02 June 2009
Atmel First ARM Cortex-M3 Flash MCU With On Chip USB Atmel, a member of the ARM Connected Community, has taken the wraps off the SAM3U, the industry's first ARM Cortex-M3 Flash microcontroller integrating high speed (480 Mbps) USB Device-and-Transceiver, 4-bit 192 Mbps SDIO/SDCard 2.0, 8-bit 384 Mbps MMC 4.3 Host and 48 Mpbs SPI interfaces on-chip. This connectivity, together with the SAM3U's 96 MHz/1.25 DMIPS/MHz operating frequency, makes the SAM3U suitable for applications with intensive communications requirements, such high speed gateways in industrial, medical, data processing and consumer applications. The introduction of the SAM3U expands Atmel's 32-Bit MCU portfolio consisting of ARM and AVR32 products. Jacko Wilbrink, Atmel's Marketing Director for ARM-based Microcontrollers, commented, "Atmel was the first to adapt USB Full Speed in its ARM Flash MCUs as a de-facto standard peripheral and we are now driving the deployment of USB High Speed in the embedded space. USB Full Speed at 12 Mbps displaced the UART; USB High Speed at 480 Mbps has the potential to replace parallel wire interconnections, reducing cost, improving reliability and improving EMI characteristics".To fully exploit the SAM3U's high speed communications peripherals, the device is built around a high data-bandwidth architecture with a 5-layer bus matrix, 23 DMA channels and distributed on-chip memory including up to 52k Bytes of SRAM split in three blocks and up to 256k Bytes of Flash in two banks. The dual bank Flash offers in-application programming (IAP) where one memory bank is written with a new version of the firmware while the processor executes from the other bank. A programmable boot feature enables switching between the two Flash banks at the next MCU reboot. Additional features include an 8-channel each 10- and 12-bit ADC, the latter with integrated Programmable Gain Amplifier (PGA), differential and single ended input to remove external OpAmps and a one Msps sample rate, 4 UARTs, 5 SPI, 2 I2C, I2S, timers, PWM, 128-bit unique ID, and power and reset management. The External Bus Interface offers the choice between 8- and 16-bit data bus widths for extended memory or connection to external FPGAs and ASSPs. The SAM3U's supply voltage ranges from 1.62V to 3.6V, a feature not commonly found on Cortex-M3-based MCUs. The Cortex-M3 core has a completely new instruction set architecture, different from previous ARM cores, according to Atmel. Migrating legacy ARM7 code to the Cortex-M3 requires a complete re-write of the assembler code. Atmel has taken steps to ensure maximum code portability between its ARM7-, ARM9- and Cortex-M3-based microcontrollers. Its SAM7, SAM9 and Cortex-M3-based SAM3 MCUs 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. The AT91SAM3U is available in Flash memory densities of 64k, 128k and 256k Bytes. | 
