Hi, I simply added
&tscadc { status = "okay"; }; &am335x_adc { ti,adc-channels = <0 1 2 3 4 5 6 7>; }; to the end of am335x-boneblack.dts. Date: Mon, 23 Mar 2015 15:07:04 -0700 From: matthew.mcne...@gmail.com To: beagleboard@googlegroups.com CC: dajiang...@gmail.com; malaa...@elisanet.fi Subject: Re: Reading from ADC hangs Hi Matti, Would you please provide details on which dts entries (or maybe a link to the entire dts file!) you're specifying in order to get ADC working with 3.18? Thanks! On Monday, March 2, 2015 at 1:04:39 PM UTC-5, mala...@elisanet.fi wrote: On Thursday, February 26, 2015 at 5:18:51 PM UTC+2, dajia...@gmail.com wrote:Hi, How come in my system, there is no /sys/bus/iio/devices/iio:device0?Under /sys/bus/iio/devices/, there is only one file iio_sysfs_trigger, which is a symbolic link to some other directory.Is there any configuration I need to do?I am using the latest BB black Rev C by Element14. It is OS is 3.8.13-bone47. Thx. Hi, You need to enable the ADC either by enabling the correct "cape" with capemgr (only in kernel 3.8.*, see e.g. http://hipstercircuits.com/reading-analog-adc-values-on-beaglebone-black/), or by enabling it in the .dts-file (later kernels, such as the 3.18.4 which I'm using). Matti On Wednesday, February 25, 2015 at 8:36:18 PM UTC+8, mala...@elisanet.fi wrote:Thanks for the suggestion. I'll keep that in mind if I need higher sampling rates. However, I did find a way to read ADC through IIO so that it doesn't hang. First set up the channels and the buffer through sysfs: echo 1 > /sys/bus/iio/devices/iio\:device0/scan_elements/in_voltage0_en echo 256 > /sys/bus/iio/devices/iio\:device0/buffer/length echo 1 > /sys/bus/iio/devices/iio\:device0/buffer/enable and then read from /dev/iio:device0. This way I can achieve about 8 kHz sampling rate with a single channel, 4 kHz with two channels and down to ~300 Hz with all eight channels. -- 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.