Microchip Technology ATtiny1607 Curiosity Nano Installation manual

ATtiny1607 Curiosity Nano
ATtiny1607 Curiosity Nano Hardware User Guide
Preface
The ATtiny1607 Curiosity Nano evaluation kit is a hardware platform to evaluate the ATtiny1607
microcontroller.
Supported by Atmel Studio/Microchip MPLAB® X Integrated Development Environment (IDE), the kit
provides easy access to the features of the ATtiny1607 to explore how to integrate the device into a
custom design.
The Curiosity Nano series of evaluation kits include an on-board debugger. No external tools are
necessary to program and debug the ATtiny1607.
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 1

Table of Contents
Preface............................................................................................................................ 1
1. Introduction................................................................................................................4
1.1. Features....................................................................................................................................... 4
1.2. Kit Overview................................................................................................................................. 4
2. Getting Started.......................................................................................................... 5
2.1. Curiosity Nano Quick Start........................................................................................................... 5
2.2. Design Documentation and Relevant Links................................................................................. 5
3. Curiosity Nano........................................................................................................... 6
3.1. On-board Debugger..................................................................................................................... 6
3.1.1. Virtual COM Port............................................................................................................6
3.1.1.1. Overview..................................................................................................... 6
3.1.1.2. Limitations................................................................................................... 7
3.1.1.3. Signaling......................................................................................................7
3.1.1.4. Advanced Use............................................................................................. 7
3.1.2. Mass Storage Disk.........................................................................................................8
3.1.2.1. Mass Storage Device.................................................................................. 8
3.1.2.2. Fuse Bytes.................................................................................................. 9
3.2. Curiosity Nano Standard Pinout................................................................................................... 9
3.3. Power Supply............................................................................................................................. 10
3.3.1. Target Regulator.......................................................................................................... 10
3.3.2. External Supply............................................................................................................11
3.3.3. VBUS Output Pin......................................................................................................... 11
3.4. Target Current Measurement..................................................................................................... 12
3.5. Disconnecting the On-Board Debugger..................................................................................... 13
4. Hardware User Guide..............................................................................................15
4.1. Connectors.................................................................................................................................15
4.1.1. ATtiny1607 Curiosity Nano Pinout............................................................................... 15
4.1.2. Using Pin Headers.......................................................................................................15
4.2. Peripherals................................................................................................................................. 16
4.2.1. LED..............................................................................................................................16
4.2.2. Mechanical Switch.......................................................................................................16
4.2.3. On-Board Debugger Implementation...........................................................................16
4.2.3.1. On-Board Debugger Connections............................................................. 16
5. Hardware Revision History and Known Issues........................................................18
5.1. Identifying Product ID and Revision........................................................................................... 18
5.2. Chip Erase at Low Voltage.........................................................................................................18
5.3. Revision 2...................................................................................................................................18
5.4. Revision 1...................................................................................................................................18
6. Document Revision History..................................................................................... 20
ATtiny1607 Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 2

7. Appendix..................................................................................................................21
7.1. Schematic...................................................................................................................................21
7.2. Assembly Drawing......................................................................................................................23
7.3. Curiosity Nano Base for Click boards™...................................................................................... 24
7.4. Connecting External Debuggers................................................................................................ 25
7.5. Getting Started with IAR.............................................................................................................26
The Microchip Website..................................................................................................29
Product Change Notification Service.............................................................................29
Customer Support......................................................................................................... 29
Microchip Devices Code Protection Feature................................................................. 29
Legal Notice...................................................................................................................30
Trademarks................................................................................................................... 30
Quality Management System........................................................................................ 31
Worldwide Sales and Service........................................................................................32
ATtiny1607 Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 3

1. Introduction
1.1 Features
• ATtiny1607-MNR Microcontroller
• One Yellow User LED
• One Mechanical User Switch
• On-Board Debugger
– Board identification in Atmel Studio/Microchip MPLAB® X
– One green power and status LED
– Programming and debugging
– Virtual COM port (CDC)
– Two logic analyzer 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 Kit Overview
The Microchip ATtiny1607 Curiosity Nano evaluation kit is a hardware platform to evaluate the
ATtiny1607 microcontroller.
Figure 1-1. ATtiny1607 Curiosity Nano Evaluation Kit Overview
ATtiny1607 Curiosity Nano
Introduction
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 4

