ron@vicorp.com (Ron Peterson) (08/24/90)
Does anyone out there have any experience with real-time data aquisition on the Amiga? I have written a level-2 interrupt server (triggered by the ACK signal) to grab about .5 seconds worth of data from the parallel port. The sampling of the data needs to be fairly fast (like in sampling audio frequencies) and precise and REPEATABLE. If I run in a workbench screen the code works well. If I open a screen of my own (640x200) the timing goes to hell even though my server does a Disable() and Forbid(). I seem to remember some talk about this a while back saying something like: the additional screen created some processing overhead via exec or intuition (which couldn't be disabled easily without guruing the operating system.) Or perhaps it had to do with the high screen resolution interfering with the CPU timing due to DMA access so that a 320x200 screen was required instead. Does anyone know or remember? And what are the ways to get around it? Just use 320x200 screens? Just use the 640x200 workbench screen? Is there a way to get the OFF_DISPLAY/ ON_DISPLAY macro's working so that the display could be temporarily disabled? Also, is there a "proper" way to tell if your server (as one of many in a chain) is the intended receiver of the triggering interrupt? It seems that string gadgets also use level-2 interrupts for keyboard I/O. Please reply via email to ron@vicorp.COM. Thanks!