LM3S2139 Luminary Micro, Inc, LM3S2139 Datasheet - Page 140

• Manufacturer Part Number: LM3S2139
• Description: Lm3s2139 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

General-Purpose Input/Outputs (GPIOs)
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8.1
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General-Purpose Input/Outputs (GPIOs)
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
supports 26-56 programmable input/output pins, depending on the peripherals being used.
The GPIO module has the following features:
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Functional Description
Important:
Each GPIO port is a separate hardware instantiation of the same physical block (see Figure
8-1 on page 141). The LM3S2139 microcontroller contains eight ports and thus eight of these physical
GPIO blocks.
Programmable control for GPIO interrupts
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5-V-tolerant input/outputs
Bit masking in both read and write operations through address lines
Pins configured as digital inputs are Schmitt-triggered.
Programmable control for GPIO pad configuration:
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Interrupt generation masking
Edge-triggered on rising, falling, or both
Level-sensitive on High or Low values
Weak pull-up or pull-down resistors
2-mA, 4-mA, and 8-mA pad drive for digital communication; up to four pads can be configured
with an 18-mA pad drive for high-current applications
Slew rate control for the 8-mA drive
Open drain enables
Digital input enables
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.
Preliminary
July 25, 2008