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 1. mEDBG LED ControlOperation 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 |