why ADC fails working?

miles zhang

Prodigy 40 points

dear,

my work is to make ADC work in 8 general purpose ADC channels,but fail.

I have done according to tips in the AM335x ADC Driver's Guide, and the link is below:

http://processors.wiki.ti.com/index.php/AM335x_ADC_Driver's_Guide

unfortunately, debug result is beyond my mind. the debug steps and results is below.

1, I have started ADC driver ti_adc.ko and find the director of "sys/bus/iio:device/in_voltage4_raw ...." , and the operation is successful to "sys/bus/iio:device/scan_elements/in_voltage4_en" and "sys/../mode" and so on .

the display of director is below:

buffer in_voltage2_raw in_voltage6_raw power
dev in_voltage3_raw in_voltage7_raw scan_elements
in_voltage0_raw in_voltage4_raw mode subsystem
in_voltage1_raw in_voltage5_raw name uevent

it seems that the ADC driver ti_adc.ko run ok.

then I run the APP /usr/generic_buffer -n tiadc -l 256 -c 3.

it spits out information like this:

iio device number being used is 0

Failed to find the trigger tiadc-dev0

what happens to this ? ths.

over 12 years ago

0 bharatgohil over 12 years ago

Intellectual 475 points

Hi,

Same problem.Have you find the solution???

Regards,

Bharat Gohil

0 shishu yang over 11 years ago in reply to bharatgohil

Prodigy 180 points

please refer to the ADC driver guide on wiki.

Notice this message:" Since our driver is not trigger based we need to modify this application to bypass the trigger detection. Please apply patch Media:Generic_buffer.patch on top of the application generic_buffer.c in order to bypass the trigger conditions. " .

Click the link Media:Generic_buffer.patch ,and you can find how to modify the test file.The '-'means remove the row,and the '+'means add code on the row.

0 miles zhang over 11 years ago in reply to bharatgohil

Prodigy 40 points

finally I find that there is something wrong with the electric circuit.

0 xixiguohx over 10 years ago in reply to shishu yang

Intellectual 720 points

Hi shishu yang,

I have modified the generic_buffer.c acording to the link, but I get new error:

root@ /xhan$ ./generic_buffer -n tiadc -l 256 -c 3
iio device number being used is 0
/sys/bus/iio/devices/iio:device0
Failed to open /dev/iio:device0

root@ /xhan$ ./generic_buffer -n tiadc -l 256 -c 3
iio device number being used is 0
/sys/bus/iio/dev[ 4777.462707] iio-buffer, current state requested again
ices/iio:device0
Failed to open /dev/iio:device0

Do you know what's wrong with it?

I find that under /dev, there is not iio:device0. But in config, I use

<*>   TI's ADC drive
not

<M>   TI's ADC driver
Why there not creat iio:device0 under /dev?

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why ADC fails working?