Is the VSS Pin (pin 103) connected internally to GND_Shield?

[Stefan Schmidt]

Dear Nordic Support Team,

 In the datasheet of the nrf9160 (nRF9160_PS_v2.2.pdf) the VSS pin appears in the section 6.4.5.1 GPIO Electrical Specification, but I cannot find the information if it is internally connected to GND_Shield.

Best regards

Stefan

[Øyvind]

Stefan Schmidt said:

now I have to apologize, I have been on vacation last week :-)

No worries! Hope you had a good vacation and able to charge the batteries ;)

Stefan Schmidt said:

Thank you for your reply. I have been using single ended mode, and the idea to use differential mode and connect the negative side to the 'star' ground is actually a good one! I will try this. 

Yes, please test and let me know how that works for you.

Kind regards,

Øyvind

[Stefan Schmidt]

Hi Øyvind,

 I have setup the tiny project on the 9160DK board with one channel single ended, the other channel in differential mode with the negative input connected to ground externally.

Now, that all leaves me a bit unsatisfied. I measure 1.817V with a DMM on VDD_GPIO, but both channels give me the same reading of about 1.696mV:
ADC reading[0]:
- adc@e000, channel 0: 1929 = 1695 mV
- adc@e000, channel 1: 965 = 1696 mV
ADC reading[1]:
- adc@e000, channel 0: 1929 = 1695 mV
- adc@e000, channel 1: 964 = 1694 mV
ADC reading[2]:
- adc@e000, channel 0: 1930 = 1696 mV
- adc@e000, channel 1: 964 = 1694 mV
ADC reading[3]:
- adc@e000, channel 0: 1929 = 1695 mV
- adc@e000, channel 1: 964 = 1694 mV
ADC reading[4]:
- adc@e000, channel 0: 1929 = 1695 mV
- adc@e000, channel 1: 964 = 1694 mV
ADC reading[5]:
- adc@e000, channel 0: 1930 = 1696 mV
- adc@e000, channel 1: 965 = 1696 mV
ADC reading[6]:
- adc@e000, channel 0: 1930 = 1696 mV
- adc@e000, channel 1: 965 = 1696 mV

I 2350.adc.zip

I have attached the zipped zephyr/samples/drivers/adc folder, you can find my nrf9160dk_nrf9160_ns.overlay in boards.

If you find some time, could you please have a look a the program and give me some hints how I could get the reading closer to the 1.8V that I measure with my DMM?

Best regards

Stefan

[Øyvind]

Hi Stefan thanks for sharing. No updates yet. 

Kind regards,
Øyvind