> On Mar 18, 2016, at 1:06 PM, Audrey <a...@smith.edu> wrote: > > Hm. > > Sorry, but unfortunately I'm still quite a bit lost. What should I be doing > to dev/iio:device0 (open?) in order to do the following: > echo 1 > in_voltage0_en >From memory,
echo 1 > /sys/bus/iio/devices/iio:device0/scan_element/in_voltage0_en > echo 1 > buffer/enable echo 1 > /sys/bus/iio/devices/iio:device0/buffer/enable Regards, John > > I'm assuming that I should be able to see in_voltage0_en and buffer in the > folder /sys/bus/iio/devices/iio:device0 but I currently do not see those > attributes/drivers/folders/buffers/whatever-you-want-to-call-them. > > Typing > root@beaglebone:/dev# open iio:device0 > doesn't seem to do anything. > > Do you think you could break your steps down even further? > > Thanks. > > On Friday, March 18, 2016 at 3:49:39 PM UTC-4, john3909 wrote: > It is a driver, so you can open, poll and read from /dev/iio:device0 > > For a quick test, do the following: After you enable the various > scan_channels, start the buffer and then do the following: > > dd if=/dev/iio:device0 of=~/test.txt > > Press ctrl-C to stop capture. > > Use hexdump to view the file. > > Regards, > John > > > > >> On Mar 18, 2016, at 12:37 PM, Audrey <ao...@ <>smith.edu >> <http://smith.edu/>> wrote: >> >> It says: >> root@beaglebone:/dev# cd iio:device0 >> -bash: cd: iio:device0: Not a directory >> root@beaglebone:/dev# cat iio:device0 >> cat: iio:device0: Invalid argument >> >> >> On Friday, March 18, 2016 at 3:25:13 PM UTC-4, john3909 wrote: >> The buffer is available here: >> >> /dev/iio:device0 >> >> Because the driver uses interrupts, you won’t get the speed you want. The >> driver has to be updated to use DMA if you want to use full speed. Reading >> from the buffer will reduce your CPU load compared to using LDR_PATH because >> this interface blocks until a sample is available, but not long enough for >> the thread to sleep. To use DMA, IIO have introduced a DMA framework and >> most of what you need is already available. However, IIO are going to be >> updating the IIO DMA framework to do zero copy between the kernel module and >> the socket interface, using MMU maps. >> >> Regards, >> John >> >> >> >> >>> On Mar 18, 2016, at 11:21 AM, Audrey <ao...@ <>smith.edu >>> <http://smith.edu/>> wrote: >>> >>> Hi everyone, >>> >>> First of all, thank you everyone for trying to help me. I appreciate >>> everyone's input. >>> >>> I took everyone's advice, and have moved away from bash to C++. It's >>> clocking at about 2 milliseconds, but I would really like it to go down >>> into the microsecond range: >>> /** Simple LDR Reading Application >>> * Written by Derek Molloy for the book "Exploring BeagleBone: Tools and >>> * Techniques for Building with Embedded Linux" by John Wiley & Sons, 2014 >>> * ISBN 9781118935125. Please see the file README.md in the repository root >>> * directory for copyright and GNU GPLv3 license information. */ >>> >>> #include<iostream> >>> #include<fstream> >>> #include<string> >>> #include<sstream> >>> using namespace std; >>> >>> #define LDR_PATH "/sys/bus/iio/devices/iio:device0/in_voltage" >>> >>> int readAnalog(int number) >>> { >>> stringstream ss; >>> ss << LDR_PATH << number << "_raw"; >>> fstream fs; >>> fs.open(ss.str().c_str(), fstream::in); >>> fs >> number; >>> fs.close(); >>> return number; >>> } >>> >>> int main(int argc, char* argv[]) >>> { >>> cout << "Starting the readLDR program" << endl; >>> int value; >>> int i=1; >>> while (true) >>> { >>> float value = (float)readAnalog(0)/4095*1.8; >>> cout <<"V= " << value << endl; >>> cout << i << endl; >>> i++; >>> } >>> return 0; >>> } >>> >>> Thank you TJF for pointing me to libpruio. I'll use it later if I need it, >>> but for now I rather not use the PRU if I don't need to. >>> >>> So I noticed this thing where I can't see the buffer, or scan_elements, or >>> mode in iio:device0, and I wonder if I'm not enabling the adc dto properly >>> or something: >>> root@beaglebone:/sys/bus/iio/devices/iio:device0# ls -l >>> total 0 >>> -r--r--r-- 1 root root 4096 Mar 1 20:51 dev >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage0_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage1_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage2_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage3_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage4_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage5_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage6_raw >>> -rw-r--r-- 1 root root 4096 Mar 1 22:03 in_voltage7_raw >>> -r--r--r-- 1 root root 4096 Mar 1 20:51 name >>> drwxr-xr-x 2 root root 0 Mar 1 20:51 power >>> lrwxrwxrwx 1 root root 0 Mar 1 20:50 subsystem -> ../../../../../bus/iio >>> -rw-r--r-- 1 root root 4096 Mar 1 20:50 uevent >>> >>> This is what I've been doing to "enable" the adc (although I don't really >>> know what it is doing. I can't find the file cape-bone-iio in bbb, and if I >>> try echo cape-bone-iio > test.txt, it is just a regular string.): >>> echo cape-bone-iio > /sys/devices/bone_capemgr.*/slots >>> >>> I tried searching for /driver/iio/adc/ti_am335x_adc.c, but I can't find it >>> (there's nothing in root@beaglebone:/sys/bus/iio/drivers#). Could you >>> perhaps specify the full filepath? >>> >>> Thanks. >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> <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 beagleboard...@ <>googlegroups.com <http://googlegroups.com/>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> <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 beagleboard...@googlegroups.com <>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > > -- > For more options, visit http://beagleboard.org/discuss > <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 beagleboard+unsubscr...@googlegroups.com > <mailto:beagleboard+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout > <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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
