Microchip Technology DM320115 Installation manual

ATmega4809 Curiosity Nano
ATmega4809 Curiosity Nano Hardware User Guide
Preface
The ATmega4809 Curiosity Nano Evaluation Kit is a hardware platform to evaluate microcontrollers in the megaAVR®
0-series Family. This board has the ATmega4809 microcontroller (MCU) mounted.
Supported by both MPLAB® X IDE and Atmel Studio 7, the board provides easy access to the features of the
ATmega4809 to explore how to integrate the device into a custom design.
The Curiosity Nano series of evaluation boards include an on-board debugger. No external tools are necessary to
program and debug the ATmega4809.
•MPLAB® X IDE and Atmel Studio - Software to discover, configure, develop, program, and debug Microchip
microcontrollers.
•Code examples in Atmel START - Get started with code examples or generate drivers for a custom
application.
•Code examples on GitHub - Get started with code examples.
•ATmega4809 website - Find documentation, datasheets, sample, and purchase microcontrollers.
•ATmega4809 Curiosity Nano website - Kit information, latest user guide, and design documentation.
© 2020 Microchip Technology Inc. User Guide DS50002804B-page 1

Table of Contents
Preface........................................................................................................................................................... 1
1. Introduction............................................................................................................................................. 4
1.1. Features....................................................................................................................................... 4
1.2. Board Overview............................................................................................................................4
2. Getting Started........................................................................................................................................ 5
2.1. Quick Start....................................................................................................................................5
2.2. Design Documentation and Relevant Links................................................................................. 5
3. Curiosity Nano.........................................................................................................................................7
3.1. On-Board Debugger Overview..................................................................................................... 7
3.2. Curiosity Nano Standard Pinout................................................................................................. 13
3.3. Power Supply............................................................................................................................. 14
3.4. Low-Power Measurement.......................................................................................................... 18
3.5. Programming External Microcontrollers..................................................................................... 19
3.6. Connecting External Debuggers................................................................................................ 22
4. Hardware User Guide........................................................................................................................... 25
4.1. Connectors.................................................................................................................................25
4.2. Peripherals................................................................................................................................. 26
4.3. On-Board Debugger Implementation......................................................................................... 28
5. Hardware Revision History and Known Issues..................................................................................... 29
5.1. Identifying Product ID and Revision........................................................................................... 29
5.2. Revision 8...................................................................................................................................29
5.3. Revision 7...................................................................................................................................29
5.4. Revision 5...................................................................................................................................29
6. Document Revision History...................................................................................................................30
7. Appendix............................................................................................................................................... 31
7.1. Schematic...................................................................................................................................31
7.2. Assembly Drawing......................................................................................................................33
7.3. Curiosity Nano Base for Click boards™...................................................................................... 34
7.4. Disconnecting the On-Board Debugger..................................................................................... 35
7.5. Getting Started with IAR™...........................................................................................................36
The Microchip Website.................................................................................................................................39
Product Change Notification Service............................................................................................................39
Customer Support........................................................................................................................................ 39
Microchip Devices Code Protection Feature................................................................................................ 39
Legal Notice................................................................................................................................................. 40
Trademarks.................................................................................................................................................. 40
ATmega4809 Curiosity Nano
© 2020 Microchip Technology Inc. User Guide DS50002804B-page 2

Quality Management System....................................................................................................................... 41
Worldwide Sales and Service.......................................................................................................................42
ATmega4809 Curiosity Nano
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1. Introduction
1.1 Features
• ATmega4809 Microcontroller
• One Yellow User LED
• One Mechanical User Switch
• Footprint for 32.768 kHz Crystal
• On-Board Debugger:
– Board identification in Microchip MPLAB® X IDE and Atmel Studio 7
– One green power and status LED
– Programming and debugging
– Virtual serial port (CDC)
– Two debug GPIO channels (DGI GPIO)
• USB Powered
• Adjustable Target Voltage:
– MIC5353 LDO regulator controlled by the on-board debugger
– 1.8–5.1V output voltage (limited by USB input voltage)
– 500 mA maximum output current (limited by ambient temperature and output voltage)
1.2 Board Overview
The Microchip ATmega4809 Curiosity Nano Evaluation Kit is a hardware platform to evaluate the ATmega4809
microcontroller.
