AVR 8-bit Microcontrollers ATmega328PB Xplained Mini USER GUIDE Introduction (R) This user guide describes how to get started with the Atmel ATmega328PB Xplained Mini board. The ATmega328PB Xplained Mini evaluation kit is a hardware platform to evaluate the Atmel ATmega328PB microcontroller. The evaluation kit comes with a fully integrated debugger that provides seamless integration with Atmel Studio 6.2 (and later version). The kit provides access to the features of the ATmega328PB enabling easy integration of the device in a custom design. Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 Table of Contents Introduction......................................................................................................................1 1. Getting Started...........................................................................................................3 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. Features....................................................................................................................................... 3 Design Documentation and Related Links................................................................................... 3 Xplained Mini Quick Start............................................................................................................. 3 1.3.1. Connect to Atmel Studio................................................................................................ 3 1.3.2. Connect to the COM Port.............................................................................................. 4 Programming and Debugging...................................................................................................... 4 1.4.1. Programming the Target Using mEDBG........................................................................4 1.4.2. Debugging the Target Using mEDBG............................................................................ 5 1.4.3. Programming the Target Using an External Programmer..............................................6 1.4.4. Programming the ATmega32U4 Using an External Programmer.................................. 6 1.4.5. Programming the ATmega32U4 Using a Bootloader.....................................................7 Board Assembly........................................................................................................................... 8 1.5.1. Custom Assembly..........................................................................................................8 1.5.2. Standalone Node........................................................................................................... 8 1.5.3. Connecting an Arduino Shield....................................................................................... 8 mEDBG Command Line Interface................................................................................................8 1.6.1. mEDBG Low Power Modes........................................................................................... 8 1.6.2. mEDBG Fuse Filter........................................................................................................8 1.6.3. How to Issue Commands...............................................................................................8 2. Hardware User Guide.............................................................................................. 11 2.1. 2.2. 2.3. 2.4. 2.5. 2.6. 2.7. 2.8. Board Overview.......................................................................................................................... 11 Target Headers and Connectors.................................................................................................11 2.2.1. Target Digital I/O.......................................................................................................... 11 2.2.2. Board Power Header................................................................................................... 12 2.2.3. Target Analogue I/O.....................................................................................................12 2.2.4. Target Programming.................................................................................................... 13 2.2.5. Target Additional I/O.................................................................................................... 13 Target GUI.................................................................................................................................. 13 2.3.1. Push Button................................................................................................................. 