It is my understanding that ARDUINO 101 board has an RTC.
How do we connect a battery to keep it working?
Hi, taking a look at the schematic and the library code, it appears that the 32 kHz RTC clock/counter is powered from the Curie's AON_IO_VCC rail shown on page 3 of the schematic. AON_IO stands for always on I/O. This pin is connected to the VDD_PLAT_3P3 rail that comes from the linear regulator. The linear regulator gets power from either the USB connector or the DC jack. In principle, you could connect a battery to the DC jack, but run time will be short. For example, a 9 V alkaline battery would only last ~4 hours connected to the DC jack. The Arduino 101 wasn't designed for RTC, or more generally, battery powered applications. To be clear, the Curie might work in a battery application, but the Arduino implementation is not suitable.
ljardo:
To be clear, the Curie might work in a battery application, but the Arduino implementation is not suitable.
I think that's an important distinction - Arduino 101 is just one possible hardware/firmware/software implementation of Curie.