3.1 On-Board Debugger Overview

PIC18F57Q43 Curiosity Nano contains an on-board debugger for programming and debugging. The on-board debugger is a composite USB device consisting of several interfaces:

A debugger that can program and debug the PIC18F57Q43 in MPLAB® X IDE
A mass storage device that allows drag-and-drop programming of the PIC18F57Q43
A virtual serial port (CDC) that is connected to a Universal Asynchronous Receiver/Transmitter (UART) on the PIC18F57Q43, and provides an easy way to communicate with the target application through terminal software
A Data Gateway Interface (DGI) for code instrumentation with logic analyzer channels (debug GPIO) to visualize program flow

The on-board debugger controls a Power and Status LED (marked PS) on the PIC18F57Q43 Curiosity Nano board. The table below shows how the LED is controlled in different operation modes.

Table 3-1. On-Board Debugger LED Control
Operation Mode	Power and Status LED
Boot Loader mode	The LED blinks slowly during power-up
Power-up	The LED is ON
Normal operation	The LED is ON
Programming	Activity indicator: The LED blinks slowly during programming/debugging
Drag-and-drop programming	Success: The LED blinks slowly for 2 sec. Failure: The LED blinks rapidly for 2 sec.
Fault	The LED blinks rapidly if a power fault is detected
Sleep/Off	The LED is OFF. The on-board debugger is either in a sleep mode or powered down. This can occur if the board is externally powered.

Info: Slow blinking is approximately 1 Hz, and rapid blinking is approximately 5 Hz.