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2.6
Easy Kit Power Supply concept
The Easy Kit USB Power Supply concept enables the user to work with the Kit without an external Power Supply.
If the USB power supply is not sufficient an additional regulated DC power supply can be used.
Figure 4
Easy Kit Power Supply concept
By means of the Power Supply Jumper X502, USB, or the external power Supply can be selected to run the Easy
Kit. The Setup for the Jumper X502 is shown in
Table 5
Power Supply Jumper configuration
Name in
Configuration
schematic
X502
X502
The USB specification provides a 5 V supply on a single wire from which connected USB devices may draw power.
The specification provides for no more than 5.25 V and no less than 4.35 V between the +ve and -ve bus power
lines.
Initially, a device is only allowed to draw 100 mA. It may request more current from the upstream device in units
of 100 mA up to a maximum of 500 mA. In practice, most ports will deliver the full 500 mA or more before shutting
down power, even if the device hasn't requested it or even identified itself. If a (compliant) device requires more
power than is available, then it cannot operate until the user changes the network (either by rearranging USB
connections or by adding external power) to supply the required power.
Note: If the USB power supply is not sufficient, an external power supply is needed and the Jumper X502 setting
need to be changed.
Note: In case the USB Host PC goes into Suspend Mode, an external Power Supply should be used.
Hardware Manual
Hardware Manual XE166 Easy Kit Board Version 3.1
XE166
CPU
1
X502
USB Supply
5V
Table 5
1
2
3
1
2
3
11
General Information about XE166 Easy Kit Board
Power
LED
5V
DC
Power Supply
6 ... 12V
below.
Description
Power Supply via USB Interface
(Default)
Power Supply via Power Plug
V1.2, 2009-08
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