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2014-07-02 - Gecko Family - d0001_Rev1.30
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function’s output data and output enable signals override the data output and output enable signals
from the GPIO. However, the pin configuration stays as set in GPIO_Px_MODEL, GPIO_Px_MODEH
and GPIO_Px_DOUT registers. I.e. the pin configuration must be set to output enable in GPIO for a
peripheral to be able to use the pin as an output.
It is possible, but not recommended to select two or more peripherals as output on the same pin. These
signals will then be OR'ed together. However, TIMER CCx and CDTIx outputs, which are routed as
alternate functions, have priority, and will never be OR'ed with other alternate functions. The reader is
referred to the pin map section of the device datasheet for more information on the possible locations
of each alternate function and any priority settings.
28.3.2.1 Serial Wire Debug Port Connection
The SW Debug Port is routed as an alternate function and the SWDIO and SWCLK pin connections
are enabled by default with internal pull-up and pull-down resistors, respectively. It is possible to disable
these pin connections (and disable the pull resistors) by setting the SWDIOPEN and SWCLKPEN bits
in GPIO_ROUTE to 0.
WARNING: When the debug pins are disabled, the device can no longer be accessed by a debugger. A
reset will set the debug pins back to their default state as enabled. If you do disable the debug pins, make
sure you have at least a 3 second timeout at the start of your program code before you disable the debug
pins. This way the debugger will have time to halt the device after a reset before the pins are disabled.
The Serial Wire Viewer Output pin (SWO) can be enabled by setting the SWOPEN bit in GPIO_ROUTE.
This bit can also be routed to alternate locations by configuring the LOCATION bitfield in GPIO_ROUTE.
28.3.2.2 Analog Connections
When using the GPIO pin for analog functionality, it is recommended to disable the digital output and
set the MODEn in GPIO_Px_MODEL/GPIO_Px_MODEH equal to 0b0000 to disable the input sense
and pull resistors.
28.3.3 Interrupt Generation
The GPIO can generate an interrupt from the input of any GPIO pin on a device. The interrupts have
asynchronous sense capability, enabling wake-up from energy modes as low as EM3, see Figure 28.5 (p.
429) .
Figure 28.5. Pin n Interrupt Generation
IRQ_GPIO_EVEN/
IRQ_GPIO_ODD
PAn
EXTIRISE[n]
IEN[n]
EXTIPSELn[2:0]
PBn
PCn
PDn
PEn
IF[n]
set
clear
IFS[n]
IFC[n]
wakeup
PFn
EXTIFALL[n]
PRS
Odd/ even input s
Synch
All pins with the same pin number (n) are grouped together to trigger one interrupt flag (EXT[n] in
GPIO_IF). The EXTIPSELn[2:0] bits in GPIO_EXTIPSELL or GPIO_EXTIPSELH select which port will
trigger the interrupt flag. The GPIO_EXTIRISE[n] and GPIO_EXTIFALL[n] registers enables sensing of
rising and falling edges. By setting the EXT[n] bit in GPIO_IEN, a high interrupt flag n, will trigger one
of two interrupt lines. The even interrupt line is triggered by any enabled even numbered interrupt flag,
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