SLWSTK6061A Datasheet, PDF (12/32 Pages) Silicon Laboratories – UG182: EFR32 Flex Gecko 2400/868 MHz Wireless Starter Kit

UG182: EFR32 Flex Gecko 2400/868 MHz Wireless Starter Kit
Power Supply and Reset
5.2 Board Controller Power
The board controller is responsible for important features such as the debugger and the Advanced Energy Monitor, and is powered
exclusively through the USB port in the top left corner of the board. This part of the kit resides on a separate power domain, so a differ-
ent power source can be selected for the target device while retaining debugging functionality. This power domain is also isolated to
prevent current leakage from the target power domain when power to the Board Controller is removed.
The board controller power domain is exclusively supplied by the J-Link USB cable, and is not influenced by the position of the power
switch.
The kit has been carefully designed to keep the board controller and the target power domains isolated from each other as one of them
powers down. This ensures that the target EFR32 device will continue to operate in the USB and BAT modes.
5.3 EFR32 Reset
The EFR32 Wireless SoC can be reset by a few different sources:
• A user pressing the RESET button.
• The on-board debugger pulling the #RESET pin low.
• An external debugger pulling the #RESET pin low.
In addition to the reset sources mentioned above, the Board Controller will also issue a reset to the EFR32 when booting up. This
means that removing power to the Board Controller (plugging out the J-Link USB cable) will not generate a reset, but plugging the cable
back in will, as the Board Controller boots up.
5.4 Battery Holder
In radio applications with high output power, peak current consumption will exceed the current sourcing capacity of a coin-cell battery.
To support evaluation of the EFR32 Flex Gecko in situations where powering the kit from a wired USB connection is impractical, for
instance during range-tests, the kit is supplied with a battery holder for 2 AA batteries.
To use the battery holder, first set the power switch in the BAT position. Then attach the cable to pin 1 and 2 on the expansion header,
orienting the connector so the black cable cable goes down towards pin 1, and the red cable up towards pin 2.
Put power switch in BAT position
Connect battery holder
to EXP header.
- Pin 2 (up): Red wire
- Pin 1 (down): Black wire
Figure 5.2. Battery Holder Connection
Warning: There is no reverse voltage protection on the VMCU pin! Ensure that the battery holder is connected the right way. Failure to
do so may result in damage to the radio board and its components.
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