Hi William, I did read that article you sent me. I was unable to follow the Driver Configuration bit, but as far as the continuous mode is concerned, after careful re-reading of the article, I think I understand that you are trying to tell me that I should be in the /dev/iio:device0 directory to read the continuous mode. However, my problem is that buffer, scan_elements, and mode, which the article says are used to set up the continuous mode, should be in the /sys/bus/iio/devices/iio:device0 directory. And that was where I was in, but I could not find them, which is my current problem.
John3909, my kernel version is 3.8.13-bone70. I think if this doesn't pan out, I will be looking into using the PRU, although I would like to understand the current system better before moving on to something more complicated. Thanks everyone for your help! On Friday, March 18, 2016 at 5:59:01 PM UTC-4, William Hermans wrote: > > Audrey, > > Please read the link I gave you a couple weeks ago . . . > http://processors.wiki.ti.com/index.php/AM335x_ADC_Driver's_Guide#Continuous_Mode > > Everything you need to know to use the ADC is explained on this page. But > from your last post, and the paths you've shown us. You're in the wrong > directory. Essentially, you're still in the one-shot directories, which are > completely separate from the continuous mode directory structure. > > On Fri, Mar 18, 2016 at 1:46 PM, John Syne <[email protected] > <javascript:>> wrote: > >> What is your kernel version? >> >> Regards, >> John >> >> >> >> >> On Mar 18, 2016, at 1:22 PM, Audrey <[email protected] <javascript:>> >> wrote: >> >> It says: >> root@beaglebone:/# echo 1 > >> /sys/bus/iio/devices/iio:device0/scan_element/in_voltage0_en >> -bash: /sys/bus/iio/devices/iio:device0/scan_element/in_voltage0_en: No >> such file or directory >> >> and I can't find scan_elements in sys/bus/iio/devices/iio:device0 >> root@beaglebone:/sys/bus/iio/devices/iio:device0# ls -l >> total 0 >> -r--r--r-- 1 root root 4096 Mar 1 21:13 dev >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage0_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage1_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage2_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage3_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage4_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage5_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage6_raw >> -rw-r--r-- 1 root root 4096 Mar 1 21:13 in_voltage7_raw >> -r--r--r-- 1 root root 4096 Mar 1 21:13 name >> drwxr-xr-x 2 root root 0 Mar 1 21:13 power >> lrwxrwxrwx 1 root root 0 Mar 1 20:47 subsystem -> >> ../../../../../bus/iio >> -rw-r--r-- 1 root root 4096 Mar 1 20:47 uevent >> >> >> On Friday, March 18, 2016 at 4:15:00 PM UTC-4, john3909 wrote: >>> >>> >>> On Mar 18, 2016, at 1:06 PM, Audrey <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 >>>>> --- >>>>> 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]. >>>>> 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]. >>>> 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]. >>> 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:>. >> 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:>. >> 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. 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