LM3S3739 Luminary Micro, Inc, LM3S3739 Datasheet - Page 36

• Manufacturer Part Number: LM3S3739
• Description: Lm3s3739 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

Architectural Overview
1.4.5.3
1.4.6
1.4.6.1
1.4.6.2
1.4.6.3
1.4.7
1.4.7.1
36
Watchdog Timer (see page 322)
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
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 LM3S3739 controller offers both single-cycle SRAM and single-cycle Flash memory.
SRAM (see page 151)
The LM3S3739 static random access memory (SRAM) controller supports 64 KB SRAM. The internal
SRAM of the Stellaris
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 152)
The LM3S3739 Flash controller supports 128 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
block to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually
protected. The blocks can be marked as read-only or execute-only, providing different levels of code
protection. Read-only blocks cannot be erased or programmed, protecting the contents of those
blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only
be read by the controller instruction fetch mechanism, protecting the contents of those blocks from
being read by either the controller or by a debugger.
ROM
The LM3S3739 microcontroller ships with the Stellaris
preprogrammed in read-only memory (ROM). The Stellaris
software library for controlling on-chip peripherals, and includes a boot-loader capability. The library
performs both peripheral initialization and peripheral control functions, with a choice of polled or
interrupt-driven peripheral support, and takes full advantage of the stellar interrupt performance of
the ARM® Cortex™-M3 core. No special pragmas or custom assembly code prologue/epilogue
functions are required. For applications that require in-field programmability, the royalty-free Stellaris
boot loader included in the Stellaris
support in-field firmware updates.
Additional Features
Memory Map (see page 44)
A memory map lists the location of instructions and data in memory. The memory map for the
LM3S3739 controller can be found in “Memory Map” on page 44. Register addresses are given as
a hexadecimal increment, relative to the module's base address as shown in the memory map.
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Watchdog Timer module consists of a 32-bit down counter, a programmable load
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devices is located at offset 0x0000.0000 of the device memory map. To
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Peripheral Driver Library can act as an application loader and
Preliminary
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family Peripheral Driver Library conveniently
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Peripheral Driver Library is a royalty-free
June 02, 2008
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