Figure 4-2. Power Supply Block Diagram
Power source
Power switch
Power converter
Power consumer
External input
5V
mEDBG USB
Regulator 3.3V
Input select
jumper
0R
VCC_P5V0
Target select
jumper
0R
mEDBG
&
Target
VCC_P5V0
VCC_P3V3
The input voltage select jumper (J300, 3-pin header footprint) can be soldered in to select between power
from the USB port or from the VIN pin on the Arduino power header footprint. By default, the selector is
bypassed with a 0Ω resistor (R300) to connect the USB voltage to the on-board 3.3V/150mA regulator
and target voltage select header.
The target voltage select jumper (J301, 3-pin header footprint) can be soldered in to select between the
on-board 3.3V regulator or the voltage from the input voltage select jumper (J300). The selector is
bypassed with a 0Ω resistor (R301) to connect the kit input voltage to the ATmega168PB and mEDBG.
Important:
If the target voltage and input voltage select headers are soldered in and used with
a jumper, the bypass 0Ω resistors have to be removed to avoid contention.
4.2
Board Assembly
The Xplained Mini board can easily be assembled into a product prototype for software development and
hardware verification. All signals of the ATmega168PB are available in the Xplained Mini board connector
grid, enabling easy connection of external sensors and output devices in order to prototype the customer
specific application.
4.2.1
Connecting an Arduino Shield
Arduino
®
shields can be mounted in the marked positions (J200, J201, J202, J203, and J204).
Warning:
The ATmega168PB Xplained Mini connects VCC_TARGET to the Arduino SPI
connector, while all Arduino boards connect VCC_P5V0 to the same pin. The VCC_TARGET
may be either 3.3V or 5.0V depending on the configuration of the kit if the kit is configured for
3.3V operation. Connecting an Arduino shield may damage the board permanently. It is not
recommended to solder the SPI connector when using Arduino shields if not strictly necessary.
If the connector is required it is recommended to remove pin two from the SPI connector.
4.3
Target Headers and Connectors
4.3.1
Target Digital I/O
The J200 and J201 headers provide access to the ATmega168PB digital I/O pins.
ATmega168PB Xplained Mini
©
2017 Microchip Technology Inc.
User Guide
DS50002636A-page 17
