RTOS/am4377: Sigma Delta questions

Part Number: AM4377
Other Parts Discussed in Thread: AMC1204

Tool/software: TI-RTOS

Hi,

I have questions about “Sigma Delta by PRU”.

I'm using AMC1204 in range of +/-250mV.

I received data through the example implemented with PRU.

But I wonder “what value” will be “the maximum value” of the Sigma Delta sensor through the PRU firmware.

Also, I want to know the meaning of the calculation; ((data - 1048576) / 1048576) * 2.5 in Read_ADC_Samples() api as the example.

(PRU-ICSS-Industrial_Drives_01.00.01.00\examples\motor_control\control\foc\foc.c)

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;
}