Power Distribution

SAM V71 Xplained Ultra has four power sources as described in Power Sources. Figure 1 shows a block diagram of the power supply circuitry, the related I/O pins are described in Table 1.

The kit can be powered from the EDBG USB, Target USB, external 5.0V, and/or a 5-14V DC jack input. The kit will automatically select a source to draw power from.

An on board supercap (100mF) is charged to 3.6V from the kits 5V net. When all external power is removed from the board or the 3.3V regulator is disabled by the application running on the ATSAMV71Q21 the power switch will supply the ATSAMV71Q21 from the supercap. It is intended that the supercap can supply the ATSAMV71Q21 in its low power backup mode.

Info: When the on-board regulator is turned off by the target application in the ATSAMV71Q21, all ICs on the kit are unpowered except the ATSAMV71Q21. Care must be taken to not supply and stray power these ICs through the ATSAMV71Q21s I/O pins.
Figure 1. Power Supply Block Diagram
Table 1. Power Distribution Signals
SAM V71 pin Function Description
PC17 GPIO Power Enable, drive low to disable the on-board voltage regulator
PA01 WKUP1 Regulator Power Detect, pulled high when the regulator output is good
PC16 GPIO Drive low to enable the kit to supply the target USB