ATmega4809 Curiosity Nano contains an onboard debugger for programming and debugging. The onboard debugger is a composite USB device of several interfaces: a debugger, a mass storage device, a data gateway, and a Virtual COM port (CDC).
Together with Atmel Studio/Microchip MPLAB® X, the onboard debugger interface can program and debug the ATmega4809.
A Data Gateway Interface (DGI) is available for use with the logic analyzer channels for code instrumentation, to visualize program flow. DGI GPIOs can be graphed using the Data Visualizer.
The Virtual COM port is connected to a UART on the ATmega4809 and provides an easy way to communicate with the target application through terminal software.
The onboard debugger controls one Power and Status LED (marked PS) on the ATmega4809 Curiosity Nano board. The table below shows how the LED is controlled in different operation modes.
| Operation Mode | Status LED |
|---|---|
| Boot loader mode | LED blink at 1 Hz during power up. |
| Power-up | LED is lit - constant. |
| Normal operation | LED is lit - constant. |
| Programming | Activity indicator; the LED flashes slowly during programming/debugging. |
| Fault | The LED flashes fast if a power fault is detected. |
| Sleep/Off | LED is off. The onboard debugger is either in Sleep mode or powered down. This can occur if the kit is externally powered. |