuit (53), which has an input (53e) connected to the second group of outputs (102.sub.2) of microcomputer (10) and receiving from the latter signals defining the operating procedures of the system and having a first output (53s.sub.1) supplying 8 signals, respectively .DELTA.X, .DELTA.Y, .DELTA.H, .DELTA.V, off.sub.x, off.sub.y, E, L, defining a repetitive pattern corresponding to a particular image texture, a second output (53s.sub.2) supplying signals selecting the pattern to be used in the texture to be displayed, a third output (53s.sub.3) supplying signals (V.sub.F, modes) defining one operating mode from among several (with or without a pattern, uniform or transparent background);
• (B.sub.2) - a computing circuit (54) having a first input (54e.sub.1) connected to the output (42s) of the shaping circuit (42) and receiving signals (x, y) and a second input (54e.sub.2) connected to the first output (53s.sub.1) of the parametrization circuit (53) and receiving the 8 signals supplied by said outputs and having first and second outputs (54s.sub.1, 54s.sub.2), said computing circuit (54) being able to:
• - calculate two coordinates .alpha.* and .beta.* from addresses x, y and signals .DELTA.X, .DELTA.Y, .DELTA.H, .DELTA.V, off.sub.x, off.sub.y by the following relations:
• ##EQU8## - determine whether .alpha.* is positive or zero, in which case the circuit calculates a relative coordinate .alpha. equal to .alpha.* modulo .DELTA.X, if not the circuit calculates .alpha. by:
• [.DELTA.X-(.vertline..alpha.*.vertline.modulo .DELTA.X)]modulo .DELTA.X,
• in which .vertline..alpha.*.vertline. represents the absolute value of .alpha.*,
• determine if .beta.* is positive or zero, in which case the circuit calculates a coordinate .beta. equal to .beta.* modulo .DELTA.Y, if not the circuit calculates a relative coordinate .beta. by:
• [.DELTA.Y-(.vertline..beta.*.vertline.modulo .DELTA.Y)]modulo .DELTA.Y
• in which .vertline..beta.*.vertline. represents the absolute value of .beta.*,
• supply at its first output (54s.sub.1) coordinates .alpha. and .beta.,
• determine its coordinate .alpha. is lower than E and, simultaneously, whether coordinate .beta. is lower than L;
• supply on its second output (54s.sub.2) a signal (DANS) determining whether the preceding condition is or is not satisfied;
• (B.sub.3) - a pattern memory circuit (55), constituted by memories containing information defining different types of pattern and, for each type, several patterns, said circuit incorporating a control input (55e.sub.1) connected to the first output (54s.sub.1) of computing circuit (54) and receiving the relative coordinates (.alpha.,.beta.), a second selection input (55e.sub.2) connected to the second output (53s.sub.2) of the operation parametrization circuit (53), said input (55e.sub.2) receiving selection signals (CHOIX) of one pattern from among several, a third input (55e.sub.3) connected to output (10s.sub.2) of computer (10) and receiving loading signals, and an output (55s) supplying a signal (V.sub.M), which can be written into the image memory for the selected pattern;
• (B.sub.4) - a configuration selection circuit (56), which has a first input (56e.sub.1) connected to the third output (53s.sub.3) of the operation parametrization circuit (53) and which receives signals (V.sub.F, modes) determining an operating mode, a second input (56e.sub.2) connected to the output (55s) of the pattern memory circuit (55) and receiving the signal (V.sub.M), a third input (56e.sub.3) connected to the second output (54s.sub.2) of the computing circuit (54) and receiving the signal (DANS), a fourth input (56e.sub.4) connected to the first output (41s.sub.1) of the memory cycle transmission circuit (41) and receiving the delayed controlled signal (SC*), said circuit (56) being able, as a function of the signal (DANS) and the signal determining the operating mode, to validate the control cycle (SC*) and determine, as a function of the signal V.sub.M the word with N bits (V) to be written into the image memory, said circuit having a first group of outputs (56s.sub.1) connected to the control input (14C) of the image memory and supplying signals controlling the writing into the memory, and a second group of outputs (56s.sub.2) connected to the N validation inputs (14V.sub.1 . . . 14V.sub.N) of the image memory and supplying the word (V) to be written into said memory.