Microchip Technology AVR64EA48 User manual

© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 1
AVR64EA48
AVR64EA48 Curiosity Nano Hardware User Guide
Preface
The AVR64EA48 Curiosity Nano evaluation kit (EV66E56A) is a hardware platform to evaluate the AVR® EA Family
microcontrollers. This board has the AVR64EA48 microcontroller (MCU) mounted.
Supported by both MPLAB® X IDE and Microchip Studio, the board provides easy access to the features of the
AVR64EA48 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 AVR64EA48.
•MPLAB® X IDE and Microchip Studio - Software to discover, configure, develop, program, and debug
Microchip microcontrollers.
•Code examples on MPLAB Discover - Get started with code examples.
•AVR64EA48 website - Find documentation, data sheets, sample, and purchase microcontrollers.
•AVR64EA48 Curiosity Nano website - Kit information, latest user guide and design documentation.

AVR64EA48
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 2
Table of Contents
Preface........................................................................................................................................................... 1
1. Introduction............................................................................................................................................. 3
1.1. Features....................................................................................................................................... 3
1.2. Board Overview............................................................................................................................3
2. Getting Started........................................................................................................................................ 4
2.1. Curiosity Nano Quick Start MPLAB® Xpress............................................................................... 4
2.2. Quick Start....................................................................................................................................4
2.3. Design Documentation and Relevant Links................................................................................. 5
3. Curiosity Nano.........................................................................................................................................7
3.1. On-Board Debugger Overview..................................................................................................... 7
3.2. Curiosity Nano Standard Pinout................................................................................................. 14
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 Description............................................................................................................................25
4.1. Connectors.................................................................................................................................25
4.2. Peripherals................................................................................................................................. 26
5. Hardware Revision History and Known Issues..................................................................................... 30
5.1. Identifying Product ID and Revision........................................................................................... 30
5.2. Revision 3...................................................................................................................................30
6. Document Revision History...................................................................................................................31
7. Appendix............................................................................................................................................... 32
7.1. Schematic...................................................................................................................................33
7.2. Assembly Drawing......................................................................................................................35
7.3. Curiosity Nano Base for Click boards™...................................................................................... 36
7.4. Disconnecting the On-Board Debugger..................................................................................... 37
7.5. Getting Started with IAR™...........................................................................................................38
Microchip Information................................................................................................................................... 41
The Microchip Website..........................................................................................................................41
Product Change Notification Service.................................................................................................... 41
Customer Support................................................................................................................................. 41
Microchip Devices Code Protection Feature.........................................................................................41
Legal Notice.......................................................................................................................................... 41
Trademarks........................................................................................................................................... 42
Quality Management System................................................................................................................ 43
Worldwide Sales and Service................................................................................................................44

AVR64EA48
Introduction
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 3
1. Introduction
1.1 Features
• AVR64EA48 Microcontroller
• One Yellow User LED
• One Mechanical User Switch
• One 32.768 kHz Crystal
• One 20 MHz Crystal
• On-Board Debugger:
– Board identification in Microchip MPLAB® X IDE and Microchip Studio
– 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 AVR64EA48 Curiosity Nano evaluation kit is a hardware platform to evaluate the AVR64EA48
microcontroller.
Figure 1-1. AVR64EA48 Curiosity Nano Board Overview

