I'm no expert, but as far as I can tell there a Linux interrupts handling various things that cannot be disabled. Hence the problem. Kirk
On Tuesday, August 2, 2016 at 4:45:41 PM UTC-7, William Hermans wrote: > > Interrupt can't be used traditionally from userspace. interrupts used > traditionally are kernelspace only. However . . . there are tricks to > getting around, but performance will suffer. Which leaves us back at square > 1 > > On Tue, Aug 2, 2016 at 4:31 PM, evilwulfie <[email protected] > <javascript:>> wrote: > >> Or use a gpio pin that generates an interrupt, mask interrupts do your >> data retrieval re enable interrupts. >> >> you are asking for this kind of an issue when polling. >> >> On 8/2/2016 3:36 PM, William Hermans wrote: >> >> Yes, I have 2-3 suggestions where the first suggestion may not work, but >> are worth attempting. >> >> >> - Upgrade to an RT kernel. >> - Use /dev/mem/ + mmap() >> - Bit bang via a PRU >> - Or write a kernel driver that does all this from kernelspace, but >> writes data to a file userspace hass access to. >> >> >> >> On Tue, Aug 2, 2016 at 3:17 PM, Kirk <[email protected] <javascript:>> >> wrote: >> >>> All, >>> >>> I'm working on a Beaglebone Black project using a MEMS accelerometer >>> chip, the ADXL312. >>> >>> The accelerometer has a pin which goes active each time a new data >>> sample is available to be read. >>> It runs at 3200 Hz. (about 1/3 of a ms per sample) >>> >>> The pin is connected to a GPIO input and I've written code to monitor >>> this pin and grab the data each time. >>> The sampling normally runs for several seconds continuously. >>> >>> The problem is, every once in a while Linux gets busy and apparently >>> interrupts my code and I miss samples. >>> (an overrun bit lets me know this is happening) >>> >>> >>> I'm looking for ideas on how to improve this so data samples are not >>> missed. >>> >>> Any ideas? >>> >>> Kirk >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] <javascript:>. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/beagleboard/564cb216-36a0-4528-874c-f89053d61876%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/beagleboard/564cb216-36a0-4528-874c-f89053d61876%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/CALHSORpCjghcxUpi05Wxx8ak-SF22tsLQk5WfUSQaJrsB-FJ_Q%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/beagleboard/CALHSORpCjghcxUpi05Wxx8ak-SF22tsLQk5WfUSQaJrsB-FJ_Q%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/276e93fe-e0fc-70b0-fa8a-98283c4a1730%40gmail.com >> >> <https://groups.google.com/d/msgid/beagleboard/276e93fe-e0fc-70b0-fa8a-98283c4a1730%40gmail.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/ff874a8c-2eb5-42eb-9524-e9e98166c16e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
