read ADC value (AM437x)

alup nelso

Prodigy 110 points

Hi,

As mentioned in an former post: https://e2e.ti.com/support/arm/sitara_arm/f/791/t/427651

I'm looking for the good way to read the adc value.

Could you please show me a C/C++ example code for reading ADC value continuously and in the fastest way.

Thank you for your rely.

Best Regards,
Alexandre

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Alexandre,

This forum supports only the TI distributed Linux SDK. There is an ADC driver included in the SDK. Diver usage is explained here: http://processors.wiki.ti.com/index.php/Linux_Core_ADC_User's_Guide

0 alup nelso over 10 years ago in reply to Biser Gatchev-XID

Prodigy 110 points

Biser,

It seems that this guide describes the use of the driver for another board (AM335x). Indeed, the sample application does not work on the AM437x (generic_buffer).

Best Regards
Alexandre

0 Biser Gatchev-XID over 10 years ago in reply to alup nelso

TI__Guru**** 393215 points

AM437X ADC0 is identical to AM335X ADC.

0 alup nelso over 10 years ago in reply to Biser Gatchev-XID

Prodigy 110 points

why I don't have this file : /sys/bus/iio/devices/iio\:device0/buffer/ ?
which is necessary to run the sample application.

Best Regards
Alexandre

0 Biser Gatchev-XID over 10 years ago in reply to alup nelso

TI__Guru**** 393215 points

I have asked the SW team to check this.

0 alup nelso over 10 years ago in reply to Biser Gatchev-XID

Prodigy 110 points

thank you.

Best Regards
Alexandre

0 Yordan Kovachev over 10 years ago in reply to alup nelso

TI__Guru**** 161600 points

Hi Alexandre,

Which SDK are you running?
I just tried this on my AM437x GP EVM, running SDK1.0 (kernel 3.14) and the directory /sys/bus/iio/devices/iio\:device0/buffer/ exists.
Also commands from the wiki pointed by Biser are functional.

Best Regards,
Yordan

0 Yordan Kovachev over 10 years ago in reply to Yordan Kovachev

TI__Guru**** 161600 points

From the related thread, I see that you use kernel 3.12, so I guess you use SDK7.0, right?

0 alup nelso over 10 years ago in reply to Yordan Kovachev

Prodigy 110 points

Hi Yordan,

I put the preinstalled linux of the " ti-processor-sdk-linux-am437x-evm-01.00.00.00-Linux-x86-Install.bin" package to a SD card and now I have the right files (as /sys/bus/iio/devices/iio\:device0/buffer/ ) .
The version where the files were missing was that shipped with the card.

Best Regards,
Alexandre

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read ADC value (AM437x)