i'm using a custom curie bsp board it is having a battery charger BQ25120, now i'm flashing using usb cable ,i need to connect to a coin cell battery how to connect ???
Let me try to help you.
By "how to connect?" do you mean the necessary specifications of the battery that you're going to be using? That information can be found here https://www.intel.com/content/dam/support/us/en/documents/boardsandkits/curie/intel-curie-module-dat... https://www.intel.com/content/dam/support/us/en/documents/boardsandkits/curie/intel-curie-module-dat..., the Intel Curie datasheet.
On Section 2, Specifications, you can find the operating voltages for the module. Take a look at table 2-2.
Also, check for section 3.4.4 in the Intel Curie Module Design Guide, https://www.intel.com/content/dam/support/us/en/documents/boardsandkits/curie/intel-curie-module-des... https://www.intel.com/content/dam/support/us/en/documents/boardsandkits/curie/intel-curie-module-des....