Is it OK to power the board with a 3.6v coin battery?
As long as your battery never exceeds 3.6 volts, that would be fine but double check the battery before connecting. Sometimes a fully charged battery will be higher than it’s rated voltage.
Here’s additional information about powering the Edge with the coin cell holder:
I am using a 3.6V coin battery right now. I find that the voltage between VDD and GND on the board drops rapidly from 2.5 to 2.4, 2.3, 2.2, 2.0, 1.9V and my application stops working in 10 seconds.
I suspect that the ADC and mic on the board cost a lot of power and they stop working after the voltage drops below 2.2 V. Only the LEDs can work but becomes much dimmer.
What is the required voltage and power to make the ADC and mic work? Is there any problem with my board?
@mobvoi, the audio signal chain is designed to operate at 2V because that’s the range of the Apollo3 ADC. Below 2V on VDD will reduce the utilization of the ADC’s range.
How quickly does the voltage drop? Have you tried this test with a fresh battery?
Yes, a new battery was used.
After switching to a new board, the problems disappear! The old board is from the tensorflow dev summit.
Are there any changes to the board after the summit?