Hi all!
john3909: Sir! Your post in this topic halped me a lot and pointed me into
right direction,
but I still cannot figure out how to properly load my own version of this
BB-ADC-00A0
<https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/BB-ADC-00A0.dts>
overlay.
Should I put my version under /lib/firmware with some different name, say
/lib/firmware/BB-ADC-00A0.dtbo
and activate it via some key in the uEnv.txt file?
Or should I simply replace original BB-ADC-00A0.dtbo file?
My goal is to increase ADC sampling rate playing with chan-step-opendelay
and chan-step-avg parameters.
Please, anybody, help!
My version.sh script returns the following:
git:/opt/scripts/:[1aa73453b2c980b75e31e83dab7dd8b6696f10c7]
eeprom:[A335BNLT00C01018BBBK009B]
model:[TI_AM335x_BeagleBone_Black]
dogtag:[BeagleBoard.org Debian Image 2018-10-07]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot
2018.09-00002-g0b54a51eee]:[location: dd MBR]
kernel:[4.14.71-ti-r80]
nodejs:[v6.16.0]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/BB-W1-P9.12-00A0.dtbo]
uboot_overlay_options:[disable_uboot_overlay_video=1]
uboot_overlay_options:[disable_uboot_overlay_audio=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg check: to individually upgrade run: [sudo apt install
--only-upgrade <pkg>]
pkg:[bb-cape-overlays]:[4.4.20190215.0-0rcnee0~stretch+20190215]
pkg:[bb-wl18xx-firmware]:[1.20180517-0rcnee0~stretch+20180517]
pkg:[kmod]:[23-2rcnee1~stretch+20171005]
pkg:[librobotcontrol]:[1.0.4-git20190107.0-0rcnee0~stretch+20190108]
pkg:[firmware-ti-connectivity]:[20180825+dfsg-1rcnee1~stretch+20181217]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video
plugdev users systemd-journal i2c bluetooth netdev cloud9ide gpio pwm eqep
admin spi tisdk weston-launch xenomai iio]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1
root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M
net.ifnames=0 quiet]
dmesg | grep pinctrl-single
[ 1.131658] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800
size 568
dmesg | grep gpio-of-helper
[ 1.143650] gpio-of-helper ocp:cape-universal: ready
END
On Saturday, May 19, 2018 at 9:02:37 AM UTC+8, john3909 wrote:
>
> If you are using the latest kernel, you must use u-boot overlays as the
> kernel capemanager as discussed in that article is no longer available.
>
> Regards,
> John
>
>
>
>
>
> On May 18, 2018, at 4:57 PM, [email protected] <javascript:> wrote:
>
>
> John,
> I am still working on this project. I have studied the
> iio_generic_buffer.c and adapted it to save the result of the sampling in a
> csv file. I was testing it today with a waveform generator in the following
> configuration:
> - signal frequency : 1Hz (sin function)
> - signal amplitude: 1V
> - averaging 8 times
>
> I took 1000 samples (buffer length 1000), I then displayed the result and
> instead of a constant horizontal line, i had a sinus-like curve (attached
> as 8 average sin 1Hz 1000 samples).
>
> I tried with higher frequencies such as 20khz and i have a similar result
> but with a "pulse" which, as far as understand corresponds to the signal I
> want to sample ( attached as 8 average sin20kHz).
>
> In both cases, I have some "waves" that does not seems to be linked to the
> frequency of the signal...
>
> I guess something is wrong in my iio_generic_buffer.c like i am not
> reading the data at the right place... but i do not really know what kind
> of error I should look for, I am also attaching it to this post (maybe it
> can help).
> The changes I made are from the patch on this page :
> https://www.teachmemicro.com/beaglebone-black-adc/ and I also modified
> the process_scan(), print2byte() function and the main (~line 650) to save
> the value in a csv file instead of just printing them.
>
> If you can give me an hint of where my error could be it would be very
> helpful.
>
> Thanks a lot,
>
> Pierrick
>
>
> Le mardi 17 avril 2018 00:19:16 UTC-4, john3909 a écrit :
>>
>>
>>
>>
>> On Apr 16, 2018, at 3:40 PM, [email protected] wrote:
>>
>> Hi John,
>> Thanks a lot for this very complete answer ! I think I understand it now,
>> the last point I am not sure about is:
>>
>> ti,chan-step-avg = <1 1 1 1 1 1 1 1> /* 2 sample average */
>>
>> I went through 12.3.3 of the AM3358 Technical Reference Manual and it
>> seems that the setting the averaging value to 1 disable the averaging
>> (instead of setting it to 2) am I right?
>> Thanks again for your help
>>
>> If you look in the AM3358 TRM, it says 0 will disable averaging and 1
>> will average over two samples.
>>
>> From the TRM
>>
>> Number of samplings to average:
>> 000 = No average.
>> 001 = 2 samples average.
>> 010 = 4 samples average.
>> 011 = 8 samples average.
>> 100 = 16 samples average.
