Reading adc values problem

Naven

Intellectual 750 points

hi ,

am New in ADC working in Beagel Bone Black board & SDK7,

when reading all channels the data will come different manner

reading channel data through dev node ,

any body working this please reply me .

i/p voltage :1 v

o/p :ch0 - 3865 , ch1 - 47,ch2 - 49,ch3 -57,ch4 - 1907,ch5 - 2562 ,ch6 - 3352, ch7-3792.(default voltage )

Registers Configuration :

idle = ioread32(base_addr + ADCSTAT);   //check ideal status or not
while(idle & (1<<5)) ;

clk_div = 0x40;
iowrite32(clk_div, base_addr + ADC_CLKDIV);    //divide input ADC clock by 8 24M ,(32+1 )

cntl = ioread32(base_addr + CTRL);
cntl = cntl | (1 << 1);         //TSC ADC tags
cntl = cntl | (1 << 2);         //disable write protect
cntl = cntl | (1 << 5);         //AFE_PENCTRL
cntl = cntl | (1 << 6);         //AFE_PENCTRL
cntl = cntl | (1 << 7);         //Transistor bias
iowrite32(cntl,base_addr + CTRL);

stpcnfg = stpcnfg |(1 << 6);            // XPPSW_SWC
stpcnfg = stpcnfg |(1 << 8);            //XNNSW_SWC
stpcnfg = stpcnfg |(1 << 10);
stpcnfg = stpcnfg |(3 << 19);           // Channels changes
stpcnfg = stpcnfg |(4 << 2);            // average 16 samples
iowrite32(stpcnfg,base_addr + STEPCONFIG1);     //stepconfig reg 1


stepen = stepen |(1 << 1);                 //enable 1 stepconfig register
stepen = stepen |(1 << 2);                 //enabled 2 stepconfig register/
iowrite32(stepen,base_addr + STEPENABLE);

adcs = ioread32(base_addr + CTRL);
adcs= adcs |(1 << 0);                 //Enable TSC_ADC_SS/
iowrite32(adcs,base_addr + CTRL);

data = ioread32(base_addr + FIF0DATA); //FIFO0_data
val = copy_to_user(buf,&data,4);
printk("FIF0_DATA = %d\n",(data&0xFFF));

Thanks & Regards,

Naveen,

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

I will forward this to the SW team.

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

Intellectual 750 points

its k sir thank u

0 Yordan Kovachev over 10 years ago in reply to Naven

TI__Guru**** 161600 points

Hi Naveen,

If you want to capture data from user space, you need to follow the configurations here:

Have you ensured that you've enabled all channels accordingly: Mode of operation, Channels used, etc... ?

Also you can use the sample application: & the documentation in drivers/staging/iio/Documentation to better understand the function of the adc in AM335x devices.

Best Regards,

Yordan

0 Naven over 10 years ago in reply to Yordan Kovachev

Intellectual 750 points

This user guide for sysfs reading but iam reading data through device node it created my own driver ,
problem with some register settings ,check once my register settings any problem in my code plz reply me.

Naven

0 Yordan Kovachev over 10 years ago in reply to Naven

TI__Guru**** 161600 points

Hi Naven,

So your problem is that kernel doesn't output any values? or is it something else?

As I see you get some default output on your console:

"o/p :ch0 - 3865 , ch1 - 47,ch2 - 49,ch3 -57,ch4 - 1907,ch5 - 2562 ,ch6 - 3352, ch7-3792.(default voltage )"

But this should be expected, as driver is initialized at an early stage, before there is any action on the touch display.

Best Regards,

Yordan

0 Naven over 10 years ago in reply to Yordan Kovachev

Intellectual 750 points

Hi Yordan,

The channel 7[AIN7] value is correct 3792 ,VDD input vlotage given this pin so expected value is correct,

but my problem is channel 6[AIN6] also will get 3352 the pin is open ,so how i get this value without any input ???

and ch0 also same behavior. so please check once register settings any mistake in that code once reply me,

thank u so much for reply..

Regards,

Naveen.

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Reading adc values problem