2
AVR32913
32113-AVR32-07/08
2 Powering up the board
The EVK1105 offers three interfaces to power the board, from one of the two USB
interfaces or from an external source connected to the header J1. The board can be
powered from 3 different sources, external power supply, “USB VCP” and “USB
USER” connector. If two power sources are applied at the same time the following
priorities are used to select the current valid power source:
1. External power supply (header J1)
2. USB VCP
3. USB USER
That means that if an external power supply is connected to the board it has the
highest priority and will therefore serve as current power supply. Other power
supplies that are connected to the board at the same time will be ignored.
The input range on the external power supply header is from 3.3V to 5V. In order to
be able to supply external USB devices that are connected to the board the minimal
power supply specification should be 5V, 1A. This ensures that the board will work
properly if a USB device is connected that needs the maximum allowed 500mA as
specified in the USB specification. It is not possible to draw that amount of current
from the host through a normal USB cable but there are cables available that can be
connected to two hosts (such a cable is not a kit content).
In order to play music from a mass-storage device it is enough to power the board
from the USB VCP connector. Use the “Mini-B plug to std-A plug 1.5m USB2.0” cable
that is included in the kit and connect it between the host and the board USB VCP
connector.
Figure 2-1
Possible power input interfaces on the EVK1105
