PRU-ICSS-INDUSTRIAL-SW: AM437x, Sigma Delta Code running in PRU

Peter Wi

Hi,

can somone explain me this code

#ifdef ADC_SDDF

void Read_ADC_Samples(void)
{
    unsigned long u;
    float v;

    u = sd_get_cur_sample(sd, 3); /* SD7 */
    v = ((float)u - 1048576.0) / 1048576.0;
    Data_In[0] = v * 2.5;

    u = sd_get_cur_sample(sd, 2); /* SD6 */
    v = ((float)u - 1048576.0) / 1048576.0;
    Data_In[1] = v * 2.5;
}
#else /* ADC_SDDF */

Why is sd_get_cur_sample(sd, 3) SD7 ?

Why is sd_get_cur_sample(sd, 2) SD6 ?

why calculation for variable v?

Why a multiplication with 2.5 ?

Any more documentation available ?

Thank you

over 1 year ago

0 Nick Saulnier over 1 year ago

TI__Guru 62880 points

Hello Peter,

What file is this snippet from? Where did you get the file?

Regards,

Nick

0 Peter Wi over 1 year ago in reply to Nick Saulnier

Intellectual 810 points

Hi Nick,

it is from the PRU-ICSS-Industrial_Drives_01.00.02.03

filename: foc.c

0 Nick Saulnier over 1 year ago in reply to Peter Wi

TI__Guru 62880 points

Hello Peter,

I am reassigning your thread to our PRU Industrial Drives owner.

Note that support may be limited - that code is several years old, and I am not sure whether it was intended to be modified, or whether it was meant to be run as a black box (i.e., running the code as-is and only documenting the inputs and outputs as opposed to all the coding details within the black box).

Regards,

Nick

0 Peter Wi over 1 year ago in reply to Nick Saulnier

Intellectual 810 points

Hi Nick,

we want to use Sigma Delta and we want to run them in PRU.

Application is motor drive.

It's all a bit magic and i am looking for code, examples, and what to be

done by my side.

I also noticed that the code is old, but couldn't find any newer.

Tthank you.

0 Peter Wi over 1 year ago in reply to Peter Wi

Intellectual 810 points

ok, no support for me ?

Processors

Processors forum

PRU-ICSS-INDUSTRIAL-SW: AM437x, Sigma Delta Code running in PRU