14 2.3.2. User LED..................................................................................................................... 14 2.3.3. QTouch buttons............................................................................................................15 On-board Power Supply............................................................................................................. 16 mEDBG...................................................................................................................................... 16 2.5.1. mEDBG Status LED.................................................................................................... 16 2.5.2. mEDBG External Clock............................................................................................... 17 2.5.3. mEDBG COM Port Connection................................................................................... 17 2.5.4. mEDBG JTAG Interface...............................................................................................17 2.5.5. mEDBG USB Interface................................................................................................ 18 Extension Header Area.............................................................................................................. 18 Factory Programmed..................................................................................................................19 Document Revision History........................................................................................................ 20 Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 2 1. Getting Started 1.1. Features The ATmega328PB Xplained Mini evaluation board provides a development platform for the Atmel ATmega328PB. Key Features * * * * * * * * * * * * * * 1.2. On-board debugger with full source-level debugging support in Atmel Studio Auto-ID for board identification in Atmel Studio Access to all signals on target MCU One green mEDBG status LED One yellow user LED One mechanical user push button QTouch(R) user area Virtual COM port (CDC) External target CLK 16MHz at 5V, 8MHz at 3.3V USB powered 3.3V regulator Arduino shield compatible foot prints Target SPI bus header foot print Xplained Pro extension headers can easily be strapped in Design Documentation and Related Links The most relevant documents and software for the evaluation board are available here: Design Documentation - A .zip file containing CAD source, schematics, BOM, assembly drawings, 3D plots, layer plots, etc. Atmel Studio - Free Atmel IDE for development of C/C++ and assembler code for Atmel microcontrollers. Xplained - Atmel Xplained prototyping and evaluation platform. Atmel Spaces - Open Source projects for Xplained Mini. 1.3. Xplained Mini Quick Start How to connect the ATmega328PB Xplained Mini board embedded debugger to Atmel Studio and how to connect the ATmega328PB UART to a COM port. 1.3.1. Connect to Atmel Studio How to connect the ATmega328PB Xplained Mini board embedded debugger to Atmel Studio to get started with SW development. 1. 2. 3. Download and install Atmel Studio version 6.2 or later versions. Launch Atmel Studio. Connect the board to the USB port and it will be visible in Atmel Studio. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 3 1.3.2. Connect to the COM Port How to connect the ATmega328PB UART to a COM port. All Xplained Mini boards have an embedded debugger (mEBDG) with a number of features, among them a CDC/COM port, which enables the user to connect the ATmega328PB UART to the PC. 1. 2. 3. 1.4. Connect the Xplained Mini USB to the PC. A COM port named "mEDBG Virtual COM Port" will be available. Start a terminal emulator or other applications using the COM port, typical COM port settings are 9600 baud N81. Programming and Debugging Programming and debugging the ATmega328PB Xplained Mini. The target microcontroller is the ATmega328PB. The mEDBG FW is running on the ATmega32U4. 1.4.1. Programming the Target Using mEDBG Using the Embedded Debugger on the ATmega328PB Xplained Mini board to program the ATmega328PB. 1. 2. 3. 4. Connect the Xplained Mini USB to the PC. Go to Atmel Studio: click the Tools tab, select Device Programming, and select the connected mEDBG as Tool with Device as ATmega328PB and Interface to SPI, click Apply. Select "Memories" and locate the source .hex or .elf file and click Program. NOTE: If a previous debug session was not closed by selecting "Disable debugWIRE and Close" in the Debug menu, the DWEN fuse will be enabled and the target will still be in debug mode, i.e. it will not be possible to program the target using the SPI. