Remember:
Keep the debugger’s firmware up-to-date. Firmware upgrades automatically when using
MPLAB
®
X IDE.
3.1.2
Virtual Serial Port (CDC)
The virtual serial port (CDC) is a general purpose serial bridge between a host PC and a target device.
3.1.2.1
Overview
The on-board debugger implements a composite USB device that includes a standard Communications Device Class
(CDC) interface, which appears on the host as a virtual serial port. The CDC can be used to stream arbitrary data
in both directions between the host computer and the target: All characters sent through the virtual serial port on the
host computer will be transmitted as UART on the debugger’s CDC TX pin, and UART characters captured on the
debugger’s CDC RX pin will be returned to the host computer through the virtual serial port.
Figure 3-1. CDC Connection
Target MCU
UART TX
UART RX
Debugger
USB
CDC RX
CDC TX
PC
Terminal
Software
Target
Receive
Target
Send
Terminal
Receive
Terminal
Send
Info:
, the debugger’s CDC TX pin is connected to a UART RX pin on the target
for receiving characters from the host computer. Similarly, the debugger’s CDC RX pin is connected to a
UART TX pin on the target for transmitting characters to the host computer.
3.1.2.2
Operating System Support
On Windows
®
machines, the CDC will enumerate as
Curiosity Virtual COM Port
and appear in the Ports section of
the Windows Device Manager. The COM port number can also be found there.
Info:
On older Windows systems, the CDC requires a USB. This driver is included in installations of
MPLAB
®
X IDE.
On Linux
®
machines, the CDC will enumerate and appear as
/dev/ttyACM#
.
Info:
tty* devices belong to the “dialout” group in Linux, so it may be necessary to become a member of
that group to have permissions to access the CDC.
On Mac
®
machines, the CDC will enumerate and appear as
/dev/tty.usbmodem#
. Depending on which terminal
program is used, it will appear in the available list of modems as
usbmodem#
.
Curiosity Nano
©
2021 Microchip Technology Inc.
User Guide
50003124A-page 8