2. Getting Started
2.1 Curiosity Nano Quick Start
Steps to start exploring the Curiosity Nano platform:
1. Download Atmel Studio/Microchip MPLAB® X.
2. Launch Atmel Studio/Microchip MPLAB® X.
3. Connect a USB cable (Standard-A to Micro-B or Micro-AB) between the PC and the debug USB
port on the kit.
When the Curiosity Nano kit 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 kit are
included with Atmel Studio/Microchip MPLAB® X.
Once the Curiosity Nano board is powered the green status LED will be lit and Atmel Studio/Microchip
MPLAB® X will auto-detect which Curiosity Nano board is connected. Atmel Studio/Microchip MPLAB® X
will present relevant information like data sheets and kit documentation. The ATtiny1607 device is
programmed by the on-board debugger and therefore no external programmer tool is required.
2.2 Design Documentation and Relevant Links
The following list contains links to the most relevant documents and software for the ATtiny1607 Curiosity
Nano.
•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.
•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 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
8-bit AVR. There is a 30-day evaluation version as well as a 4 KB code-size-limited kick-start version
available from their website.
•Atmel START - Atmel START is an online tool that 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.
•Data Visualizer - Data Visualizer is a program used for processing and visualizing data. The Data
Visualizer can receive data from various sources such as the EDBG Data Gateway Interface found
on Curiosity Nano and Xplained Pro boards and COM Ports.
•ATtiny1607 Curiosity Nano website - Kit information, latest user guide and design documentation.
•ATtiny1607 Curiosity Nano on Microchip Direct - Purchase this kit on Microchip Direct.
ATtiny1607 Curiosity Nano
Getting Started
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 5

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 Atmel Studio/Microchip MPLAB® X. Each board is identified in the IDE, and
relevant user guides, application notes, data sheets, and example code are easy to find. The on-board
debugger features a Virtual COM port (CDC) for serial communication to a host PC, and a Data Gateway
Interface (DGI) GPIO logic analyzer pin.
3.1 On-board Debugger
ATtiny1607 Curiosity Nano contains an on-board debugger for programming and debugging. The on-
board debugger is a composite USB device of several interfaces: A debugger, a mass storage device, a
data gateway, and a Virtual COM port (CDC).
Together with Atmel Studio/Microchip MPLAB® X, the on-board debugger can program and debug the
ATtiny1607.
A Data Gateway Interface (DGI) is available for use with the logic analyzer channels for code
instrumentation, to visualize the program flow. DGI GPIOs can be graphed using the Data Visualizer.
The Virtual COM port is connected to a UART on the ATtiny1607 and provides an easy way to
communicate with the target application through terminal software.
The on-board debugger controls a Power and Status LED (marked PS) on ATtiny1607 Curiosity Nano.
The table below shows how the LED is controlled in different operation modes.
Table 3-1. On-Board Debugger LED Control
Operation Mode Status LED
Boot Loader mode LED blink at 1 Hz during power-up.
Power-up LED is ON.
Normal operation LED is ON.
Programming Activity indicator: The LED flashes slowly during programming/debugging.
Fault The LED flashes fast if a power fault is detected.
Sleep/Off LED is off. The on-board debugger is either in Sleep mode or powered down.
This can occur if the kit is externally powered.
3.1.1 Virtual COM Port
The Virtual COM Port is a general purpose serial bridge between a host PC and a target device.
3.1.1.1 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 COM Port. The CDC can be used
to stream arbitrary data in both directions between the host and the target: All characters sent from the
host will be sent through a UART on the CDC TX pin, and UART characters sent into the CDC RX pin will
be sent back to the host through the Virtual COM Port.
On Windows machines, the CDC will enumerate as Curiosity Virtual COM Port and appear in the Ports
section of the device manager. The COM port number is shown here.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 6

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#.
Info: On older Windows systems, a USB driver is required for CDC. This driver is included in
MPLAB X and Atmel® Studio installations.
3.1.1.2 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 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.
3.1.1.3 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. This is a virtual control signal
implemented on the USB interface, but not in hardware in the on-board debugger. Asserting DTR from
the host will indicate to the on-board debugger that a CDC session is active, will enable its level shifters
(if available) and start the CDC data send and receive mechanisms.
Deasserting the DTR signal will not disable the level shifters but disable the receiver so no further data
will be streamed to the host. Data packets that are already queued up for sending to the target will
continue to be sent out, but no further data will be accepted.
Remember: Enable to set up your terminal emulator to assert the DTR signal. Without it, the
on-board debugger will not send or receive any data through its UART.
3.1.1.4 Advanced Use
CDC Override Mode
In normal operation, the on-board debugger is a true UART bridge between the host and the device.
However, under certain use cases, the on-board debugger can override the basic operating mode and
use the CDC pins for other purposes.
Dropping a text file (with extension .txt) into the on-board debugger’s mass storage drive can be used
to send characters out of the CDC TX pin. The text file must start with the characters:
CMD:SEND_UART=
The maximum message length is 50 characters - all remaining data in the frame are ignored.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 7

