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
the target 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.
| 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 |