Power Supply; Efr32Bg22 Reset; Push Button And Led - Silicon Laboratories BG22 Explorer Kit User Manual

3.2 Power Supply

The kit is powered by the debug USB cable as illustrated in the figure below.
USB Micro-B
The 5 V power net on the USB bus is regulated down to 3.3 V using an low-dropout regulator (LDO). An automatic isolation circuit
isolates the LDO when the USB cable is not plugged in.
Power can be injected externally on the VMCU net if the USB cable is removed and no other power sources are present on the kit.
Failure to follow this guideline can cause power conflicts and damage the LDO.

3.3 EFR32BG22 Reset

The EFR32BG22 can be reset by a few different sources:
• A user pressing the RESET button.
• The on-board debugger pulling the #RESET pin low.

3.4 Push Button and LED

The kit has one user push button, marked LED0, that is connected to a GPIO on the EFR32BG22. The button is connected to pin PC07
and it is debounced by an RC filter with a time constant of 1 ms. The logic state of the button is high while the button is not being
pressed, and low when the button is pressed.
The kit also features one yellow LED, marked LED0, that is controlled by a GPIO pin on the EFR32BG22. The LED is connected to pin
PA04 in an active-high configuration.
EFR32BG22
PC07 (GPIO.EM4WU8)
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5V0 3V3
IN OUT
LDO
Figure 3.2. BG22 Explorer Kit Power Topology
EFR32_BUTTON0
EFR32_LED0
PA04 (GPIO)
Figure 3.3. Button and LED
Automatic
Isolation
VMCU
Peripherals
EFR32BG22
Wireless SoC
Peripherals
Button & LED
UG509: BG22 Explorer Kit User's Guide
Hardware
User
Rev. 1.1 | 8