Microchip Technology AVR128DB48 Curiosity Nano, Руководство пользователя по оборудованию

Страница: 29 / 46

...........continued
OPAMP Poisitive Input (INP) Negative Input (INN) Output (OUT)
OP2 PE1 PE3 PE2
For information about OPAMP on the edge connector and any shared functionality, see 5.1.1 AVR128DB48 Curiosity
Nano Pinout .
5.2 Peripherals
5.2.1 LED
There is one yellow user LED available on the AVR128DB48 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 5-2. LED Connection
AVR128DB48 Pin Function Shared Functionality
PB3 Yellow LED0 Edge connector , On-board debugger
5.2.2 Mechanical Switch
The AVR128DB48 Curiosity Nano board 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 PB2.
Table 5-3. Mechanical Switch
AVR128DB48 Pin Description Shared Functionality
PB2 User switch (SW0) Edge connector , On-board debugger
5.2.3 32.768 kHz Crystal
On the AVR128DB48 Curiosity Nano board is a mounted 32.768 kHz crystal of type VMK3-9001-32K7680000 , the
crystal is accurate to within 20 ppm. Using the External 32.768 kHz Crystal Oscillator (XOSC32K) module in
AVR128DB48 with the mounted 32.768 kHz crystal generates a clock signal that is significantly more accurate than
the Internal 32.768 kHz Ultra Low-Power Oscillator (OSC32K) module can generate alone. With the Auto-Tune
feature, the 32.768 kHz can be used as a reference to improve the accuracy of the internal oscillator. This is an ideal
reference clock for the Real-Time Counter module in AVR128DB48.
The 32.768 kHz crystal is connected to AVR128DB48 on PF0 and PF1, which are also routed to the edge connector
through two solder points. PF0 and PF1 are disconnected from the edge connector by default to reduce the chance
of an external signal causing contention with the crystal, and to remove excessive capacitance on the lines.
Next to the 32.768 kHz crystal is a cut-strap (J209), which can be used to measure the oscillator safety factor. This is
done by cutting the strap and adding a 0402 SMD resistor across the strap. More information about oscillator
allowance and safety factor can be found in the
AN2648 application note from Microchip.
Cut straps and solder points can be seen in Figure 5-5 .
Table 5-4. 32.768 kHz Crystal Connections
AVR128DB48 Pin Function Shared Functionality
PF0 XTAL32K1 (Crystal input) Edge connector
AVR128DB48 Curiosity Nano
Hardware User Guide
©
2020 Microchip Technology Inc.
User Guide
DS50003037A-page 29