Architectural Overview
●The Stellaris® family of microcontrollers—the first ARM® Cortex™-M3 based controllers—brings high-performance 32-bit computing to cost-sensitive embedded microcontroller applications. These pioneering parts deliver customers 32-bit performance at a cost equivalent to legacy 8- and 16-bit devices, all in a package with a small footprint.
●Product Features
●The LM3S6911 microcontroller includes the following product features:
●■ 32-Bit RISC Performance
●– 32-bit ARM® Cortex™-M3 v7M architecture optimized for small-footprint embedded applications
●– System timer (SysTick), providing a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism
●– Thumb®-compatible Thumb-2-only instruction set processor core for high code density
●– 50-MHz operation
●– Hardware-division and single-cycle-multiplication
●– Integrated Nested Vectored Interrupt Controller (NVIC) providing deterministic interrupt
●handling
●– 30 interrupts with eight priority levels
●– Memory protection unit (MPU), providing a privileged mode for protected operating system
●functionality
●– Unaligned data access, enabling data to be efficiently packed into memory
●– Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined
●peripheral control
●■ ARM® Cortex™-M3 Processor Core
●– Compact core.
●– Thumb-2 instruction set, delivering the high-performance expected of an ARM core in the memory size usually associated with 8- and 16-bit devices; typically in the range of a few kilobytes of memory for microcontroller class applications.
●– Rapid application execution through Harvard architecture characterized by separate buses for instruction and data.
●– Exceptional interrupt handling, by implementing the register manipulations required for handling an interrupt in hardware.
●– Deterministic, fast interrupt processing: always 12 cycles, or just 6 cycles with tail-chaining
●– Memory protection unit (MPU) to provide a privileged mode of operation for complex applications.
●– Migration from the ARM7™ processor family for better performance and power efficiency.
●– Full-featured debug solution
●• Serial Wire JTAG Debug Port (SWJ-DP)
●• Flash Patch and Breakpoint (FPB) unit for implementing breakpoints
●• Data Watchpoint and Trigger (DWT) unit for implementing watchpoints, trigger resources, and system profiling
●• Instrumentation Trace Macrocell (ITM) for support of printf style debugging
●• Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer
●– Optimized for single-cycle flash usage
●– Three sleep modes with clock gating for low power
●– Single-cycle multiply instruction and hardware divide
●– Atomic operations
●– ARM Thumb2 mixed 16-/32-bit instruction set
●– 1.25 DMIPS/MHz
●■ JTAG
●– IEEE 1149.1-1990 compatible Test Access Port (TAP) controller
●– Four-bit Instruction Register (IR) chain for storing JTAG instructions
●– IEEE standard instructions: BYPASS, IDCODE, SAMPLE/PRELOAD, EXTEST and INTEST
●– ARM additional instructions: APACC, DPACC and ABORT
●– Integrated ARM Serial Wire Debug (SWD)
●■ Hibernation
●– System power control using discrete external regulator
●– Dedicated pin for waking from an external signal
●– Low-battery detection, signaling, and interrupt generation
●– 32-bit real-time clock (RTC)
●– Two 32-bit RTC match registers for timed wake-up and interrupt generation
●– Clock source from a 32.768-kHz external oscillator or a 4.194304-MHz crystal
●– RTC predivider trim for making fine adjustments to the clock rate
●– 64 32-bit words of non-volatile memory
●– Programmable interrupts for RTC match, external wake, and low battery events
●■ Internal Memory
●– 256 KB single-cycle flash
● • User-managed flash block protection on a 2-KB block basis
● • User-managed flash data programming
● • User-defined and managed flash-protection block
●– 64 KB single-cycle SRAM
●■ GPIOs
●– 10-46 GPIOs, depending on configuration
●– 5-V-tolerant in input configuration
●– Fast toggle capable of a change every two clock cycles
●– Programmable control for GPIO interrupts
● • Interrupt generation masking
● • Edge-triggered on rising, falling, or both
● • Level-sensitive on High or Low values
●– 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
● • 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
