Xplained Mini; Mini Embedded Debugger - Microchip Technology ATmega328P Xplained Mini Manual

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 ATmega328P 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 ATmega328P. On
ATmega328P Xplained Mini, the ISP/dW interface is connected between the mEDBG and the ATmega328P.
The virtual COM port is connected to a UART on the ATmega328P 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 ATmega328P 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 ATmega328P. 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 the target
terminal.
The mEDBG controls one status LED on the ATmega328P Xplained Mini. The table below shows how the LED is
controlled in different operation modes.
Table 3-1. mEDBG LED Control
Power-up
Normal operation
Programming
3.1.1 Xplained Mini Clock Output
The mEDBG outputs its CPU clock on a pin. This clock pin is connected to the ATmega328P 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 ATmega328P, a 0Ω resistor or strap has to be removed from the footprint, as
shown in the figure below (R109).
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2020 Microchip Technology Inc.
Operation Mode
ATmega328P Xplained Mini
Status LED
LED is briefly lit
LED is not lit
Activity indicator; the LED flashes when programming/
debugging with the mEDBG
User Guide
Xplained Mini
DS50002659B-page 10