S32K312 Power Supply ADC Reading via ANAMUX Configuring Not working

[varunbharti]

Hi,

I am working on a custom board using the NXP S32k312(100-pin). I attempted to read the internal VDD_HV_A Voltage using the ADC0 Channel 50 by configuring the ANAMUX (Analog Multiplexer). However, I am reading "0 (Zero)" on the ADC.

I am using ADC0 to measure other external input channels on my hardware, and they are working fine.

I have referred to the reference manual and configured the DCMRWF1 register as per the reference manual :
1) Enabled SUPPLY_MON_EN
2) Configured SUPPLY_MON_SEL as 0 (for VDD_HV_A)
3) Enabled VSS_LV_ANMUX_EN

The pic below shows the snippet of code that I use to enable supply voltages. I am doing this after enabling ADC0 conversion.

Please suggest what other changes are required to make this work. Any inputs will be of help to me.

Thanks in advance.

[PetrS]

Hi,

try to keep VSS_LV_ANMUX_EN cleared.
To measure  VDD_HV_A_DIV (SUPPLY_MON_SEL as 0) have just VDD_HV_A_VLT_DVDR_EN and SUPPLY_MON_EN set, then measure ADC0 Channel 50 as you did.

BR, Petr

[uiulian]

Hi Petr,

SUPPLY_MON_SEL = 0, 1, 2
SUPPLY_MON_EN = 1
VDD_HV_A_VLT_DVDR_EN = 1
VDD_HV_B_VLT_DVDR_EN = 1
VDD_1_5_VLT_DVDR_EN = 1

No correct values available and the fluctuation is high.

for SUPPLY_MON_SEL = 3 to 7, the values are correct.
do you have an idea?
Thank you!