AVR64EA48
Getting Started
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 4
2. Getting Started
2.1 Curiosity Nano Quick Start MPLAB® Xpress
MPLAB Xpress Cloud-Based IDE is part of the MPLAB Cloud tools ecosystem, leveraging the intuitive MPLAB
Discover for finding projects and code examples and the MPLAB Code Configurator graphical configuration tool to
provide an all-in cloud experience.
Steps to start exploring the Curiosity Nano platform with MPLAB Xpress:
1. Go to www.mplab-xpresside.microchip.com/ to open MPLAB Xpress.
2. Create a new standalone project for AVR64EA48.
3. Use the MPLAB Xpress Code Configurator, or write your code.
4. Compile and download the application HEX file.
5. Connect a USB cable (Standard-A to Micro-B or Micro-AB) between the PC and the debug USB port on the
board.
6. Copy the application HEX file into the CURIOSITY mass storage drive to program the application into the
AVR64EA48.
To use the advanced debug features of the Curiosity Nano kit, package the MPLAB Xpress project for MPLAB
X IDE, and follow the quick start guide in the next section.
2.2 Quick Start
Steps to start exploring the AVR64EA48 Curiosity Nano board:
1. Download Microchip MPLAB® X IDE and MPLAB® XC C Compiler, or download Microchip Studio.
2. Launch MPLAB® X IDE or Microchip Studio.
3. Optional: Use MPLAB® Code Configurator to generate drivers and examples.
4. Write\Develop the 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.
6. Program your application onto the device.
The AVR64EA48 device on the AVR64EA48 Curiosity Nano board is programmed and debugged by the
on-board debugger. Therefore, no external programmer or debugger tool is required.
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 Microchip Studio download are the AVR® and Arm® Toolchains (GCC
Compilers)
2.2.1 Driver Installation
When the board connects to the 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®. The drivers for the board
are included with both MPLAB® X IDE and Microchip Studio.

AVR64EA48
Getting Started
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 5
2.2.2 Kit Window
When the board is connected to a computer and powered on, the green status LED will be lit, and both MPLAB®
X IDE and Microchip Studio will auto-detect which boards are connected. The Kit Window in MPLAB® X IDE and
Microchip Studio will present relevant information like data sheets and board documentation.
Tip: If closed, reopen the Kit Window in MPLAB® X IDE through the menu bar Window > Kit Window.
2.2.3 MPLAB® X IDE Device Family Packs
Microchip MPLAB® X IDE requires specific information to support devices and tools. This information is contained
in versioned packs. For the AVR64EA48 Curiosity Nano board, MPLAB® X version 6.0 with device family pack “AVR-
Ex_DFP” version 2.1.48 and tool pack “nEDBG_TP” version 1.10.488 or newer is required. For more information on
packs and how to upgrade them, refer to the MPLAB® X IDE User’s guide - Work with Device Packs.
Tip: The latest device family packs are available through Tools > Packs in MPLAB® X IDE or online at
Microchip MPLAB® X Packs Repository.
2.2.4 Microchip Studio Device Family Pack
Microchip Studio requires specific information to support devices. This information is contained in versioned packs.
For the AVR64EA48 Curiosity Nano board, the device family pack “AVR-Ex_DFP” version 2.2.56 or newer is
required. For more information on packs and how to upgrade them, refer to the Microchip Studio User Guide -
Device Pack Manager.
Tip: The latest device family packs are available through Tools > Device Pack Manager in Microchip
Studio or online at Microchip Studio Packs Repository.
2.3 Design Documentation and Relevant Links
The following list contains links to the most relevant documents and software for the AVR64EA48 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 named an Integrated
Development Environment (IDE) because it provides a single integrated “environment” to develop code for
embedded microcontrollers.
•Microchip 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 available for AVR
microcontrollers. There is a 30-day evaluation version and a 4 KB code-size-limited kick-start version available
from their website.
•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 the project’s software development on
Windows®, macOS® or Linux®. MPLAB® XC8 supports all 8-bit PIC® and AVR® microcontrollers (MCUs).
•MPLAB® Xpress Cloud-Based IDE - MPLAB Xpress Cloud-Based IDE is an online development environment
containing the most popular features of our award-winning MPLAB X IDE. This simplified and distilled
application is a faithful reproduction of our desktop-based program, allowing users an easy transition between
the two environments.

AVR64EA48
Getting Started
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 6
•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.
•Microchip Sample Store - Microchip sample store where one 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 the on-board debugger’s Data
Gateway Interface, as found on Curiosity Nano and Xplained Pro boards.
•Atmel 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, the on-board debugger’s Data Gateway
Interface found on Curiosity Nano and Xplained Pro boards, and power data from the Power Debugger.
•MPLAB Discover - MPLAB Discover is a tool to help you find Microchip example projects and collateral for
Microchip devices.
•AVR64EA48 Curiosity Nano website - Kit information, latest user guide and design documentation.
•AVR64EA48 Curiosity Nano on Microchip Direct - Purchase this kit on Microchip Direct.

