LM3S2739 Datasheet, PDF (155/532 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S2739 Microcontroller
9 General-Purpose Input/Outputs (GPIOs)
9.1
9.1.1
9.1.1.1
The GPIO module is composed of eight physical GPIO blocks, each corresponding to an individual
GPIO port (Port A, Port B, Port C, Port D, Port E, Port F, Port G, and Port H). The GPIO module is
FiRM-compliant and supports 18-56 programmable input/output pins, depending on the peripherals
being used.
The GPIO module has the following features:
■ Programmable control for GPIO interrupts
– Interrupt generation masking
– Edge-triggered on rising, falling, or both
– Level-sensitive on High or Low values
■ 5-V-tolerant input/outputs
■ Bit masking in both read and write operations through address lines
■ Programmable control for GPIO pad configuration
– Weak pull-up or pull-down resistors
– 2-mA, 4-mA, and 8-mA pad drive
– Slew rate control for the 8-mA drive
– Open drain enables
– Digital input enables
Function Description
Important: All GPIO pins are tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0,
and GPIOPUR=0), with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]).
The JTAG/SWD pins default to their JTAG/SWD functionality (GPIOAFSEL=1,
GPIODEN=1 and GPIOPUR=1). A Power-On-Reset (POR) or asserting RST puts both
groups of pins back to their default state.
Each GPIO port is a separate hardware instantiation of the same physical block. The LM3S2739
microcontroller contains eight ports and thus eight of these physical GPIO blocks.
Data Control
The data control registers allow software to configure the operational modes of the GPIOs. The data
direction register configures the GPIO as an input or an output while the data register either captures
incoming data or drives it out to the pads.
Data Direction Operation
The GPIO Direction (GPIODIR) register (see page 163) is used to configure each individual pin as
an input or output. When the data direction bit is set to 0, the GPIO is configured as an input and
the corresponding data register bit will capture and store the value on the GPIO port. When the data
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Preliminary