The default baud rate used in this mode is 9600 bps, but if the CDC is already active or has been
configured, the baud rate last used still applies.
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 CDC TX pin. Transferring a small
amount of data per frame can be inefficient, particularly at low baud rates, since the on-board debugger
buffers frames and not bytes. A maximum of 4 x 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.
When receiving data from the target, 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 8 x 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
frame of data 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.
3.1.2 Mass Storage Disk
A simple way to program the target device is through drag and drop with .hex files.
3.1.2.1 Mass Storage Device
The on-board debugger implements a highly optimized variant of the FAT12 file system that has a number
of limitations, partly due to the nature of FAT12 itself and optimizations made to fulfill its purpose for its
embedded application.
The CURIOSITY drive is USB Chapter 9 compliant as a mass storage device but does not, in any way,
fulfill the expectations of a general purpose mass storage device. This behavior is intentional.
The on-board debugger enumerates as a Curiosity Nano USB device that can be found in the disk drives
section of the Windows device manager. The CURIOSITY drive appears in the file manager and claims
the next available drive letter in the system.
The CURIOSITY drive contains approximately one MB of free space. This does not reflect the size of the
target device's Flash in any way. When programming a .hex file, the binary data are encoded in ASCII
with metadata providing a large overhead, so one MB is a trivially chosen value for disk size.
It is not possible to format the CURIOSITY drive. When programming a file to the target, the filename may
appear in the disk directory listing. This is merely the operating system's view of the directory, which, in
reality, has not been updated. It is not possible to read out the file contents. Removing and replugging the
kit will return the file system to its original state, but the target will still contain the application that has
been previously programmed.
To erase the target device, copy a text file starting with “CMD:ERASE” onto the disk.
By default, the CURIOSITY drive contains several read-only files for generating icons as well as reporting
status and linking to further information:
•AUTORUN.ICO - icon file for the Microchip logo.
•AUTORUN.INF - system file required for Windows Explorer to show the icon file.
•KIT-INFO.HTM - redirect to the development board website.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 8

•KIT-INFO.TXT - a text file containing details about the kit firmware, name, serial number, and
device.
•STATUS.TXT - a text file containing the programming status of the board.
Info: STATUS.TXT is dynamically updated by the on-board debugger, the contents may be
cached by the OS and therefore not reflect the correct status.
3.1.2.2 Fuse Bytes
Fuse Bytes (AVR® MCU Targets)
The debugger does not mask any fuse bits or combinations when writing fuses. It is not possible to
disable UPDI by fuse setting on devices with a dedicated UPDI pin. For devices with a shared/
configurable UPDI pin, be sure not to select an alternate pin function for UPDI either by fuse setting in
Programming mode or by using the I/O view or memory views to modify the memory-mapped fuse
values. Disabling UPDI will render the debugger unable to contact the target device — an external
programmer capable of 12V UPDI activation will be required.
3.2 Curiosity Nano Standard Pinout
The twelve edge connections closest to the USB connector on Curiosity Nano kits have a standardized
pinout. The program/debug pins have different functions depending on the target programming interface
as shown in the table and figure below.
Table 3-2. Curiosity Nano Standard Pinout
Debugger Signal UPDI Target Description
ID - ID line for extensions.
CDC TX UART RX USB CDC TX line.
CDC RX UART TX USB CDC RX line.
DBG0 UPDI Debug data line.
DBG1 GPIO1 Debug clock line/DGI GPIO.
DBG2 GPIO0 DGI GPIO.
DBG3 RESET Reset line.
NC - No connect.
VBUS - VBUS voltage for external use.
VOFF - Voltage Off input.
VTG - Target voltage.
GND - Common ground.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 9