AVR64EA48
Curiosity Nano
© 2023 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003494A-page 7
3. Curiosity Nano
Curiosity Nano is an evaluation platform of small boards with low pin count microcontroller (MCU) boards with
on-board debuggers and access to most microcontrollers I/Os. The Curiosity Nano platform offers easy integration
with MPLAB® X IDE and Microchip Studio. All boards are identified in the IDE. When connected, a Kit Window
appears 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
AVR64EA48 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 AVR64EA48 in both MPLAB® X IDE and Microchip Studio
• A mass storage device that allows drag-and-drop programming of the AVR64EA48
• A virtual serial port (CDC) that is connected to a Universal Asynchronous Receiver/Transmitter (UART) on the
AVR64EA48 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 AVR64EA48 Curiosity Nano board.
The table below shows how the different operation modes control the LED.
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 about 5 Hz.
3.1.1 Debugger
The on-board debugger on the AVR64EA48 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
AVR64EA48 by using both MPLAB X IDE and Microchip Studio and some third-party IDEs.

AVR64EA48
Curiosity Nano
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User Guide DS50003494A-page 8
Remember: Keep the debugger’s firmware up-to-date. Firmware upgrades automatically when using
MPLAB X IDE or Microchip Studio.
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 with a standard Communications Device Class (CDC)
interface, which appears on the host as a virtual serial port. Use the CDC to stream arbitrary data between the host
computer and the target in both directions: All characters sent through the virtual serial port on the host computer will
be transmitted as UART on the debugger’s CDC TX pin. The 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 DSC
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, as shown in the figure above. 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 driver. Both MPLAB X IDE and Microchip
Studio installationsinclude this driver.
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 permission to access the CDC.
On Mac® machines, the CDC will enumerate and appear as /dev/tty.usbmodem#. Depending on the terminal
program used, it will appear in the available list of modems as usbmodem#.

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Curiosity Nano
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Info: For all operating systems, 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 the 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.
The terminal must assert the DTR signal when it connects to the host. 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 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, and no further data will be transferred to the host computer
• Debugger UART transmitter will continue to send queued data ready for transfer, but no new data is accepted
from the host computer
• Level shifters (if available) are not disabled, and 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, and no further data will be transferred to the host computer
• Debugger UART transmitter will continue to send queued data ready for transfer, but no new data is accepted
from the host computer
• Once the ongoing transmission is complete, level shifters (if available) are disabled, and 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 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 the lines are floating during power-up. The target device may enable the
internal pull-up resistor on the pin connected to the debugger’s CDC TX pin to avoid glitches resulting in
unpredictable behavior like framing errors.

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Curiosity Nano
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and its subsidiaries
User Guide DS50003494A-page 10
3.1.2.5 Advanced Use
CDC Override Mode
In ordinary 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 will 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 configured, the
previously used baud rate still applies
Debugger firmware version 1.21 and later has the following limitations/features:
• The maximum message length will 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 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=
• Do not use the CDC Override mode simultaneously with data transfer over the CDC/terminal. If a CDC terminal
session is active when receiving a file via the 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, chunked into 64-byte USB frames. Each
frame will be queued for transfer to the debugger’s CDC TX pin. Sending a small amount of data per frame can
be inefficient, particularly at low baud rates, as the on-board debugger buffers frames but 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.
An overrun will occur if the host (or the software running on it) fails to receive data fast enough. When this happens,
the last-filled buffer frame recycles instead of being sent to the USB queue, and a complete data frame will be lost. To
prevent this occurrence, the user will ensure that the CDC data pipe is continuously read, or the incoming data rate
will be reduced.
Sending Break Characters
The host can send a UART break character to the device using the CDC, which can be useable for resetting a
receiver state-machine or signalling an exception condition from the host to the application running on the device.
A break character is defined as a sequence of at least 11 zero bits transmitted from the host to the device.
Not all UART receivers have support for detecting a break, but a correctly-formed break character usually triggers a
framing error on the receiver.