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 4 5. 6. 1.4.2. If the source file contains fuse settings, select "Production file" and upload the .elf file to program the fuses. Select "Fuses" to program the fuses manually. Set the fuse(s) and click "Program". Recommended fuse settings: Debugging the Target Using mEDBG Using the Embedded Debugger on the ATmega328PB Xplained Mini board to debug the ATmega328PB via debugWIRE. 1. 2. 3. 4. 5. 6. 7. 8. Start Atmel Studio. Connect the Xplained Mini USB to the PC. Open your project. Click the "Project" tab and select the project "properties", click the "Tools" tab and select mEDBG as debugger and debugWIRE as interface. Click the "Debug" tab and select "Start Debugging and Break". Atmel Studio will display an error message if the DWEN fuse in the ATmega328PB is not enabled, click YES to make Studio set the fuse using the SPI interface. A debug session is started with a break in main, debugging can start. When exiting debug mode select "Disable debugWIRE and Close" in the Debug tab, this will disable the DWEN fuse. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 5 Important: If not exiting debug mode by selecting "Disable debugWIRE and Close" in the Debug menu, the DWEN fuse will be enabled and the target will still be in debug mode, i.e. it will not be possible to program the target using the SPI. Important: If any other CPU CLK than the external CLK supplied by the mEDBG is used the debugWIRE is not guaranteed to work. Important: Applying a signal to J202/RESET (the RESET_SENSE signal) while debugging may result in unexpected behavior. This signal is NOT available during a debugging session because the RESET line is actively used by the debugWIRE interface 1.4.3. Programming the Target Using an External Programmer (R) How to program the target ATmega328PB using the AVR JTAGICE mkII, JTAGICE3, Atmel-ICE, or other Atmel Programmers. 1. 2. 3. 4. 1.4.4. Connect the External Programmer USB to the PC. Connect the External Programmer to the ATmega328PB Xplained Mini board SPI connector. Go to Atmel Studio: Click the Tools tab, select Device Programming, and select the External Programmer connected as Tool with Device as ATmega328PB and Interface to SPI, click Apply. Select "Memories" and locate the source .hex or .elf file and click Program. Programming the ATmega32U4 Using an External Programmer How to program the ATmega32U4 using the AVR JTAGICE mkII, JTAGICE3, Atmel-ICE, or other Atmel Programmers. 1. 2. 3. 4. Connect the External Programmer USB to the PC. Connect the External Programmer to the ATmega328PB Xplained Mini board JTAG connector. Go to Atmel Studio: click the Tools tab, select Device Programming, and select the connected mEDBG as Tool with Device as ATmega32U4 and Interface to JTAG, click Apply. Select "Memories" and locate the source .hex or .elf file and click Program. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 6 5. 1.4.5. Select "Fuses" to program the fuses manually. Set the fuse(s) and click "Program". Recommended fuse settings: Programming the ATmega32U4 Using a Bootloader This section describes how to use the bootloader to program the ATmega32U4. 1. 2. 3. 4. 5. 6. 7. 8. Install the Bootloader interface on the PC, download the installer from FLIP. Start the Bootloader PC GUI "FLIP". Short strap J102. Connect the ATmega328PB Xplained Mini board USB connector to the PC. Select Device = ATmega32U4 (Device - Select). Select USB communication (Ctrl+U). Select memory area to program (use the toggle memory button bellow the Atmel logo). Select Load Hex file (Ctrl+L). Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 7 9. Select Programming Options. 10. Click "Run", observe status in status field. 1.5. Board Assembly The Xplained Mini board can easily be assembled into a product prototype for software development and hardware verification. 1.5.1. Custom Assembly All signals of the ATmega328PB are available in the Xplained Mini board connector grid, enabling easy connection of external sensors and output devices in order to prototype the customer specific application. 1.5.2. Standalone Node The ATmega328PB Xplained Mini board can be used as a standalone node with an external power source, e.g. the 4xAAA or 2xAAA battery pack available from Atmel. 1.5.3. Connecting an Arduino Shield (R) Arduino shields can be mounted in the marked positions (J200, J201, J202, and J203). 1.6. mEDBG Command Line Interface The mEDBG has a command line interface enabling configuration of the mEDBG. 