Hi John, Sorry for the late answer, I had hard time using the PRUs and I am now going to use the IIO ADC driver, I am able to read the sample with the cat command in /sys/bus/iio/devices/iio:device0/in_voltage3_raw However I am not able to use Libiio in order to read data from a user space application, I am reading (nil) instead of my data. Do you have any idea of where does the problem comes from ?
Here is the code I am using in the user space : #define _BSD_SOURCE #define _GNU_SOURCE #define _DEFAULT_SOURCE #include <cdk/cdk.h> #include <locale.h> #include <pthread.h> #include <stdbool.h> #include <unistd.h> #include <stdint.h> #include <stdio.h> #include <string.h> #ifdef __APPLE__ #include <iio/iio.h> #else #include <iio.h> #endif struct iio_context *ctx; struct iio_device *dev; struct iio_channel *ch; int main() { ctx = iio_create_default_context(); dev = iio_context_get_device(ctx, 0); ch = iio_device_get_channel(dev, 3); iio_device_attr_write_longlong(dev, "sample_rate", 100); iio_channel_attr_write_double(ch, "scale", 1); iio_channel_enable(ch); char *a = iio_device_get_data(dev); printf("%p\n", a); iio_channel_disable(ch); return 0; } Thanks Pierrick Le lundi 26 février 2018 16:46:11 UTC-5, john3909 a écrit : > > The IIO ADC driver can run at 800K samples per second. Here is the patch > that made that possible. > > https://patchwork.kernel.org/patch/9391487/ > > I can confirm that I have tested the driver at 800Ksps and it works fine > as long as you have a proper low impedance source for each ADC channel. CPU > utilization was about 5% if I recall and that was probably used by the iiod > daemon, which I used to display the waveform on a remote Linux app. > > There is example code in the original Starterware for McSPI, which should > work fine if you are using the PRU low level drivers. > > Regards, > John > > > > > On Feb 26, 2018, at 12:56 PM, pierric...@gadz.org <javascript:> wrote: > > Thanks John, > > I am now working with the starterware_PRU but i did not find examples for > using the McSPI with the PRU, do you think it will be hard to adapt the > initial code to the PRU ? > By the way, looking to the IIO driver documentation, it seems that for the > AM335x chip the max sampling rate is only 200k samples per second which may > not be enough : > http://processors.wiki.ti.com/index.php/Linux_Core_ADC_Users_Guide ; am I > right ? > > > Thanks > > Pierrick > > Le lundi 19 février 2018 23:15:50 UTC-5, john3909 a écrit : >> >> Like I said, it was based on Starterware, so search Github for >> starterware and you will see a project starterware_PRU. It does use the >> mcspi, so it is not a bitbang implementation. >> >> Regards, >> John >> >> >> >> >> On Feb 19, 2018, at 7:33 PM, pierric...@gadz.org wrote: >> >> Thanks John for you answer, I was quit busy last week so I worked on this >> during the Weekend. >> >> Unfortunately, I was not able to find a project that is using the SPI and >> I2C interface with the PRU, I only found this one : >> >> https://github.com/chanakya-vc/PRU-I2C_SPI_master/wiki/SPI-Master-Controller >> But it is using bit banging for the SPI part and not using the on-board >> pull-up resistors for the I2C part. >> >> Concerning the ADC, I'll have a loook at the UIIO drivers in the coming >> days it seems that it meets my need in term of real-time acquisition. >> >> Regards, >> >> Pierrick >> >> -- >> 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...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/74949832-b67c-430f-811e-f3b2fff83852%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/74949832-b67c-430f-811e-f3b2fff83852%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 beagleboard...@googlegroups.com <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/3dc611e5-04e7-45bb-87d4-3c21a5665cec%40googlegroups.com > > <https://groups.google.com/d/msgid/beagleboard/3dc611e5-04e7-45bb-87d4-3c21a5665cec%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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/18b69929-99ca-4e7e-8539-df962a17941d%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.