Figure 1-1. ATmega4809 Curiosity Nano Board Overview
Micro-USB
Connector Debugger
Power/Status
LED
32.768 kHz
Crystal Footprint
User LED
(LED0)
User Switch
(SW0)
ATmega4809
MCU
ATmega4809 Curiosity Nano
Introduction
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2. Getting Started
2.1 Quick Start
Steps to start exploring the ATmega4809 Curiosity Nano board:
1. Download Microchip MPLAB® X IDE and MPLAB® XC C Compiler, or download Atmel Studio 7.
2. Launch MPLAB® X IDE or Atmel Studio 7.
3. Optional: Use MPLAB® Code Configurator or Atmel START to generate drivers and examples.
4. Write your application code.
5. Connect a USB cable (Standard-A to Micro-B or Micro-AB) between the PC and the debug USB port on the
board.
Info:
• MPLAB® X IDE supports XC C compilers and the AVR® and Arm® Toolchains (GCC Compilers)
• Microchip’s XC8 C Compiler supports all 8-bit PIC® and AVR® microcontrollers
• Included in the Atmel Studio 7 download are the AVR® and Arm® Toolchains (GCC Compilers)
2.1.1 Driver Installation
When the board is connected to your computer for the first time, the operating system will perform a driver software
installation. The driver file supports both 32- and 64-bit versions of Microsoft® Windows® XP, Windows Vista®,
Windows 7, Windows 8, and Windows 10. The drivers for the board are included with both MPLAB® X IDE and Atmel
Studio 7.
2.1.2 Kit Window
Once the board is powered, the green status LED will be lit, and both MPLAB® X IDE and Atmel Studio 7 will auto-
detect which boards are connected. The Kit Window in MPLAB® X IDE and Atmel Studio 7 will present relevant
information like data sheets and board documentation. The ATmega4809 device on the ATmega4809 Curiosity Nano
board is programmed and debugged by the on-board debugger and, therefore, no external programmer or debugger
tool is required.
Tip: The Kit Window can be opened in MPLAB® X IDE through the menu bar Window > Kit Window.
2.2 Design Documentation and Relevant Links
The following list contains links to the most relevant documents and software for the ATmega4809 Curiosity Nano
board:
•MPLAB® X IDE - MPLAB X IDE is a software program that runs on a PC (Windows®, Mac OS®, Linux®) to
develop applications for Microchip microcontrollers and digital signal controllers. It is called an Integrated
Development Environment (IDE) because it provides a single integrated “environment” to develop code for
embedded microcontrollers.
•Atmel Studio - Free IDE for the development of C/C++ and assembler code for microcontrollers.
•IAR Embedded Workbench® for AVR® - This is a commercial C/C++ compiler that is available for AVR
microcontrollers. There is a 30-day evaluation version as well as a 4 KB code-size-limited kick-start version
available from their website.
ATmega4809 Curiosity Nano
Getting Started
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•MPLAB® XC Compilers - MPLAB® XC8 C Compiler is available as a free, unrestricted-use download.
Microchips MPLAB® XC8 C Compiler is a comprehensive solution for your project’s software development on
Windows®, macOS® or Linux®. MPLAB® XC8 supports all 8-bit PIC® and AVR® microcontrollers (MCUs).
•MPLAB® Code Configurator - MPLAB Code Configurator (MCC) is a free software plug-in that provides a
graphical interface to configure peripherals and functions specific to your application.
•Atmel START - Atmel START is an online tool that hosts code examples, helps the user to select and configure
software components, and tailor your embedded application in a usable and optimized manner.
•Microchip Sample Store - Microchip sample store where you can order samples of devices.
•MPLAB Data Visualizer - MPLAB Data Visualizer is a program used for processing and visualizing data. The
Data Visualizer can receive data from various sources such as serial ports and on-board debugger’s Data
Gateway Interface, as found on Curiosity Nano and Xplained Pro boards.
