Atmel SAM L22 Xplained Pro, Руководство пользователя

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Info: There is no pull-up resistor connected to the generic user button. Remember to enable
the internal pull-up in the SAM L22 to use the button.
Table 4-13. Mechanical Buttons
SAM L22 pin Silkscreen text Shared functionality
RESET RESET
PC01 SW0 EXT2 , Shield , and EDBG GPIO3
4.3.3. LED
There is one yellow LED available on the SAM L22 Xplained Pro board that can be turned ON and OFF.
The LED can be activated by driving the connected I/O line to GND.
Table 4-14. LED Connection
SAM L22 pin Function Shared functionality
PC27 Yellow LED0 SLCD
4.3.4. QTouch Button
There is one self capacitance button available on the SAM L22 Xplained Pro board that can be used as
I/O. This QTouch button is intended to be driven by the built-in Peripheral Touch Controller (PTC) of the
device.
Info: To get started with QTouch, refer to Atmel QTouch
®
Library and Atmel QTouch
®
Composer .
Table 4-15. QTouch Connection
SAM L22 pin Silkscreen text Shared functionality
PB06 QT BTN1 SLCD
4.3.5. Backup Super Capacitor
The SAM L22 Xplained Pro has a backup super capacitor for use with the SAM L22 backup system. The
super capacitor can be connected to the device by placing a jumper over pin 1-2 on the 3-pin VBAT
SELECT header.
By default the jumper is placed over pin 2-3 to select the board power supply. This configuration is
selected to avoid draining the super capacitor and can be used during development.
Due to the high capacitive load represented by the super capacitor, a 220Ω limiting resistor is added to
reduce inrush current. The charging supply is the targets main supply and a low-power opamp is used for
disconnecting the charger input when removing power. This is added to avoid a current leak back to the
main supply from the super capacitor when power is removed.
A full charge of the super capacitor from empty will take approximately 45 seconds and can supply the
target device in backup mode with ULP running for up to 24 hours. Other modes are not characterized,
but will reduce the available time in backup mode respectively. For more information about the current
consumption in other modes, refer to the electrical characteristics chapter in the SAM L22 datasheet.
Atmel SAM L22 Xplained Pro [USER GUIDE]
Atmel-42474B-SAM-L22-Xplained-Pro_User Guide-12/2015
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