Figure 3-1. Curiosity Nano Standard Pinout
USB
DEBUGGER
PS LED
NC
NC
ID
ID
CDC RX
CDCRX
CDC TX
CDCTX
DBG1
DBG1
DBG2
DBG2
VBUS
VBUS
VOFF
VOFF
DBG3
DBG3
DBG0
DBG0
GND
GND
VTG
VTG
CURIOSITY NANO
3.3 Power Supply
The kit is powered through the USB port and contains two LDO regulators, one to generate 3.3V for the
on-board debugger, and an adjustable LDO regulator for the target microcontroller ATtiny1607 and its
peripherals. The voltage from the USB connector can vary between 4.4V to 5.25V (according to the USB
specification) and will limit the maximum voltage to the target. The figure below shows the entire power
supply system on ATtiny1607 Curiosity Nano.
Figure 3-2. Power Supply Block Diagram
USB
Target
MCU
Power source
Cut strap
Power consumer P3V3 DEBUGGER
Power converter
DEBUGGER
Regulator
VUSB
Target
Regulator
Power
Supply
strap
Adjust
Level
shifter
VLVL
VREG
I/O I/O GPIO
straps
I/O
On/Off
Measure On/Off
ID system
#VOFF
PTC
Fuse
Power protection
VBUS
Target
Power
strap
VTG
3.3.1 Target Regulator
The target voltage regulator is a MIC5353 variable output LDO. The on-board debugger can adjust the
voltage output supplied to the kit target section by manipulating the MIC5353's feedback voltage. The
hardware implementation is limited to an approximate voltage range from 1.7V to 5.1V. Additional output
voltage limits are configured in the debugger firmware to ensure that the output voltage never exceeds
the hardware limits of the ATtiny1607 microcontroller. The voltage limits configured in the on-board
debugger on ATtiny1607 Curiosity Nano are 1.8-5.1V.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 10

Info: The target voltage is set to 3.3V in production. It can be changed through MPLAB X
project properties, and in the Atmel Studio device programming dialog. Any change to the target
voltage is persistent, even through a power toggle.
The MIC5353 supports a maximum current load of 500 mA. It is an LDO regulator in a small package,
placed on a small PCB, and the thermal shutdown condition can be reached at lower loads than 500 mA.
The maximum current load depends on the input voltage, the selected output voltage, and the ambient
temperature. The figure below shows the safe operating area for the regulator, with an input voltage of
5.1V and an ambient temperature of 23°C.
Figure 3-3. Target Regulator Safe Operation Area
3.3.2 External Supply
ATtiny1607 Curiosity Nano can be powered by an external voltage instead of the on-board target
regulator. When the Voltage Off (VOFF) pin is shorted to ground (GND) the on-board debugger firmware
disables the target regulator, and it is safe to apply an external voltage to the VTG pin.
WARNING
Applying an external voltage to the VTG pin without shorting VOFF to GND may cause
permanent damage to the kit.
WARNING
Absolute maximum external voltage is 5.5V for the on-board level shifters, and the standard
operating condition of the ATtiny1607 is 1.8-5.5V. Applying a higher voltage may cause
permanent damage to the kit.
Programming, debugging, and data streaming is still possible with an external power supply: The
debugger and signal level shifters will be powered from the USB cable. Both regulators, the debugger,
and the level shifters are powered down when the USB cable is removed.
3.3.3 VBUS Output Pin
ATtiny1607 Curiosity Nano has a VBUS output pin which can be used to power external components that
need a 5V supply. The VBUS output pin has a PTC fuse to protect the USB against short circuits. A side
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 11

effect of the PTC fuse is a voltage drop on the VBUS output with higher current loads. The chart below
shows the voltage versus the current load of the VBUS output.
Figure 3-4. VBUS Output Voltage vs. Current
3.4 Target Current Measurement
Power to the ATtiny1607 is connected from the on-board power supply and VTG pin through a 100-mil pin
header cut Target Power strap marked with “POWER” in silkscreen (J101). To measure the power
consumption of the ATtiny1607 and other peripherals connected to the board, cut the Target Power Strap
and connect an ammeter over the strap.
Figure 3-5. Target Power Strap
Target Power strap (top side)
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 12

