SMART ARM-based Microcontrollers

4.2.5 Backup Battery

The SAM L21 Xplained Pro has a backup battery for use with the SAM L21 backup module. The battery can be connected to the device by placing a jumper over pin 1-2 on the 3-pin VBAT SELECT header.

By default the jumper is placed over pin 2-3 to select the board power supply. This configuration is selected to avoid draining the battery and can be used during development.

Table 4-12. VBAT SELECT Header
VBAT SELECT pin	Function
1	Power from battery
2	PB03/VBAT pin on SAM L21
3	Power from board supply

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