Is enable required before configuration? Does toggling NRF_ADC->ENABLE reset the configuration (like it does for the radio?) Is the power to the ADC automatic, so that even if enabled, it might be quiescent current?
The product spec, register description for NRC_ADC->ENABLE is a tautology: "Enabled" in one column equals "Enabled" in another column. The second column should describe what enabled means.
Somewhere I read that enable means "acquire the configured input channel". Do you need to enable ADC (to acquire input channel) if input selection is disabled? Before every read?
The sequence of calls that I am using is: enable; spinOnNotBusy; config; clearEndEvent; start; spinOnEndEvent; read; clearEndEvent; start; spinOnEndEvent; .... (not using PPI or interrupts or SD, just occasionally reading Vcc/3 with ref VBG.)
Another thread said a 1ms delay was necessary.
For me, it always reads zero.