Tip: A 100-mil pin header can be soldered into the Target Power strap (J101) footprint for easy
connection of an ammeter. Once the ammeter is not needed anymore, place a jumper-cap on
the pin header.
Info: The on-board level shifters will draw a small amount of current even when they are not in
use. A maximum of 10 µA can be drawn from the target power net, and an additional 2 µA can
be drawn from each I/O pin connected to a level shifter for a total of 20 µA. Disconnect the on-
board debugger and level shifters as described in Section 3.5 Disconnecting the On-Board
Debugger and keep any I/O pin connected to a level shifter in tri-state to prevent leakage.
3.5 Disconnecting the On-Board Debugger
The block diagram below shows all connections between the debugger and the ATtiny1607
microcontroller. The rounded boxes represent connections to the board edge on ATtiny1607 Curiosity
Nano. The signal names shown in Figure 3-1 are printed in silkscreen on the bottom side of the board.
Figure 3-6. On-Board Debugger Connections to the ATtiny1607
DEBUGGER
TARGETLevel-Shift
PA04/PA06
PA07
PA08
PA16
PA00
PA01
USB
DIR x 5
VCC_P3V3
VBUS
VCC_LEVEL
VCC_TARGET
DBG0
DBG1
DBG2
DBG3
CDC TX
CDC RX
CDC RX
CDCTX
DBG3
DBG2
DBG1
DBG0
GPIO straps
LDO
VOFF
LDO
VBUS VTG
VCC_EDGE
Power Supply strap Target Power strap
By cutting the GPIO straps with a sharp tool, as shown in Figure 3-7, all I/Os connected between the
debugger and the ATtiny1607 are completely disconnected. To completely disconnect the target regulator
and level shifter power from the target, cut the Power Supply strap (J100) as shown in Figure 3-7.
Info: Cutting the connections to the debugger will disable programming, debugging, data
streaming, and the target power supply. The signals will also be disconnected from the board
edge next to the on-board debugger section.
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 13

Tip: Solder in 0Ω resistors across the footprints or short-circuit them with tin solder to
reconnect any cut signals.
Figure 3-7. Kit Modifications
GPIO straps (bottom side) Power Supply strap (top side)
ATtiny1607 Curiosity Nano
Curiosity Nano
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 14

4. Hardware User Guide
4.1 Connectors
4.1.1 ATtiny1607 Curiosity Nano Pinout
All the ATtiny1607 I/O pins are accessible at the edge connectors on the board. The image below shows
the kit pinout.
Figure 4-1. ATtiny1607 Curiosity Nano Pinout
USB
DEBUGGER
ATtiny1607
SW0
LED0
PS LED
NC
NC
ID
ID
CDC RX
CDC RX
PB2
CDC TX
CDC TX
PB3
DBG1
DBG1
PB7LED0
DBG2
DBG2
PC4SW0
PA1
PA1
TX1
PA2
PA2
RX1
PB1
PB1
SDA
PB0
PB0
SCL
PC2
PC2
MOSI
PC1
PC1
MISO
PC0
PC0
SCK
PC3
PC3
SS
GND
GND
PB2
PB2
TXD
PB3
PB3
RXD
VBUS
VBUS
VOFF
VOFF
DBG3
DBG3
DBG0
DBG0
PA0 UPDI
GND
GND
VTG
VTG
PB6
PB6
PB5
PB5
PB4
PB4
PA3
PA3
PA4
PA4
PA5
PA5
PA6
PA6
PA7
PA7
GND
GND
PC5
PC5
PC4
PC4
SW0
ATtiny1607
CURIOSITY NANO
Analog
Debug
I2C
SPI
UART
Shared pinout
Peripheral
Port
PWM
Power
Ground
4.1.2 Using Pin Headers
The edge connector footprint on ATtiny1607 Curiosity Nano has a staggered design where each of the
holes is shifted 8 mil (~0.2 mm) off center. The hole shift allows the use of regular 100-mil pin headers on
the kit without soldering. Once the pin headers are firmly in place, they can be used in normal
applications like pin sockets and prototyping boards without any issues.
Tip: Start at one end of the pin header and gradually insert the header along the length of the
board. Once all the pins are in place, use a flat surface to push them all the way in.
ATtiny1607 Curiosity Nano
Hardware User Guide
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 15