•Studio Data Visualizer - Studio Data Visualizer is a program used for processing and visualizing data. The
Data Visualizer can receive data from various sources such as serial ports, on-board debugger’s Data Gateway
Interface as found on Curiosity Nano and Xplained Pro boards, and power data from the Power Debugger.
•Microchip PIC® and AVR® Examples - Microchip PIC and AVR Device Examples is a collection of examples
and labs that use Microchip development boards to showcase the use of PIC and AVR device peripherals.
•Microchip PIC® and AVR® Solutions - Microchip PIC and AVR Device Solutions contains complete
applications for use with Microchip development boards, ready to be adapted and extended.
•ATmega4809 Curiosity Nano website - Kit information, latest user guide, and design documentation.
•ATmega4809 Curiosity Nano on microchipDIRECT - Purchase this kit on microchipDIRECT.
ATmega4809 Curiosity Nano
Getting Started
© 2020 Microchip Technology Inc. User Guide DS50002804B-page 6

3. Curiosity Nano
Curiosity Nano is an evaluation platform of small boards with access to most of the microcontrollers I/Os. The
platform consists of a series of low pin count microcontroller (MCU) boards with on-board debuggers, which are
integrated with MPLAB® X IDE and Atmel Studio 7. Each board is identified in the IDE. When plugged in, a Kit
Window is displayed with links to key documentation, including relevant user guides, application notes, data sheets,
and example code. Everything is easy to find. The on-board debugger features a virtual serial port (CDC) for serial
communication to a host PC and a Data Gateway Interface (DGI) with debug GPIO pin(s).
3.1 On-Board Debugger Overview
ATmega4809 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 ATmega4809 in both MPLAB® X IDE and Atmel Studio 7
• A mass storage device that allows drag-and-drop programming of the ATmega4809
• A virtual serial port (CDC) that is connected to a Universal Asynchronous Receiver/Transmitter (UART) on the
ATmega4809, 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 ATmega4809 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.
3.1.1 Debugger
The on-board debugger on the ATmega4809 Curiosity Nano board appears as a Human Interface Device (HID) on
the host computer’s USB subsystem. The debugger supports full-featured programming and debugging of the
ATmega4809 using both MPLAB® X IDE and Atmel Studio 7, as well as some third-party IDEs.
ATmega4809 Curiosity Nano
Curiosity Nano
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Remember: Keep the debugger’s firmware up-to-date. Firmware upgrades are automatically done when
using MPLAB® X IDE or Atmel Studio 7.
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: As shown in Figure 3-1, 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, a USB driver is required for CDC. This driver is included in installations
of both MPLAB® X IDE and Atmel Studio 7.
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#.
ATmega4809 Curiosity Nano
Curiosity Nano
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Info: For all operating systems: Be sure to use a terminal emulator that supports DTR signaling. See
3.1.2.4 Signaling.
3.1.2.3 Limitations
Not all UART features are implemented in the on-board debugger CDC. The constraints are outlined here:
•Baud rate: Must be in the range of 1200 bps to 500 kbps. Any baud rate outside this range will be set to the
closest limit, 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.
•Stop bits: One or two bits are supported.
3.1.2.4 Signaling
During USB enumeration, the host OS will start both communication and data pipes of the CDC interface. At this
point, it is possible to set and read back the baud rate and other UART parameters of the CDC, but data sending and
receiving will not be enabled.
When a terminal connects on the host, it must assert the DTR signal. As this is a virtual control signal implemented
on the USB interface, it is not physically present on the board. Asserting the DTR signal from the host will indicate to
the on-board debugger that a CDC session is active. The debugger will then enable its level shifters (if available) and
start the CDC data send and receive mechanisms.
