Curiosity Nano; On-Board Nano Debugger - Microchip Technology SAM D21 User Manual

3.

Curiosity Nano

Curiosity Nano is an evaluation platform that provides a set of small boards with access to most of the microcontroller
I/Os. The platform consists of a series of low pin-count microcontroller (MCU) boards, which are integrated with
MPLAB X IDE to present relevant user guides, application notes, data sheets, and example codes. The platform
features a Virtual COM port (CDC) for serial communication to a host PC and a Data Gateway Interface (DGI) GPIO.
3.1

On-Board Nano Debugger

The SAM D21 Curiosity Nano contains an On-Board Nano Debugger for programming and debugging. The On-Board
Nano Debugger is a complex USB device consists of several interfaces, such as a debugger, a mass storage device,
a data gateway, and a Virtual COM port (CDC). Together with MPLAB X IDE, the On-Board Nano Debugger interface
can program and debug SAMD21G17D. An 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 SAMD21G17D and it provides an easy way to communicate with the target
application through terminal software. The On-Board Nano Debugger controls one Power/Status LED (marked PS)
on the SAM D21 Curiosity Nano evaluation board. The following table describes how the LED is controlled in different
operation modes.
Table 3-1. On-Board Nano Debugger LED Control
Operation Mode
Boot Loader mode LED blink at 1 Hz during power up.
Power-up
Normal operation
Programming
Fault
Sleep/Off
3.1.1 Virtual COM Port
A general-purpose USB serial bridge between a host PC and a target device.
3.1.1.1 Overview
The debugger implements a complex USB device that includes a standard Communications Device Class (CDC)
interface, which appears on the host as a Virtual COM Port. The CDC can be used to stream arbitrary data in both
directions between the host and the target. Characters sent from the host will appear in UART form on the CDC TX
pin, and UART characters sent into the CDC RX pin will be sent back to the host. On Windows machines, the CDC
will enumerate as the Curiosity Virtual COM Port and appear in the ports section of the device manager. The COM
port number is usually shown here.
Note: On the older version of Windows systems a USB driver is required for CDC. This driver is included in Atmel
Studio and MPLAB X IDE installations. On Linux machines, the CDC will enumerate and appear as /dev/ttyACM#.
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#.
3.1.1.2 Limitations
Not all UART features are implemented in the debugger CDC, and the constraints are outlined below:
• Baud rate: Must be in the range of 1200 bps to 500 kbps. Values outside this range will be capped to these
values, without warning. Baud rate can be changed on-the-fly.
• Character format: Only 8-bit characters are supported.
• Parity: Can be odd, even, or none.
• Hardware flow control: Not supported.
©
2020 Microchip Technology Inc.
Arrow.com. Arrow.com. Arrow.com. Arrow.com. Arrow.com.
Downloaded from Downloaded from Downloaded from Downloaded from Downloaded from
Status LED
LED is lit, constant.
LED is lit, constant.
Activity indicator, the LED flashes slowly during programming or debugging.
The LED flashes fast if a power fault is detected.
LED is OFF. The On-Board Nano Debugger is either in Sleep mode or Power-Down mode. This
will occur only if the kit is externally powered
User Guide
SAM D21
Curiosity Nano
®
DS70005409C-page 5