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
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