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 PCB.
4.2
Peripherals
4.2.1
LED
There is one yellow user LED available on the ATtiny3217 Curiosity Nano Board 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
ATtiny3217 Pin
Function
Shared Functionality
PA3
Yellow LED0
4.2.2
Mechanical Switch
The ATtiny3217 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 PB7.
Table 4-2. Mechanical Switch
ATtiny3217 Pin
Description
Shared Functionality
PB7
User switch (SW0)
4.2.3
Crystal
The ATtiny3217 Curiosity Nano Board has a 32.768 kHz crystal footprint made for standard 3.2mm by 1.5mm surface
mount crystals with two terminals.
The crystal footprint is not connected to the ATtiny3217 by default, as the GPIOs are routed out to the edge
connector. To use the crystal, some hardware modifications are required. The two I/O lines routed to the edge
connector must be disconnected to reduce the chance of contention to the crystal, and to remove excessive
capacitance on the lines. This can be done by cutting the two straps on the bottom side of the board, marked PB2
and PB3 as shown in the figure below. Next, short circuit each of the circular solder points next to the crystal on the
top side of the board, the easiest way is to solder a solder tin blob across the footprint.
ATtiny3217
Hardware User Guide
©
2020 Microchip Technology Inc.
User Guide
DS40002193A-page 25