1.6.1. mEDBG Low Power Modes There are two modes enabling the Xplained Mini to save power when connected to an external power source other than an USB connection. Sleep Mode where the mEDBG is disabled. When enabled the ATmega32U4 will enter sleep mode if not enumerated within about 5sec. In this mode the external clock is not available to the target MCU. 1MHz Mode where the mEDBG/ATmega32U4 is set to run at 1MHz, saving power while maintaining the USB connection for the COM port. The external clock will be 1MHz. Table 1-1 Available Commands Mode Command External CLK COM port mEDBG program mEDBG debug Sleep 0xFB (bit2=0) disabled disabled disabled disabled 1MHz 0xFD (bit1=0) 1MHz enabled useless useless 16MHz (@5V) 8MHz (@3.3V) enabled enabled enabled Factory settings 0xFF 1.6.2. mEDBG Fuse Filter The mEDBG does not initially allow users to program the CLK related fuses in the target. This is done to avoid problems with the debugger when the target and mEDBG is not in CLK sync. This filter can be disabled by issuing the command 0xFE (bit0 = 0) enabling configuration of all ATmega328PB fuses. 1.6.3. How to Issue Commands The command line interface is supported by mEDBG version 1.6 or later. (R) The mEDBG command line interface can be accessed with the Python script found on Atmel Spaces Releases (mEDBG_script.zip). Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 8 If you have Studio 7.0 (and later versions), the mEDBG included supports the command line interface, if not, the mEDBG can be downloaded from Atmel Spaces Releases (medbg_fw.zip). Basic Python is required to run the script, Python can be downloaded from Python. How to Issue Commands 1. 2. 3. 4. Install Python. Download the file "mEDBG_script.zip" from Atmel Spaces Releases. Unzip the file "mEDBG_script.zip". Edit "stuff.py" to issue the selected command "c.set_suffer(0xXX)". 5. Open a command window in the directory where "stuff.py" is located. (Browse to the, folder rightclick on folder with shift pressed and select "Open command window here".) 6. Connect the Xplained Mini. 7. Run "stuff.py" (c:\Python27\python stuff.py). 8. The script will print the selected tool and display SUFFER setting. 9. Recycle power (disconnect/connect the board) for the change to take effect. 10. Edit "stuff.py" to issue the command c.set_suffer(0xFF) to reset to factory setting. How to Upgrade the Xplained Mini mEDBG 1. 2. 3. 4. 5. Start Atmel Studio. Connect the Xplained Mini to the computer. In Atmel Studio, select Tools - Device programming (Ctrl - Shift - P). In the Device Programming window, select Tool to mEDBG and click Apply. If there is a new mEDBG version available, the Atmel Studio will ask if you want to upgrade. To verify mEDBG version, click "Tool Information" when mEDBG is selected as Tool. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 9 Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 10 2. 2.1. Hardware User Guide Board Overview The ATmega328PB Xplained Mini headers overview. 2.2. Target Headers and Connectors The ATmega328PB related headers. 2.2.1. Target Digital I/O The J200 and J201 headers provide access to the ATmega328PB digital I/O pins. Table 2-1 J200 Digital I/O High Byte Header J200 pin ATmega328PB pin Function 1 PB0 2 PB1 3 PB2 SS, SPI Bus Master Slave select 4 PB3 MOSI, SPI Bus Master Output/Slave Input 5 PB4 MISO, SPI Bus Master Input/Slave Output 6 PB5 SCK, SPI Bus Master clock Input 7 GND 8 AREF Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 11 J200 pin ATmega328PB pin Function 9 PC4 SDA, 2-wire Serial Bus Data Input/Output Line. Shared with ADC4 10 PC5 SCL, 2-wire Serial Bus Clock Line. Shared with ADC5 Table 2-2 J201 Digital I/O High Low Header 2.2.2. J201 pin ATmega328PB pin Function 1 PD0 TXD (ATmega328PB USART Output Pin) 2 PD1 RXD (ATmega328PB USART Input Pin) 3 PD2 4 PD3 5 PD4 6 PD5 7 PD6 8 PD7 Board Power Header The J202 header enables connection to the ATmega328PB Xplained Mini power system. Table 2-3 J202 Power Header J202 pin Signal Description 1 NC 2 VCC_TARGET The power source selected for the target. (Select by J301) 3 RESET_SENSE This is a RESET signal monitored by the mEDBG, if pulled low the target RESET line will be pulled low by the mEDBG. The ATmega32U4 internal pull-up is enabled. This signal is not available during debugging. 4 VCC_P3V3 The 3.3V regulator output 5 VCC_P5V0 The selected power source. (VIN or VBUS selected by J300) 6 GND 7 GND 8 VCC_VIN The external power source connection. . 2.2.3. Target Analogue I/O The ATmega328PB ADC input pins are available in the J203 header. AREF is available in J200 pin 8. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 12 Table 2-4 J203 Analogue Header 2.2.4. J203 pin ATmega328PB pin Function 1 PC0 ADC Input Channel 0 2 PC1 ADC Input Channel 1 3 PC2 ADC Input Channel 2 4 PC3 ADC Input Channel 3 5 PC4 ADC Input Channel 4 6 PC5 ADC Input Channel 5 Target Programming The J204 header enable direct connection to the SPI bus with an external programmer for programming of the ATmega328PB. Table 2-5 SPI Header J204 pin ATmega328PB pin 1 PB4 2 MISO VCC target 3 PB5 SCK 4 PB3 MOSI 5 PC6 RESET 6 2.2.5. Function GND Target Additional I/O Signals not available in any of the headers or connectors, are available in column 5 of the grid. Table 2-6 Additional I/O 2.3. ATmega328PB pin Grid position PE0 J5 PE1 I5 PE2 H5 PE3 G5 Target GUI The ATmega328PB Xplained Mini has One LED, one push button, and a QTouch area. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 13 2.3.1. Push Button A general purpose push button, SW200, is connected to PB7. 2.3.2. User LED There is one yellow LED, D200, available for use by the application SW. The LED is connected to ATmega328PB pin 17 - PB5, the SCK signal from the mEDBG is in 3- state when not used. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 14 2.3.3. QTouch buttons Up to four QTouch buttons are available on the ATmega328PB Xplained Mini board. The QTouch area can be configured as buttons or as a limited slider. For a typical button or slider reference design use the QT1 Xplained Pro extension. Tip: There is a range of QTouch reference designs demonstrated with the QT Xplained Pro extensions located at Xplained - Atmel Xplained prototyping and evaluation platform. Table 2-7 QTouch Buttons Wiring Button ATmega328PB PTC A PE2 via 100k Y6 V PE3 via 100k Y7 R PC3 via 100k Y3 S Connected via 0 to A enabling slider configuration In the default HW configuration the QTouch area can be configured in SW as three buttons or as a limited slider. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 15 To get four buttons the S touch area can be connected to e.g. PC2 by removing the 0 resistor R214 and adding a wire or a 100k resistor from PC2 (D1) to the test point in B5.5. 2.4. On-board Power Supply The ATmega328PB Xplained Mini board has an on-board 3.3V regulator (150mA) which can be used to power the ATmega328PB. The J300 and J301 headers configure the ATmega328PB power supply and the board power source. The default configuration is set by R300 and R301 0 resistors which can be easily removed to change the default configuration. Table 2-8 Board Power Options Mode J301 connection, target J300 connection, board Function 5V (Default) pin2 connected to pin1 pin2 connected to pin1 Board and target powered by VBUS 3.3V USB pin2 connected to pin3, remove R301 pin2 connected to pin1 Target powered by 3.3V and USB interface powered by VBUS VIN pin2 connected to pin1 pin2 connected to pin3, Board and target powered by VIN, remove R300 J202.8. 1.8V < VIN < 5.5V 3.3V VIN pin2 connected to pin3, remove R301 pin2 connected to pin3, Target powered by 3.3V. VIN as remove R300 regulator input. 4V < VIN < 16V Tip: Use the BOD LEVEL fuse to avoid the following challenges: For the CPU to successfully decode and execute instructions, the supplied voltage must always stay above the minimum voltage level set by the chosen operating frequency. When supplied voltage drops below this level, the CPU may start to execute some instructions incorrectly. The result is unexpected activity on the internal data and control lines. This activity may cause CPU Registers, I/O Registers and Data Memories to get corrupted. To avoid these problems, the CPU should be prevented from executing code during periods of insufficient supply voltage. 2.5. mEDBG The ATmega328PB Xplained Mini board has an embedded debugger/programmer enabling debugging and programming of the ATmega328PB without any additional external equipment. 2.5.1. mEDBG Status LED The mEDBG has a green status LED connected to ATmega32U4 PC6 to signal the embedded debugger state. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 16 Table 2-9 mEDBG Green Status LED Function 2.5.2. mEDBG state LED Function Enumeration ON During the initial USB connection process the LED is on until enumerated or if not enumerated it is turned off within about 5 seconds Programming ON The LED is active during programming Debugging ON The LED is active when the debugger is running mEDBG External Clock The mEDBG (ATmega32U4) clock out signal (PC7) is connected to the ATmega328PB external clock input signal and can be used as the system clock source. The External Clock frequency is 16MHz when the target is running at 5V and 8MHz when running at 3.3V. Tip: The External Clock can be set to 1MHz to save power using the mEDBG command line interface. Tip: There is a test point marked EXT.CLK enabling easy measuring and/or connection to the CLK signal. 