Atmel Highly-Integrated Cortex-M3-based Flash MCUs Improve Impedance Matching and Lower Power Up to 50 Percent

The SAM3S is a member of Atmel's Flash microcontroller family based on the high-performance 32-bit ARM Cortex-M3 RISC processor. It provides processing power and features such as system control, sensor interfaces, 64k to 256kByte Flash memory options, an optional external parallel bus interface, connectivity capabilities and user interface support. Additional features include On-Die Termination (ODT), USB Device, SDIO, Parallel PIO signal capture, 12-bit ADC and DAC, 4 UARTs, dual I2C, I2S, timers, unique chip ID, and power and reset management. The SAM3S's supply voltage ranges from 1.62 to 3.6V operation and package options from 48-pin QFP and QFN up to 100-pin QFP and BGA.



On-Die Termination (ODT) simplifies PCB Design - Termination resistors are conventionally added externally to improve impedance matching in transmission lines and avoid signal reflection which can result in erroneous data transmission and current peaks degrading the EMI behavior of the system. ODT consists of integrating the termination resistor inside a semiconductor chip instead of on a printed circuit board. The SAM3S has integrated series resistors on the outputs with a typical value of 35 Ohms, which result in a reduced BOM cost, real estate savings and facilitate PCB design.



Power optimization at reduced operating frequency - Atmel has taken the following steps to minimize the dynamic power consumption of the SAM3U devices in operating modes up to 10 MHz reaching an estimated power consumption reduction at 1 MHz of 50 percent:

1) Extended supply range from 1.62V to 3.6V

2) Sense amplifiers of the Flash memory are automatically put to sleep after completion of the read cycle

3) The Flash memory can be read in x64 mode instead of x128 without compromising performance

4) A self-adapting regulator scales current consumption as a function of current draw without any software handling



Parallel IO Capture Mode - The SAM3S is the first ARM MCU with parallel data capture mode on PIOs and DMA support. The parallel data capture mode on the PIOs complements the external bus interface for data collection from external devices not compliant with standard memory read protocols, such as low-cost image sensors. Read control signals and the clock are user programmable and data is transferred to memory by DMA offloading the CPU. The security market is moving towards the integration of camera functionality in PIR sensors. The parallel PIO capture mode can interface to image sensors, making the SAM3S a perfect low-cost MCU for next-generation PIR cameras.



Improved safety and security - The SAM3S significantly improves the safety and security features. The Memory Protection Unit (MPU) ensures code protection and secures multi-application/task execution. The hardware CRC with DMA checks the memory integrity in the background, and triggers an interrupt in case of corruption. The ECC detects and corrects single-bit failures on the embedded Flash memory. A 128-bit unique ID and the scrambled external bus interface ensure external software confidentiality while the security bit ensures internal software confidentiality. A mechanism detects clock failure and automatic switches on internal RC oscillator while configuring the outputs of the PWM in a defined state.



Pin-to-pin compatibility between SAM3S and SAM7S MCUs - The SAM3S series is the ideal Cortex-M3 upgrade path for the SAM7S and SAM7SE, Atmel's best-selling ARM® Flash MCU. With the Cortex-M3 core running at a maximum clock rate of 64 MHz at 1.8V, 85°C, the SAM3S Flash MCU brings a 50 percent raw performance increase over the SAM7S series. In its 64-pin version, the SAM3S is pin-to-pin compatible with the SAM7S, enabling customers to upgrade performance while hardware remains unchanged to preserve investments previously made.



Near-recompile-and-go code portability - The Cortex-M3 core has a completely new instruction set architecture, different from previous ARM7 and ARM9 cores. The 32-bit ARM instruction set has been replaced by a variable length Thumb-2, offering similar performance and 26 percent better code density. Migrating legacy ARM assembly code to the CM3 requires a complete re-write. Atmel has taken steps to ensure maximum code portability between its ARM7-, ARM9- and Cortex-M3-based microcontrollers. Atmel's SAM7, SAM9 and Cortex-M3-based SAM3 devices have identical hardware abstraction layers and a unified programming model, as well as common peripherals that provide near-recompile-and-go code portability between devices. For more details about code portability from ARM7TDMI to Cortex-M3, refer to the article published by Todd Hixon on October 30, 2009 at http://www.embedded.com/design/220900313 entitled Migrating ARM7 code to a Cortex-M3 MCU.



Renewed peripheral set - The SAM3S integrates up to 16 channels on the one mega samples per second (Msps) 12-bit Analog to Digital Converter (ADC) with support for both single-ended and differential inputs. A programmable gain amplifier increases the range of small signals that can benefit from the full-scale 12-bit ADC resolution. Small signals can be amplified up to 4 times. The SAM3S also features a 2-channel 12-bit Digital to Analog Converter (DAC), one analog comparator and a temperature sensor. Connectivity to standard multimedia cards is possible due to the integration of a high-speed SDIO/SD/MMC interface. The USB device with its integrated transceiver have been upgraded with 8 endpoints, a 2688 bytes FIFO, a dedicated PLL, integrated resistors, and is available in 48-pin package for space constraint applications. The SAM3S is hardware-ready for motor control with its advanced PWM, quadrature decoder on 16-bit general-purpose timers, gray counter and hardware synchronization between Timers and ADC.



High data speedway architecture - The combination of a 4-layer AHB system bus matrix natively supported by the Cortex-M3 processor, distributed memory and 21-peripheral DMA channels ensures uninterrupted data flows in parallel with minimum processor overhead. The DMA is tightly integrated in the peripheral programmer's interface, greatly simplifying driver development and reducing processor overhead in data transfers.

Comprehensive support eco-system and In-System-Programming - Atmel's SAM3S flash MCU is supported by a rapidly-growing number of development tools, real-time operating systems (RTOS), middleware products and technical support services from industry-leading third parties that include IAR(TM), Keil(TM), Micrium® and Segger. The automatic reboot from the on-chip ROM after Flash memory erase facilitates In-System production programming. Atmel provides a software package with register descriptions and device drivers for all peripherals, along with project examples that create an easier use of the microcontroller.



Availability and Pricing - The SAM3S is available in Flash memory densities of 64k, 128k and 256k Bytes and ships in 48-, 64- and 100-pin QFP, 48- and 64-pin QFN packages, and in 100-pin 0.8 mm pitch BGA packages. Sampling starts with the 256kByte Flash memory density parts in 64- and 100-pin QFP packages and the others will f