Tip: For applications where the pin headers will be used permanently, it is still recommended
to solder them in place.
Important: Once the pin headers are in place, they are hard to remove by hand. Use a set of
pliers and carefully remove the pin headers to avoid damage to the pin headers and printed
circuit board.
4.2 Peripherals
4.2.1 LED
There is one yellow user LED available on the ATtiny1607 Curiosity Nano kit that can be controlled by
either GPIO or PWM. The LED can be activated by driving the connected I/O line to GND.
Table 4-1. LED Connection
ATtiny1607 Pin Function Shared Functionality
PB7 Yellow LED0 Edge connector
4.2.2 Mechanical Switch
ATtiny1607 Curiosity Nano has one mechanical switch. This is a generic user configurable switch. When
the switch is pressed, it will drive the I/O line to ground (GND).
Tip: There is no externally connected pull-up resistor on the switch. To use the switch, make
sure that an internal pull-up resistor is enabled on pin PC4.
Table 4-2. Mechanical Switch
ATtiny1607 Pin Description Shared Functionality
PC4 User switch (SW0) Edge connector
4.2.3 On-Board Debugger Implementation
ATtiny1607 Curiosity Nano features an on-board debugger that can be used to program and debug the
ATtiny1607 using UPDI. The on-board debugger also includes a Virtual Com port interface over UART
and DGI GPIO. Atmel Studio/Microchip MPLAB® X can be used as a front-end for the on-board debugger
for programming and debugging. Data Visualizer can be used as a front-end for the CDC and DGI GPIO.
4.2.3.1 On-Board Debugger Connections
The table below shows the connections between the target and the debugger section. All connections
between the target and the debugger are tri-stated as long as the debugger is not actively using the
interface. Hence there is little contamination of the signals the pins can be configured to anything the user
wants.
For further information on how to use the capabilities of the on-board debugger, see Section 3. Curiosity
Nano.
ATtiny1607 Curiosity Nano
Hardware User Guide
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 16

Table 4-3. On-Board Debugger Connections
ATtiny1607 Pin Debugger Pin Function Shared Functionality
PB3 CDC TX UART RX (ATtiny1607 RX line) Edge connector
PB2 CDC RX UART TX (ATtiny1607 TX line) Edge connector
UPDI DBG0 UPDI
PB7 DBG1 GPIO Edge connector
PC4 DBG2 GPIO Edge connector
UPDI DBG3 RESET (J202, not connected by
default)
Edge connector
ATtiny1607 Curiosity Nano
Hardware User Guide
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 17

5. Hardware Revision History and Known Issues
This user guide provides the latest available revision of the kit. This section contains information about
known issues, a revision history of older revisions, and how older revisions differ from the latest revision.
5.1 Identifying Product ID and Revision
The revision and product identifier of the ATtiny1607 Curiosity Nano can be found in two ways; either
through Atmel Studio/Microchip MPLAB® X or by looking at the sticker on the bottom side of the PCB.
By connecting a ATtiny1607 Curiosity Nano to a computer with Atmel Studio/Microchip MPLAB® X
running, an information window will pop up. The first six digits of the serial number, which is listed under
kit details, contain the product identifier and revision.
The same information can be found on the sticker on the bottom side of the PCB. Most kits will print the
identifier and revision in plain text as A09-nnnn\rr, where “nnnn” is the identifier and “rr” is the revision.
The boards with limited space have a sticker with only a QR-code, containing the product identifier,
revision and the serial number.
The serial number string has the following format:
"nnnnrrssssssssss"
n = product identifier
r = revision
s = serial number
The product identifier for ATtiny1607 Curiosity Nano is A09-3252.
5.2 Chip Erase at Low Voltage
This kit supports variable voltage from 1.8-5.1V. When a chip erase of the ATtiny1607 is started, the BOD
is enabled and uses the BODLEVEL set in the FUSE.BODCFG fuse byte. If the BODLEVEL is set higher
than the selected target voltage on the kit, chip erase will fail.
Info: BODLEVEL0 in the ATtiny1607 has a maximum trigger voltage of 2.0V, which means that
chip erase is likely to fail if the kit voltage is set to 1.8V.
5.3 Revision 2
Revision 2 adds the Target Power strap and staggers the holes along the edge of the PCB for convenient
use of pin headers without soldering.
5.4 Revision 1
Revision 1 is the initially released revision with limited distribution.
ATtiny1607 Curiosity Nano
Hardware Revision History and Known Issues
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 18

The holes along the edge of revision 1 are not staggered as described in Using Pin Headers and requires
that any pin headers must be soldered into the board for use.
Revision 1 does not have the Target Power strap described in 3.4 Target Current Measurement. Instead,
the current can be measured across the Power Supply strap, as described in 3.5 Disconnecting the On-
Board Debugger.
Figure 5-1. ATtiny1607 Curiosity Nano Revision 1
ATtiny1607 Curiosity Nano
Hardware Revision History and Known Issues
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 19

6. Document Revision History
Doc. rev. Date Comment
A 06/2019 Initial document release.
ATtiny1607 Curiosity Nano
Document Revision History
© 2019 Microchip Technology Inc. User Guide DS50002897A-page 20