2.5.3. mEDBG COM Port Connection The mEDBG provide a CDC COM port connection when connected to a USB host device. The mEDBG (ATmega32U4) USART is used for communication with the CDC COM port. The USART TX/RX signals are available on the J104 header and are also connected to the ATmega328PB via 0 resistors enabling easy disconnect from the ATmega328PB if needed. Table 2-10 J104 USART Header J104 pin 2.5.4. ATmega32U4 ATmega328PB Function 1 - USART TxD PD3 PD1 TxD out from ATmega32U4 2 - USART RxD PD2 PD0 RxD in to ATmega32U4 mEDBG JTAG Interface The mEDBG (ATmega32U4) JTAG interface is available for programming and debugging of the ATmega32U4. Table 2-11 J100 JTAG Header J100 pin Signal name 1 TCK 2 GND 3 TDO 4 VCC_BOARD Description ATmega32U4 VCC Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 17 J100 pin Signal name 2.5.5. 5 TMS 6 RESET 7 NC 8 NC 9 TDI 10 GND Description Connected to ATmega32U4 only mEDBG USB Interface J101 is a Micro-B USB connector connected to the embedded debugger (ATmega32U4). Table 2-12 J101 USB Header J101 pin Signal name 1 VBUS 2 D- 3 D+ 4 NC 5 GND The VBUS has a resettable PTC fuse (F100), with a hold current of 0.5A and a trip current of 1.0A to protect the USB host device. 2.6. Extension Header Area The marked area on the grid I7 to R8 can be used for strapping in an Xplained Pro extension header or a 10-pin Xplained/RZ600 header. The SPI bus signals are made available close to the header at row J and K, enabling easy connection to header pin 15 to 18. Using Pin 11 to 20 enables connection of the 10-pin connector used on the RZ600 wireless modules and the 10-pin Xplained sensor modules. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 18 The general bus connections for an Xplained PRO Extension board is indicated in the table below, detailed wiring can be found in the selected extension board documentation. Table 2-13 Extension Header Typical Signals 2.7. Pin Signal name Signal description 1 ID Communication line to the ID chip on the Xplained extension board 2 GND Ground 3 ADC(+) Analog to digital converter, alternatively positive part of differential ADC 4 ADC(-) Analog to digital converter, alternatively negative part of differential ADC 5 GPIO1 General purpose I/O 6 GPIO2 General purpose I/O 7 PWM(+) Pulse width modulation, alternatively positive part of differential PWM 8 PWM(-) Pulse width modulation, alternatively negative part of differential PWM 9 IRQ/GPIO Interrupt request line and/or general purpose I/O 10 SPI_SS_B/ GPIO Slave B select for SPI and/or general purpose I/O 11 I2C_SDA Data line for I2C interface 12 I2C_SCL Clock line for I2C interface 13 UART_RX Receiver line of ATmega328PB USART 14 UART_TX Transmitter line of ATmega328PB USART 15 SPI_SS_A Slave A select for SPI 16 SPI_MOSI Master out slave in line of serial peripheral interface 17 SPI_MISO Master in slave out line of serial peripheral interface 18 SPI_SCK Clock for serial peripheral interface 19 GND Ground 20 VCC Power for extension board Factory Programmed The ATmega328PB is preprogrammed with a demo program, ReMorse. Source code is available in Atmel Spaces. When the CDC COM port is connected to a terminal window (9600 N81), the text you write will be transmitted via the LED in Morse code. Any Morse code transmitted by using the switch will be displayed as text in the terminal window. The ATmega32U4 is preprogrammed with the mEDBG. Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 19 2.8. Document Revision History Document revision Date Comment 42469B 08/2015 Slightly updated version 42469A 07/2015 Initial document release Atmel ATmega328PB Xplained Mini [USER GUIDE] Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 20 Atmel Corporation (c) 1600 Technology Drive, San Jose, CA 95110 USA T: (+1)(408) 441.0311 F: (+1)(408) 436.4200 | www.atmel.com 2015 Atmel Corporation. / Rev.: Atmel-42469B-ATmega328PB-Xplained-Mini_User Guide-08/2015 (R) (R) (R) (R) Atmel , Atmel logo and combinations thereof, Enabling Unlimited Possibilities , AVR , QTouch , and others are registered trademarks or trademarks of Atmel Corporation in U.S. and other countries. Other terms and product names may be trademarks of others. DISCLAIMER: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. 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