LM3S5739 Datasheet, PDF (48/856 Pages) Texas Instruments – Stellaris® LM3S5739 Microcontroller

Architectural Overview
1.4
1.4.1
1.4.1.1
1.4.1.2
1.4.1.3
1.4.1.4
Functional Overview
The following sections provide an overview of the features of the LM3S5739 microcontroller. The
page number in parenthesis indicates where that feature is discussed in detail. Ordering and support
information can be found in “Ordering and Contact Information” on page 850.
ARM Cortex™-M3
Processor Core (see page 55)
All members of the Stellaris product family, including the LM3S5739 microcontroller, are designed
around an ARM Cortex™-M3 processor core. The ARM Cortex-M3 processor provides the core for
a high-performance, low-cost platform that meets the needs of minimal memory implementation,
reduced pin count, and low-power consumption, while delivering outstanding computational
performance and exceptional system response to interrupts.
Memory Map (see page 74)
A memory map lists the location of instructions and data in memory. The memory map for the
LM3S5739 controller can be found in Table 2-4 on page 74. Register addresses are given as a
hexadecimal increment, relative to the module's base address as shown in the memory map.
System Timer (SysTick) (see page 97)
Cortex-M3 includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit
clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter
can be used in several different ways, for example:
■ An RTOS tick timer which fires at a programmable rate (for example, 100 Hz) and invokes a
SysTick routine.
■ A high-speed alarm timer using the system clock.
■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock
used and the dynamic range of the counter.
■ A simple counter. Software can use this to measure time to completion and time used.
■ An internal clock source control based on missing/meeting durations. The COUNTFLAG bit-field
in the control and status register can be used to determine if an action completed within a set
duration, as part of a dynamic clock management control loop.
Nested Vectored Interrupt Controller (NVIC) (see page 98)
The LM3S5739 controller includes the ARM Nested Vectored Interrupt Controller (NVIC) on the
ARM® Cortex™-M3 core. The NVIC and Cortex-M3 prioritize and handle all exceptions. All exceptions
are handled in Handler Mode. The processor state is automatically stored to the stack on an
exception, and automatically restored from the stack at the end of the Interrupt Service Routine
(ISR). The vector is fetched in parallel to the state saving, which enables efficient interrupt entry.
The processor supports tail-chaining, which enables back-to-back interrupts to be performed without
the overhead of state saving and restoration. Software can set eight priority levels on 7 exceptions
(system handlers) and 37 interrupts.
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November 17, 2011
Texas Instruments-Production Data