HP 13255-91126 Graphics Display Module Dec77 free download

File name 13255-91126_Graphics_Display_Module_Dec77.pdf

HP 13255 GRAPhICS DISPLAY MODULE Manual part No. 13255-91126 REVISED DEC-12-77 DATA TERMINAL TECHNICAL INFORMATION HEWLETT ir PACKARD Printed in U.S.A. 13255 13255-91126/02 Graphics Display Module PEV DEC-12-77 1.0 INtRODUCTION. The Graphics Display Module is used with the Graphics M-controller MOdule, Top Plane connector and controller Connector Assemblies. The Granhics Display Module contains the storage for the 2b4XX Data Terminal graphics display 720 X 360 screen dot matrix. The read-write memory is accessible throuah the Graphics M-Controll~r and terminal bus for memory mOdification and test and through the Display Controller Module for display. It is organized as a 16,384 X 16 bit word linear array. The mOdule uses 16 lo-pin MOS RAMS each organized 16,384 X 1 bit. t.l OPERATION. The graohics display memory is read by the Graphics M-Controller during the visible portion of the terminal video display, ~nd modified durina the horizontal and vertical sweep retrace times. The memory modification consists of modifying 1 bit at a time and may oe a loqical operation with the current state, tnp output of a serial pattern memory, or unconditionally set to '1' '0' or to the same state as the serial pattern memory output. The pattern memory output may be scaled so that the ratio between the pattern memory bits and the memory bits may be chanoed from 1 to 16. The display memory bits are displayed such that normally there is a one-to-one correspondence between the memory and display bits, automatic refresh is provided since every memory address is read during one "frame". In Zoom mOde the scaling Or zoom ratiO may be changed from 1 to 16. Since the refresh is no longer automatic the last display bit of each blOCK of repeated display bits in the 'x' and '1' direction is blanked, thus providing time for the memory refresh operation (durinq the 'X' blanked lines) In addition, the 'window' resulting from Panninq while in Zoom mode requires that the memory to be displayed on bit boundaries, the necessary memory word presnifting is done prior to toe heginning of each display line. HP 13255 GRAPhICS DISPLAY MODULE Manual part No. 13255-91126 R~VISED DEC-l2-77 ----------------------------------------------------------------------------