NRF51822 LiPo Voltage Reading

[Teecup]

Hi! I am trying to read the voltage of a LiPo battery as explained in this blog post. The code on github however, is not compatible with the latest SDK for the SOC (12.3). Does anybody have an upgraded version or knows which function calls to swap? It is only a few lines of code so I hope somebody could help me with that.

Thank you!

[Einar Thorsrud]

Hi,

We do not have a update of the github example, but you can refer to the ADC example in SDK 12.3.

The important point is anyway the schematics in the blog post, showing how you use a resistor network to charge a capacitor (with high resistance resistors to reduce the current leakage). In turn, this capacitor charges the internal capacitor of the ADC during sampling. If this was not present, charging the internal capacitance would increase the current draw from the battery, pulling down the voltage, so the measurement would be incorrect. The ADC sampling code itself is straightforward.

[Teecup]

Thank you for response! I have the schematics transferred to a simple breadboard and tried to copy the ADC sample code from SDK12.3, but somehow my app gets stuck on nrf_drv_adc_buffer_convert. I am using P01 to connect the ADC and use it with NRF_DRV_ADC_DEFAULT_CHANNEL(NRF_ADC_CONFIG_INPUT_2). What could be wrong here with the code?

[awneil]

Teecup said:

tried to copy the ADC sample code

Have you tried just using the example  unmodified to start with, and to gain an understanding of how it works?

Teecup said:

somehow my app gets stuck

Use the debugger to find out where, exactly, it is getting stuck.

Compare what happens in your code to what happens in the unmodified example ...