[LUMINARY MICRO]

Architectural Overview

The Luminary Micro 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 LM3S817 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) provides 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

– 26 interrupts with eight priority levels

– Memory protection unit (MPU) provides a privileged mode for protected operating system functionality

– Unaligned data access, enabling data to be efficiently packed into memory

– Atomic bit manipulation (bit-banding) delivers maximum memory utilization and streamlined peripheral control

■ Internal Memory

– 64-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

– 8-KB single-cycle SRAM

■ General-Purpose Timers

– Three timers, each of which can be configured: as a single 32-bit timer, as two 16-bit timers, or to initiate an ADC event

– 32-bit Timer modes:

? Programmable one-shot timer

? Programmable periodic timer

? Real-Time Clock when using an external 32.768-KHz clock as the input

? User-enabled stalling in periodic and one-shot mode when the controller asserts the CPU Halt flag during debug

? ADC event trigger

– 16-bit Timer modes:

? General-purpose timer function with an 8-bit prescaler

? Programmable one-shot timer

? Programmable periodic timer

? User-enabled stalling when the controller asserts CPU Halt flag during debug

? ADC event trigger

– 16-bit Input Capture modes:

? Input edge count capture

? Input edge time capture

– 16-bit PWM mode:

? Simple PWM mode with software-programmable output inversion of the PWM signal

■ ARM FiRM-compliant Watchdog Timer

– 32-bit down counter with a programmable load register

– Separate watchdog clock with an enable

– Programmable interrupt generation logic with interrupt masking

– Lock register protection from runaway software

– Reset generation logic with an enable/disable

– User-enabled stalling when the controller asserts the CPU Halt flag during debug

■ Synchronous Serial Interface (SSI)

– Master or slave operation

– Programmable clock bit rate and prescale

– Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep

– Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces

– Programmable data frame size from 4 to 16 bits

– Internal loopback test mode for diagnostic/debug testing

■ UART

– Two fully programmable 16C550-type UARTs

– Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs to reduce CPU interrupt service loading

– Programmable baud-rate generator with fractional divider

– Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface

– FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8

– Standard asynchronous communication bits for start, stop, and parity

– False-start-bit detection

– Line-break generation and detection

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