Deasserting DTR in debugger firmware version 1.20 or earlier has the following behavior:
• Debugger UART receiver is disabled, so no further data will be transferred to the host computer
• Debugger UART transmitter will continue to send data that is queued for sending, but no new data is accepted
from the host computer
• Level shifters (if available) are not disabled, so the debugger CDC TX line remains driven
Deasserting DTR in debugger firmware version 1.21 or later has the following behavior:
• Debugger UART receiver is disabled, so no further data will be transferred to the host computer
• Debugger UART transmitter will continue to send data that is queued for sending, but no new data is accepted
from the host computer
• Once the ongoing transmission is complete, level shifters (if available) are disabled, so the debugger CDC TX
line will become high-impedance
Remember: Set up the terminal emulator to assert the DTR signal. Without the signal, the on-board
debugger will not send or receive any data through its UART.
Tip: The on-board debugger’s CDC TX pin will not be driven until the CDC interface is enabled by the
host computer. Also, there are no external pull-up resistors on the CDC lines connecting the debugger and
the target, which means that during power-up, these lines are floating. To avoid any glitches resulting in
unpredictable behavior like framing errors, the target device should enable the internal pull-up resistor on
the pin connected to the debugger’s CDC TX pin.
ATmega4809 Curiosity Nano
Curiosity Nano
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3.1.2.5 Advanced Use
CDC Override Mode
In normal operation, the on-board debugger is a true UART bridge between the host and the device. However, in
certain use cases, the on-board debugger can override the basic operating mode and use the CDC TX and RX pins
for other purposes.
Dropping a text file into the on-board debugger’s mass storage drive can be used to send characters out of the
debugger’s CDC TX pin. The filename and extension are trivial, but the text file must start with the characters:
CMD:SEND_UART=
Debugger firmware version 1.20 or earlier has the following limitations:
• The maximum message length is 50 characters – all remaining data in the frame are ignored
• The default baud rate used in this mode is 9600 bps, but if the CDC is already active or has been configured,
the previously used baud rate still applies
Debugger firmware version 1.21 and later has the following limitations/features:
• The maximum message length may vary depending on the MSC/SCSI layer timeouts on the host computer
and/or operating system. A single SCSI frame of 512 bytes (498 characters of payload) is ensured, and files of
up to 4 KB will work on most systems. The transfer will complete on the first NULL character encountered in the
file.
• The baud rate used is always 9600 bps for the default command:
CMD:SEND_UART=
The CDC Override Mode should not be used simultaneously with data transfer over the CDC/terminal. If a CDC
terminal session is active at the time a file is received via CDC Override Mode, it will be suspended for the
duration of the operation and resumed once complete.
• Additional commands are supported with explicit baud rates:
CMD:SEND_9600=
CMD:SEND_115200=
CMD:SEND_460800=
USB-Level Framing Considerations
Sending data from the host to the CDC can be done byte-wise or in blocks, which will be chunked into 64-byte USB
frames. Each such frame will be queued up for sending to the debugger’s CDC TX pin. Transferring a small amount
of data per frame can be inefficient, particularly at low baud rates, as the on-board debugger buffers frames and not
bytes. A maximum of four 64-byte frames can be active at any time. The on-board debugger will throttle the incoming
frames accordingly. Sending full 64-byte frames containing data is the most efficient method.
When receiving data on the debugger’s CDC RX pin, the on-board debugger will queue up the incoming bytes into
64-byte frames, which are sent to the USB queue for transmission to the host when they are full. Incomplete frames
are also pushed to the USB queue at approximately 100 ms intervals, triggered by USB start-of-frame tokens. Up to
eight 64-byte frames can be active at any time.
If the host (or the software running on it) fails to receive data fast enough, an overrun will occur. When this happens,
the last-filled buffer frame will be recycled instead of being sent to the USB queue, and a full data frame will be lost.
To prevent this occurrence, the user must ensure that the CDC data pipe is being read continuously, or the incoming
data rate must be reduced.
3.1.3 Mass Storage Device
The on-board debugger includes a simple Mass Storage Device implementation, which is accessible for read/write
operations via the host operating system to which it is connected.
It provides:
• Read access to basic text and HTML files for detailed kit information and support
ATmega4809 Curiosity Nano
Curiosity Nano
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