公开(公告)号：JPS641027A

公开(公告)日：1989-01-05

申请号：JP6205988

申请日：1988-03-17

Applicant: APPLE COMPUTER

Inventor： TOBIN II FUAARANDO

IPC: G06F3/153 ,  G06F12/04 ,  G09G5/06 ,  G09G5/36 ,  G09G5/39 ,  G09G5/395 ,  G09G5/397 ,  G09G5/399 ,  H04N5/907

Abstract: PURPOSE: To give video data to a display device by accessing a pixel data memory by providing an interface means with a CPU, the pixel data memory and a prescribed address means for a video RAM connected between the both. CONSTITUTION: An interface 13 is provided between video equipment (a card) 15 and a CPU 10 of a computer. The card 15 supplies data through an interface circuit 20 to a frame buffer, a controller 22 and a video output circuit 25 and sends address signals and the others through a timing circuit 21 to the controller 22. The controller 22 generates addresses, drives the VRAM of rows and columns and counts them synchronously with the clock of pixel. When the count value of columns is a prescribed value, the count value of rows is increased and the column count value is returned to '0'. Thus, a circuit can be provided for addressing the VRAM while displaying the non-integer or integer number of scanning lines per row of the video memory.