LM3S6950 Datasheet, PDF (32/524 Pages) List of Unclassifed Manufacturers – Microcontroller

Architectural Overview
1.4.4
1.4.4.1
1.4.4.2
1.4.4.3
1.4.5
1.4.5.1
1.4.5.2
System Peripherals
Programmable GPIOs (see page 157)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections.
The Stellaris^® GPIO module is composed of seven physical GPIO blocks, each corresponding to
an individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation
IP for Real-Time Microcontrollers specification) and supports 1-46 programmable input/output pins.
The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page
469 for the signals available to each GPIO pin).
The GPIO module features programmable interrupt generation as either edge-triggered or
level-sensitive on all pins, programmable control for GPIO pad configuration, and bit masking in
both read and write operations through address lines.
Four Programmable Timers (see page 197)
Programmable timers can be used to count or time external events that drive the Timer input pins.
The Stellaris^® General-Purpose Timer Module (GPTM) contains four GPTM blocks. Each GPTM
block provides two 16-bit timer/counters that can be configured to operate independently as timers
or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC).
When configured in 32-bit mode, a timer can run as a one-shot timer, periodic timer, or Real-Time
Clock (RTC). When in 16-bit mode, a timer can run as a one-shot timer or periodic timer, and can
extend its precision by using an 8-bit prescaler. A 16-bit timer can also be configured for event
capture or Pulse Width Modulation (PWM) generation.
Watchdog Timer (see page 230)
A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is
reached. The watchdog timer is used to regain control when a system has failed due to a software
error or to the failure of an external device to respond in the expected way.
The Stellaris^® Watchdog Timer module consists of a 32-bit down counter, a programmable load
register, interrupt generation logic, and a locking register.
The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out,
and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured,
the lock register can be written to prevent the timer configuration from being inadvertently altered.
Memory Peripherals
The LM3S6950 controller offers both SRAM and Flash memory.
SRAM (see page 133)
The LM3S6950 static random access memory (SRAM) controller supports 64 KB SRAM. The internal
SRAM of the Stellaris^® devices is located at offset 0x0000.0000 of the device memory map. To
reduce the number of time-consuming read-modify-write (RMW) operations, ARM has introduced
bit-banding technology in the new Cortex-M3 processor. With a bit-band-enabled processor, certain
regions in the memory map (SRAM and peripheral space) can use address aliases to access
individual bits in a single, atomic operation.
Flash (see page 134)
The LM3S6950 Flash controller supports 256 KB of flash memory. The flash is organized as a set
of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the
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June 14, 2007
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