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SAM4CP [DATASHEET]
43051E–ATPL–08/14
32.4
Product Dependencies
32.4.1 Pin Multiplexing
Each pin is configurable, depending on the product, as either a general-purpose I/O line only, or as an I/O line
multiplexed with one or two peripheral I/Os. As the multiplexing is hardware defined and thus product-dependent, the
hardware designer and programmer must carefully determine the configuration of the PIO Controllers required by their
application. When an I/O line is general-purpose only, i.e. not multiplexed with any peripheral I/O, programming of the
PIO Controller regarding the assignment to a peripheral has no effect and only the PIO Controller can control how the pin
is driven by the product.
32.4.2 Power Management
The Power Management Controller controls the peripheral clock in order to save power. Writing any of the registers of
the user interface does not require the peripheral clock to be enabled. This means that the configuration of the I/O lines
does not require the peripheral clock to be enabled.
However, when the clock is disabled, not all of the features of the PIO Controller are available, including glitch filtering.
Note that the input change interrupt, the interrupt modes on a programmable event and the read of the pin level require
the clock to be validated.
After a hardware reset, the peripheral clock is disabled by default.
The user must configure the Power Management Controller before any access to the input line information.
32.4.3 Interrupt Generation
For interrupt handling, the PIO Controllers are considered as user peripherals. This means that the PIO Controller
interrupt lines are connected among the interrupt sources. Refer to the PIO Controller peripheral identifier in the
Peripheral Identifiers table to identify the interrupt sources dedicated to the PIO Controllers. Using the PIO Controller
requires the Interrupt Controller to be programmed first.
The PIO Controller interrupt can be generated only if the peripheral clock is enabled.