3.
Xplained Mini
Xplained Mini is an evaluation platform that provides a set of small boards with access to all
microcontroller I/Os. The platform consists of a series of low-pin-count Microcontroller (MCU) boards,
which are integrated with Atmel Studio to present relevant user guides, application notes, datasheets,
and example code. The platform also features a Virtual COM port for serial communication to a host PC.
3.1
Mini Embedded Debugger
The ATmega168PB Xplained Mini contains the Mini Embedded Debugger (mEDBG) for on-board
programming and debugging. The mEDBG is a composite USB device of two interfaces; a debugger and
a Virtual COM Port.
Together with Atmel Studio, the mEDBG debugger interface can program and debug the ATmega168PB.
On ATmega168PB Xplained Mini, the ISP/dW interface is connected between the mEDBG and the
ATmega168PB.
The Virtual COM Port is connected to a UART on the ATmega168PB and provides an easy way to
communicate with the target application through the terminal software. It offers variable baud rate, parity,
and stop bit settings.
Note:
The settings on the ATmega168PB must match the settings given in the terminal software.
Info:
The virtual COM port in the mEDBG requires the terminal software to set the data
terminal ready (DTR) signal to enable the UART pins connected to the ATmega168PB. If the
DTR signal is not enabled the UART pins on the mEDBG are kept in high-z (tri-state) rendering
the COM port unusable. The DTR signal is automatically set by some terminal software, but it
may have to be manually enabled in your terminal.
The mEDBG controls one status LED on the ATmega168PB Xplained Mini. The table below shows how
the LED is controlled in different operation modes.
Table 3-1. mEDBG LED Control
Operation mode
Status LED
Power up
LED is briefly lit
Normal operation
LED is not lit
Programming
Activity indicator; the LED flashes when
programming/debugging with the mEDBG
3.1.1
Xplained Mini Clock Output
The mEDBG outputs its CPU clock on a pin. This clock pin is connected to the ATmega168PB clock input
and is used to have a synchronous clock with the mEDBG to enable debugging through debugWIRE.
To disconnect the external clock to the ATmega168PB a 0Ω resistor or strap has to be removed from the
footprint, as shown in the figure below (R109).
ATmega168PB Xplained Mini
©
2017 Microchip Technology Inc.
User Guide
DS50002636A-page 11
