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VBAT Connection?

Question asked by jones.bob on May 22, 2011
Latest reply on May 23, 2011 by Donald Becker

The VL Manual (UM0919) says that by default solder bridge (SB1 VBAT) is factory set to be off. This should allow you to connect a battery to the board and run the real time clock when then board is powered off. There should be no connection to the MCU VDD supply from the battery.

When I connect a coin cell to the VBAT connector and GND and then disconnect USB power the board continues to run. If I look at the board carefully there is a component bridging the SB1 pads. Its too small to see what it is though.

Is this behaviour correct?

Do I have to detect that I'm on battery power and select a low power mode?

I'm a bit confused... (Nothing new).....