Tachistoscopic presentation and millisecond timing on the IBM PC/XT/AT and PS/2: A Turbo Pascal unit to provide general-purpose routines for CGA,Hercules, EGA,and VGA monitors

A review of the literature on adopting microcomputers for use in tachistoscopic research paradigms illustrates the need for a comprehensive package to effectively deal with the wide variety of video displays and microcomputers used in experimental settings. In addition, because of the large number of possible configurations created when video displays and computer systems are combined, there is a need to be able to efficiently drive any such combination without rewriting program code. A Turbo Pascal unit is presented to provide standard tachistoseopic routines compatible with monochrome, CGA, Hercules, EGA, and VGA video technology. Procedures that synchronize both text and graphics mode stimuli with the vertical retrace pulse are given, as are routines to provide access to a timer with better than millisecond precision. Pascal code is described that will run on the IBM PC, XT, AT, or PS/2, as well as on any compatible machine. The versatility of the unit allows the experimenter to use generic video and timer commands that will automatically adapt at run time to the system that is being used, without further experimenter intervention.