LM3S308 Luminary Micro, Inc, LM3S308 Datasheet - Page 126

• Manufacturer Part Number: LM3S308
• Description: Lm3s308 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 five physical GPIO blocks, each corresponding to an individual
GPIO port (Port A, Port B, Port C, Port D, and Port E, ). The GPIO module supports 5-28
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 127). The LM3S308 microcontroller contains five ports and thus five 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
Slew rate control for the 8-mA drive
Open drain enables
Digital input enables
All GPIO pins are inputs by default (GPIODIR=0 and GPIOAFSEL=0), with the exception
of the five JTAG pins (PB7 and PC[3:0]). The JTAG pins default to their JTAG
functionality (GPIOAFSEL=1). A Power-On-Reset (POR) or asserting an external reset
(RST) puts both groups of pins back to their default state.
Preliminary
June 04, 2008