ADC Battery monitoring

[Venu_M]

Hello NXP team,

we are working with S32K342 microcontroller - 172 pins

1.While debugging ADC0 instance - PTA1_ADC0-S9 channel (voltage monitoring) is not giving the constant value its fluctuating in the result register ( with fixed voltage value in the power supply).
Ex: 12V fixed RPS getting as 9v,10v,11v,12V,13V.

what is the reason for fluctuating results?

2.ADC1 instance - PTA12_ADC1_P0 channel(Power switch) is giving the value but not expected value from the register.
It is connected to the ref voltage with 3.3V but the converted results are not matching with calculated. We are observing

3.I have configured 14 channel and able to see remaining channel values are as expected, what is wrong in reading the fluctuation values for these 2 pins/channels.

Can you please help us to resolve this issue.

Regards,

Venu

[Venu_M]

Hello Nxp team,

We are using the ADC standard channel for our project.

If we use the standard channel while run time the value are fluctuating continuously.
The actual code like this (Plugins-->Port-->Siul2_Port_Ip.h)
 #define  DCM_DCMRWF4_ADC_INTERLEAVE_MASK     (uint32)0x0000067EUL

So we changed as 0 for the particular bit position which one we are using as standard channel, then the fluctuating is not happening.

Which mean its in the MUX mode so we disabled that manually.

Can you please give the solution on this further.

[_Leo_]

Hi,

Thank you so much for your interest in our products and for using our community.

The ADC is an analog peripheral with intrinsic linearity errors. The AN13413 explains how to read our spec, understand sources of error and describe best practices to increase measurement’s accuracy. There is no calibration magic that will give you an ideal transfer function. It is normal to see a performance difference between ADC channels, they have a different path to the SAR ADC. Some of them are multiplex with digital functions.

Hope it helps you.

Have a nice day!

[Venu_M]

Hello NXP Tech Support team,

            For  ADC mux-mode channels , how to use (ADC0 S8 and ADC0 S9) .For this channel how it will taking ADC0 S8 -->0: GPIO PAD0 (default),1: GPIO PAD45,ADC0 S9--> 0: GPIO PAD1 (default),1: GPIO PAD46.

          Because while flashing DCMRWF4 in this register it's taking the value as 1 so its fluctuating .If I change the register value manually as "1" to "0" there is no fluctuation . (MUX_MODE_EN_ADC0_S8 and MUX_MODE_EN_ADC0_S9).

         Where I need to change this MUX_PAD to default PAD.

         Can you please help to resolve this issue ASAP.

Thanks,

Venu