User Manual

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expansion headers, so capes that require the 5V rail to supply the cape direct, bypassing
the TPS65217C , will not have that rail available for use. The 5VDC supply from the USB
port is provided on the SYS_5V, the one that comes from the TPS65217C , rail of the
expansion header for use by a cape. Figure 24 is the connection of the USB power
input on the PMIC.
Figure 24 USB Power Connections
6.1.4 Power Selection
The selection of either the 5VDC or the USB as the power source is handled internally to
the TPS65217C and automatically switches to 5VDC power if both are connected. SW
can change the power configuration via the I2C interface from the processor. In addition,
the SW can read the TPS65217C and determine if the board is running on the 5VDC
input or the USB input. This can be beneficial to know the capability of the board to supply
current for things like operating frequency and expansion cards.
It is possible to power the board from the USB input and then connect the DC power
supply. The board will switch over automatically to the DC input.