AT91SAM (AT91SAM Smart ARM-based Microcontrollers) are a family of Atmel chips based on the 32-bit RISC microprocessors from ARM[1]. Some are targeted as applications processors, with external memory busses used to access RAM (SDRAM or DDR2) and flash, and large sets of integrated peripherals. When targeted as microcontrollers they include embedded Flash and SRAM memories together with a number of peripherals and standard communications and networking interfaces. This qualifies them as system-on-a-chip devices.
The AT91SAM comes in ARM7, ARM9 and Cortex M3 versions.
External interfaces include USB, CAN, Ethernet, SPI, USART and ADC. A DMA controller provides direct communication channels between external interfaces and memories, increasing data throughput with minimal processor intervention.
Peripherals include counter/timers, power-on reset generators, voltage regulators and advanced interrupt controller. This enhances the real-time performance of the processor. A power management controller keeps power consumption to a minimum by powering down unused peripherals and interfaces, and enabling the processor to be put in standby mode.