>>
>> Regards,
>> John
>>
>>
>> Le mercredi 11 avril 2018 17:00:54 UTC-4, john3909 a écrit :
>>>
>>>
>>>
>>> On Apr 11, 2018, at 6:04 AM, [email protected] wrote:
>>>
>>> Hi John,
>>> Thanks for the help, I looked into the iio_generic_buffer.c example and
>>> i patched it to disable the hardware triggers thanks to the patch presented
>>> on this page : https://www.teachmemicro.com/beaglebone-black-adc/ I am
>>> now able to reader a buffer from the different channel.
>>> However I have 2 majors questions that remains:
>>>
>>> 1) I only want to use on channel, then I do not want the ADC to sample
>>> the other one so that i'll have the maximum sampling rate. What is the best
>>> way to disable the channel? If I do not enable them in iio_generic_buffer.c
>>> I am not sure that the ADC is not going to sample this channel or not
>>> (well, I think it wont sample but I prefer to be sure). Is it preferable to
>>> not mention them on the devicetree so that Linux wont know that there are
>>> multiple channels on the ADC? This part is not very clear for me.
>>>
>>> 2) To change the sample frequency of the ADC you mentioned that it is
>>> done using the device tree however I did not find any argument on the ADC
>>> devicetree to change the sampling frequency. I read the discussion you had
>>> on this post (https://patchwork.kernel.org/patch/9391487/ ) but it is
>>> not clear if the frequency setting is done using the kernel module or
>>> devicetrees. Could you explain me this please?
>>>
>>> Looking at this a little more, there is a mistake in the ADC DT file
>>> BB-ADC-0A00.dts. The maximum averaging is 16, not 0x16.
>>>
>>> The line
>>> ti,chan-step-avg = <0x16 0x16 0x16 0x16 0x16 0x16 0x16 0x16>
>>>
>>> should be changed to
>>> ti,chan-step-avg = <16 16 16 16 16 16 16 16>
>>> Fortunately, the driver does a range check and sets the value to 16.
>>>
>>> ti,chan-step-avg = <1 1 1 1 1 1 1 1> /* 2 sample average */
>>> ti,chan-step-opendelay = <0 0 0 0 0 0 0 0>
>>> ti,chan-step-sampledelay = <0 0 0 0 0 0 0 0>
>>>
>>> To achieve a conversion rate of 800 KS/s
>>>
>>> From ti_am335x_tscad.c, 1 + (1 + 13) * 2 = 30 cycles
>>>
>>> The ADC uses a 24 MHz clock, so 1/24,000,000 * 15 = 800 KS/s
>>>
>>> You could increase the sampling rate to 1.6MS/s by changing the average
>>> to 0, which means there is no averaging. To achieve this, the minimum
>>> number of cycles for a conversion is 15 (12.3.7 of the AM3358 Technical
>>> Reference Manual)
>>>
>>> 1 + (1 + 13) * 1 = 15 cycles
>>>
>>> which will give you 1.6 MS/s
>>>
>>> Regards,
>>> John
>>>
>>>
>>> Thanks a lot
>>>
>>> Pierrick
>>>
>>> Le mercredi 28 mars 2018 00:45:01 UTC-4, john3909 a écrit :
>>>>
>>>> Look at the kernel source under tools/iio for examples on how to use
>>>> IIO.
>>>>
>>>> Regards,
>>>> John
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Mar 27, 2018, at 12:10 PM, [email protected] wrote:
>>>>
>>>> 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, [email protected] 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, [email protected] 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 [email protected].
>>>>>> 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 [email protected].
>>>>> 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 [email protected].
>>>> To view this discussion on the web visit
>>>> https://groups.google.com/d/msgid/beagleboard/18b69929-99ca-4e7e-8539-df962a17941d%40googlegroups.com
>>>>
>>>> <https://groups.google.com/d/msgid/beagleboard/18b69929-99ca-4e7e-8539-df962a17941d%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].
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/beagleboard/940610ad-a88c-4918-a3e2-15d7c88d77d1%40googlegroups.com
>>>
>>> <https://groups.google.com/d/msgid/beagleboard/940610ad-a88c-4918-a3e2-15d7c88d77d1%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].
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/beagleboard/ef59523c-02ab-4c58-992a-2b37c0744ff0%40googlegroups.com
>>
>> <https://groups.google.com/d/msgid/beagleboard/ef59523c-02ab-4c58-992a-2b37c0744ff0%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/54c182f4-07cc-4d61-ac1a-6cfd077eec53%40googlegroups.com
>
> <https://groups.google.com/d/msgid/beagleboard/54c182f4-07cc-4d61-ac1a-6cfd077eec53%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
> For more options, visit https://groups.google.com/d/optout.
> <8 average sin1hz 1000sample.png><8 average 20kHz.png>
> <iio_generic_buffer_back.c>
>
>
>
--
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/264ae5d2-5a17-49bc-9ac9-69f7bad39be4%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
