I have seen logic analysers that claim to get a sample rate up to 1 MHz from the parallel port depending on hardware. https://jwasys.home.xs4all.nl/old/diy2.html
If I remember correctly, isn't there a 18.5 Hz interrupt/clock as standard on the pc? Might be useful to know for original poster. Den ons 2 jan. 2019 16:47 skrev stecdose <stecd...@gmail.com>: > > On 12/31/18 8:14 PM, Tom Ehlert wrote: > >> I thought about having an ISR capturing the data being called at capture > >> rate, which should be something around 100kHz to 150kHz > > unlikely. expect *each* inp()/outp() operation to use O(500ns) > > > > there is also a notable delay between applying an input 0/1 voltage, > > and this voltage available as inp() > > > > usually people read until 2 readings are identical. > > > > try polling first to get an idea what input rate will be possible. > > I tried now a with a small Turbo-C program that reads the parallel port > data regsiter in a loop and this gives me ~20kHz, also not constantly. > Every time i try it varies by +-5kHz. > > I expected it to be a bit faster... Maybe I can get away with an > external microcontroller sampling the data and periodically raising the > external parallel port IRQ and copying the data from parallel port with > DMA. > > But this would be total overkill, all this effort could bring up a logic > analyzer on another platform more easily... > > One of those 30$ STM32-boards with a 4.3" display would do several > megahertz signals... > > >> There should be plenty of time on this machine to process data after > >> capturing from parallel port. > > yes. with real time linux. > > > > > Hmm I already tried FreeRTOS on x86, it was not that easy to set up, but > once it ran, it felt really cool, to program a PC like a microcontroller. > > I think getting RT-Linux to run on this machine would be a greater > benefit than FreeRTOS, because it brings more of a "complete" operating > system (compiler, tools, networking stuff, games, ...) > > Anyway, this is not my project right now, it will be some day in future... > > Thanks for your answer!! > > Nils > > > > _______________________________________________ > Freedos-user mailing list > Freedos-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-user >
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