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Debugger Signal

Target MCU

Description

NC

—

No connect

VBUS

—

VBUS voltage for external use

VOFF

—

Voltage Off input. Disables the target regulator and

target voltage when pulled low.

VTG

—

Target voltage

GND

—

Common ground

Figure 3-3. Curiosity Nano Standard Pinout

USB

DEBUGGER

PS LED

NC

ID

CDC RX

CDC TX

DBG1

DBG2

VBUS

VOFF

DBG3

DBG0

GND

VTG

CURIOSITY NANO

3.3

Power Supply

The board 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 ATtiny1627 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 ATtiny1627 Curiosity

Nano.

Figure 3-4. 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

ATtiny1627

Curiosity Nano

© 2020 Microchip Technology Inc.

User Guide

DS40002199A-page 14