NRF52820-QDAA-R datasheet(136/437 Pages) NORDIC

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Peripherals

Tasks and events are configured using the CONFIG[n] registers. One CONFIG[n] register is associated with a

set of SET[n], CLR[n], and OUT[n] tasks and IN[n] events.

As long as a SET[n], CLR[n], and OUT[n] task or an IN[n] event is configured to control pin n, the pin's

output value will only be updated by the GPIOTE module. The pin's output value, as specified in the GPIO,

will be ignored as long as the pin is controlled by GPIOTE. Attempting to write to the pin as a normal GPIO

pin will have no effect. When the GPIOTE is disconnected from a pin, the associated pin gets the output

and configuration values specified in the GPIO module, see MODE field in CONFIG[n] register.

When conflicting tasks are triggered simultaneously (i.e. during the same clock cycle) in one channel, the

priority of the tasks is as described in the following table.

Priority

Task

OUT

CLR

SET

Table 42: Task priorities

When setting the CONFIG[n] registers, MODE=Disabled does not have the same effect as MODE=Task and

POLARITY=None. In the latter case, a CLR or SET task occurring at the exact same time as OUT will end up

with no change on the pin, based on the priorities described in the table above.

When a GPIOTE channel is configured to operate on a pin as a task, the initial value of that pin is

configured in the OUTINIT field of CONFIG[n].

6.9.2 Port event

PORT is an event that can be generated from multiple input pins using the GPIO DETECT signal.

The event will be generated on the rising edge of the DETECT signal. See GPIO — General purpose input/

output on page 127 for more information about the DETECT signal.

The GPIO DETECT signal will not wake the system up again if the system is put into System ON IDLE while

the DETECT signal is high. Clear all DETECT sources before entering sleep. If the LATCH register is used as

a source, a new rising edge will be generated on DETECT if any bit in LATCH is still high after clearing all

or part of the register. This could occur if one of the PINx.DETECT signals is still high, for example. See Pin

configuration on page 128 for more information.

Setting the system to System OFF while DETECT is high will cause a wakeup from System OFF reset.

This feature is always enabled even if the peripheral itself appears to be IDLE, meaning no clocks or

other power intensive infrastructure have to be requested to keep this feature enabled. This feature can

therefore be used to wake up the CPU from a WFI or WFE type sleep in System ON when all peripherals

and the CPU are idle, meaning the lowest power consumption in System ON mode.

In order to prevent spurious interrupts from the PORT event while configuring the sources, the following

must be performed:

1. Disable interrupts on the PORT event (through INTENCLR.PORT).

2. Configure the sources (PIN_CNF[n].SENSE).

3. Clear any potential event that could have occurred during configuration (write '0' to EVENTS_PORT).

4. Enable interrupts (through INTENSET.PORT).

6.9.3 Tasks and events pin configuration

Each GPIOTE channel is associated with one physical GPIO pin through the CONFIG.PSEL field.

When Event mode is selected in CONFIG.MODE, the pin specified by CONFIG.PSEL will be configured

as an input, overriding the DIR setting in GPIO. Similarly, when Task mode is selected in CONFIG.MODE,

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NRF52820-QDAA-R Datasheet(PDF) 136 Page - Nordic Semiconductor

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