SAM4L Datasheet, PDF (197/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
13.4 I/O Lines Description
Table 13-1. I/O Lines Description
Pin Name
Pin Description
XIN
Crystal Input
XOUT
Crystal Output
GCLK3-GCLK0
Generic Clock Output
GCLK_IN1-GCLK_IN0
Generic Clock Input
Type
Analog/Digital
Analog
Output
Input
13.5 Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
13.5.1 I/O Lines
The SCIF provides a number of generic clock outputs, which can be connected to output pins,
multiplexed with GPIO lines. The user must first program the GPIO controller to assign these
pins to their peripheral function. If the I/O pins of the SCIF are not used by the application, they
can be used for other purposes by the GPIO controller. Oscillator pins are also multiplexed with
GPIO. When oscillators are used, the related pins are controlled directly by the SCIF, overriding
GPIO settings.
13.5.2
Power Management
Oscillators are turned off in some Power Save modes and turned automatically on when the
device wakes up.
13.5.3 Clocks
The SCIF controls some oscillators in the device. The oscillators can be used as source for the
CPU and peripherals, selection of source is done in the Power Manager. The oscillator can also
be used as source for generic clocks.
13.5.4 Interrupts
The SCIF interrupt request line is connected to the NVIC. Using the SCIF interrupt requires the
NVIC to be programmed first.
13.5.5
Debug Operation
The SCIF does not interact with debug operations.
13.6 Functional Description
13.6.1
Oscillator (OSC) Operation
Rev: 1.1.4.0
The main oscillator (OSCn) is designed to be used with an external 0.6 to 30MHz crystal and
two biasing capacitors, as shown in the Electrical Characteristics chapter, or with an external
clock connected to the XIN. The oscillator can be used as source for the main clock in the
device, as described in the Power Manager chapter. The oscillator can be used as source for the
generic clocks, as described in the Generic Clocks section.
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